Increased soluble Fas ligand levels in patients with Stevens-Johnson syndrome and toxic epidermal necrolysis preceding skin detachment

Acute and chronic ocular outcomes in SJS/TEN patients treated with oral ciclosporin vs intravenous immunoglobulin

Background/Aim

To evaluate differences in ocular complications of Stevens Johnson Syndrome (SJS)/Toxic Epidermal Necrolysis (TEN) patients receiving either systemic IVIG or Ciclosporin (CsA) as initial treatments.

Methods

Retrospective review of consecutive patients admitted for SJS/TEN at the Singapore General Hospital (SGH) from 2011 to 2017 who received either IVIG or Ciclosporin at the onset of the disease and had ophthalmological follow-up of at least 6 months were included. Acute ocular severity of SJS/TEN was graded using the Gregory grading score; chronic ocular complications were graded using the Sotozono system.

Results

A total of 18 subjects were included for analysis, with eight in the IVIG group and 10 in the CsA group. There were no significant differences in acute Gregory severity grading between the two groups. The CsA group had a trend towards worse overall chronic Sotozono grading scores compared to the IVIG group (median [IQR]: 2 [0-3] vs. 1 [0-6.5], p = 0.27), with a higher incidence of acute severe cornea involvement (60% vs. 25%, p = 0.93) and chronic corneal and eyelid involvement in the former than the latter. SJS/TEN patients with worse acute ocular involvement were more likely to have TEN and perianal mucosal involvement (50% vs. 0, p = 0.01).

Conclusion

Compared to those who received IVIG, SJS/TEN patients who received CsA at the acute disease stage, seemed to have worse acute corneal and chronic corneal and eyelid complications. Larger studies are needed to confirm this finding.

Greater mechanistic understanding of the cutaneous pathogenesis of Stevens-Johnson syndrome/toxic epidermal necrolysis can shed light on novel therapeutic strategies: a comprehensive review

PURPOSE OF REVIEW

Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) are severe cutaneous adverse drug reactions (SCARs) characterized by widespread epithelial detachment and blistering, which affects the skin and mucocutaneous membranes. To date, therapeutic interventions for SJS/TEN have focused on systematic suppression of the inflammatory response using high-dose corticosteroids or intravenous immunoglobulin G (IgG), for example. No targeted therapies for SJS/TEN currently exist.

RECENT FINDINGS

Though our understanding of the pathogenesis of SJS/TEN has advanced from both an immunological and dermatological perspective, this knowledge is yet to translate into the development of new targeted therapies.

SUMMARY

Greater mechanistic insight into SJS/TEN would potentially unlock new opportunities for identifying or repurposing targeted therapies to limit or even prevent epidermal injury and blistering.

A systematic review of case-control studies of cytokines in blister fluid and skin tissue of patients with Stevens Johnson syndrome and toxic epidermal necrolysis

Stevens Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are severe cutaneous adverse reactions characterised by keratinocyte apoptosis, necroptosis and epidermal detachment. Several cytokines and cytotoxic proteins have been shown to be elevated in the blood and skin of SJS/TEN sufferers and biologics such as intravenous immune globulin and tumour necrosis factor (TNF)-alpha inhibitors have demonstrated good therapeutic potential. The exact pathogenic model of SJS/TEN however remains elusive. This systematic review aimed to evaluate the case-control studies of cytokines and cytotoxic proteins in the blister fluid and skin of adults with Stevens Johnson syndrome and/or toxic epidermal necrolysis. This review was registered with INPLASY and conducted in accordance with the PRISMA reporting guidelines. Potential bias was assessed using the NIH criteria. Eleven articles describing results from 96 cases and 170 controls were included. Fas, Fas ligand, Interleukin (IL)-8 and B-cell lymphoma (Bcl)-2 were elevated in SJS/TEN blister fluid and skin tissue, compared with healthy controls. IL-2, IL-6, TNF-alpha, tumour necrosis factor-related apoptosis-inducing ligand (TRAIL), interferon-gamma and matrix metalloproteinase-2 were elevated in SJS/TEN blister fluid compared with fluid sampled from lesional controls. Granulysin, IL-33, TGF-beta-1 and IL-13 were elevated in SJS/TEN skin tissue compared with lesional lichen planus tissue, as was IL-13, IFN-gamma, IL-2 and IL-5, when compared with erythema multiforme tissue. A wide array of cytokines and cytotoxic proteins are present at higher concentrations in the blister fluid and skin tissue of SJS/TEN patients compared with healthy and lesional controls. Our findings suggest that these proteins may be pathogenic, as well as possibly markers for diagnosis, disease severity and course. They may also prove to be useful therapeutic targets. More research is needed.

Correlations between histopathologic findings, serum biomarker levels, and clinical outcomes in Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN)

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are severe dermatological emergencies. The role of cytokines and chemokines in the pathogenesis, progression of the disease, and histopathologic features is not fully elucidated. To address this gap, we conducted a retrospective study examining the associations between 42 serum biomarkers, histopathologic findings, and clinical outcomes in SJS/TEN patients. We reviewed the medical records of 23 patients diagnosed with SJS/TEN. Regarding histopathology, our study did not reveal any significant associations between the degree of epidermal necrosis, dermal mononuclear cell infiltration, and clinical outcomes. However, an intriguing observation was made regarding the degree of dermal infiltration of CD8 + cells, which showed a negative correlation with the severity of acute ocular complications. Notably, serum levels of IFN-γ positively correlated with the number of CD8 + cells in dermal infiltration. Additionally, higher serum levels of myeloperoxidase were associated with greater degrees of epidermal necrosis, while serum Fas ligand and stem cell factor levels were elevated in individuals with increased dermal mononuclear cell infiltration. Furthermore, the levels of S100A8/A9 were significantly correlated with the SCORTEN and mortality rate. These findings provide insights into the intricate pathogenesis of the disease.

Evaluation of Plasmapheresis vs Immunoglobulin as First Treatment After Ineffective Systemic Corticosteroid Therapy for Patients With Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis

Importance

Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS/TEN) are severe cutaneous adverse reactions, and patients with SJS/TEN frequently require intensive care. However, there is limited evidence on the clinical outcomes of immunomodulating therapy, including plasmapheresis and intravenous immunoglobulin (IVIG) in patients with SJS/TEN.

Objective

To compare clinical outcomes of patients with SJS/TEN who were treated with plasmapheresis first vs IVIG first after ineffective systemic corticosteroid therapy.

Design, Setting, and Participants

This retrospective cohort study used data from a national administrative claims database in Japan that included more than 1200 hospitals and was conducted from July 2010 to March 2019. Inpatients with SJS/TEN who received plasmapheresis and/or IVIG therapy after initiation of at least 1000 mg/d of methylprednisolone equivalent systemic corticosteroid therapy within 3 days of hospitalization were included. Data were analyzed from October 2020 to May 2021.

Exposures

Patients who received IVIG or plasmapheresis therapy within 5 days after initiation of systemic corticosteroid therapy were included in the IVIG- and plasmapheresis-first groups, respectively.

Main Outcomes and Measures

In-hospital mortality, length of hospital stay, and medical costs.

Results

Of 1215 patients with SJS/TEN who had received at least 1000 mg/d of methylprednisolone equivalent within 3 days of hospitalization, 53 and 213 patients (mean [SD] age, 56.7 [20.2] years; 152 [57.1%] women) were included in the plasmapheresis- and IVIG-first groups, respectively. Propensity-score overlap weighting showed no significant difference in inpatient mortality rates between the plasmapheresis- and IVIG-first groups (18.3% vs 19.5%; odds ratio, 0.93; 95% CI, 0.38-2.23; P = .86). Compared with the IVIG-first group, the plasmapheresis-first group had a longer hospital stay (45.3 vs 32.8 days; difference, 12.5 days; 95% CI, 0.4-24.5 d; P = .04) and higher medical costs (US $34 262 vs $23 054; difference, US $11 207; 95% CI, $2789-$19 626; P = .009).

Conclusions and Relevance

This nationwide retrospective cohort study found no significant benefit to administering plasmapheresis therapy first instead of IVIG first after ineffective systemic corticosteroid treatment in patients with SJS/TEN. However, medical costs and length of hospital stay were greater for the plasmapheresis-first group.

Inhibition of tumor necrosis factor improves conventional steroid therapy for Stevens-Johnson syndrome/toxic epidermal necrolysis in a cohort of patients

BACKGROUND

Systemic steroid therapies for Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN) have been challenged because of their limited benefits. Whether additional tumor necrosis factor (TNF) α inhibition provides an optimized approach remains unexplored.

OBJECTIVE

To investigate the efficacy of TNF-α inhibition combined with a steroid to treat SJS/TEN and to identify potential biomarkers.

METHODS

Twenty-five patients with SJS/TEN were recruited and divided into 2 groups: 10 patients received methylprednisolone and 15 patients received etanercept plus methylprednisolone. Serum levels of granzyme B, perforin, interferon-γ, interleukin (IL) 6, IL-15, IL-18, macrophage inflammatory protein 1α, macrophage inflammatory protein 1β, and TNF-α were measured by multiplex cytokine analysis kits during the acute and resolution phases.

RESULTS

Compared with the steroid monotherapy, the combination therapy significantly shortened the course of the initial steroid treatment and the duration of the acute stage, hospitalization stay, and skin re-epithelialization. Although both therapies significantly reduced IL-15 levels; the combination therapy also decreased IL-6 and IL-18 levels. While the level of IL-15 was positively correlated with skin re-epithelialization time in both groups, the level of IL-6 served as an additional marker for the course of the disease in the combination therapy group.

LIMITATIONS

The cohort size is relatively small.

CONCLUSION

Additional TNF-α inhibition to steroid treatment appeared to improve outcomes for SJS/TEN.

Deep Neural Network for Early Image Diagnosis of Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis

BACKGROUND

Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN) is a life-threatening cutaneous adverse drug reaction (cADR). Distinguishing SJS/TEN from nonsevere cADRs is difficult, especially in the early stages of the disease.

OBJECTIVE

To overcome this limitation, we developed a computer-aided diagnosis system for the early diagnosis of SJS/TEN, powered by a deep convolutional neural network (DCNN).

METHODS

We trained a DCNN using a dataset of 26,661 individual lesion images obtained from 123 patients with a diagnosis of SJS/TEN or nonsevere cADRs. The DCNN's accuracy of classification was compared with that of 10 board-certified dermatologists and 24 trainee dermatologists.

RESULTS

The DCNN achieved 84.6% sensitivity (95% confidence interval [CI], 80.6-88.6), whereas the sensitivities of the board-certified dermatologists and trainee dermatologists were 31.3 % (95% CI, 20.9-41.8; P < .0001) and 27.8% (95% CI, 22.6-32.5; P < .0001), respectively. The negative predictive value was 94.6% (95% CI, 93.2-96.0) for the DCNN, 68.1% (95% CI, 66.1-70.0; P < .0001) for the board-certified dermatologists, and 67.4% (95% CI, 66.1-68.7; P < .0001) for the trainee dermatologists. The area under the receiver operating characteristic curve of the DCNN for a SJS/TEN diagnosis was 0.873, which was significantly higher than that for all board-certified dermatologists and trainee dermatologists.

CONCLUSIONS

We developed a DCNN to classify SJS/TEN and nonsevere cADRs based on individual lesion images of erythema. The DCNN performed significantly better than did dermatologists in classifying SJS/TEN from skin images.

Diagnostic Tools and Biomarkers for Severe Drug Eruptions

In accordance with the development of human technology, various medications have been speedily developed in the current decade. While they have beneficial impact on various diseases, these medications accidentally cause adverse reactions, especially drug eruption. This delayed hypersensitivity reaction in the skin sometimes causes a life-threatening adverse reaction, namely Stevens-Johnson syndrome and toxic epidermal necrolysis. Therefore, how to identify these clinical courses in early time points is a critical issue. To improve this problem, various biomarkers have been found for these severe cutaneous adverse reactions through recent research. Granulysin, Fas ligands, perforin, and granzyme B are recognized as useful biomarkers to evaluate the early onset of Stevens-Johnson syndrome and toxic epidermal necrolysis, and other biomarkers, such as miRNAs, high mobility group box 1 protein (HMGB1), and S100A2, which are also helpful to identify the severe cutaneous adverse reactions. Because these tools have been currently well developed, updates of the knowledge in this field are necessary for clinicians. In this review, we focused on the detailed biomarkers and diagnostic tools for drug eruption and we also discussed the actual usefulness of these biomarkers in the clinical aspects based on the pathogenesis of drug eruption.

The Emerging Role of the Innate Immune Response in Idiosyncratic Drug Reactions

Idiosyncratic drug reactions (IDRs) range from relatively common, mild reactions to rarer, potentially life-threatening adverse effects that pose significant risks to both human health and successful drug discovery. Most frequently, IDRs target the liver, skin, and blood or bone marrow. Clinical data indicate that most IDRs are mediated by an adaptive immune response against drug-modified proteins, formed when chemically reactive species of a drug bind to self-proteins, making them appear foreign to the immune system. Although much emphasis has been placed on characterizing the clinical presentation of IDRs and noting implicated drugs, limited research has focused on the mechanisms preceding the manifestations of these severe responses. Therefore, we propose that to address the knowledge gap between drug administration and onset of a severe IDR, more research is required to understand IDR-initiating mechanisms; namely, the role of the innate immune response. In this review, we outline the immune processes involved from neoantigen formation to the result of the formation of the immunologic synapse and suggest that this framework be applied to IDR research. Using four drugs associated with severe IDRs as examples (amoxicillin, amodiaquine, clozapine, and nevirapine), we also summarize clinical and animal model data that are supportive of an early innate immune response. Finally, we discuss how understanding the early steps in innate immune activation in the development of an adaptive IDR will be fundamental in risk assessment during drug development. SIGNIFICANCE STATEMENT: Although there is some understanding that certain adaptive immune mechanisms are involved in the development of idiosyncratic drug reactions, the early phase of these immune responses remains largely uncharacterized. The presented framework refocuses the investigation of IDR pathogenesis from severe clinical manifestations to the initiating innate immune mechanisms that, in contrast, may be quite mild or clinically silent. A comprehensive understanding of these early influences on IDR onset is crucial for accurate risk prediction, IDR prevention, and therapeutic intervention.

Current Pharmacogenetic Perspective on Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis

Adverse drug reactions are a public health issue that draws widespread attention, especially for Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) which have high mortality and lack of efficacious treatment. Though T-cell-mediated HLA-interacted immune response has been extensively studied, our understanding of the mechanism is far from satisfactory. This review summarizes infection (virus, bacterial, and mycoplasma infection), an environmental risk factor, as a trigger for SJS/TEN. The mutations or polymorphisms of drug metabolic enzymes, transporters, receptors, the immune system genes, and T-cell-mediated apoptosis signaling pathways that contribute to SJS/TEN are discussed and summarized. Epigenetics, metabolites, and mobilization of regulatory T cells and tolerogenic myeloid precursors are emerged directions to study SJS/TEN. Ex vivo lymphocyte transformation test has been exploited to aid in identifying the causative drugs. Critical questions on the pathogenesis of SJS/TEN underlying gene polymorphisms and T cell cytotoxicity remain: why some of the patients carrying the risky genes tolerate the drug and do not develop SJS/TEN? What makes the skin and mucous membrane so special to be targeted? Do they relate to skin/mucous expression of transporters? What is the common machinery underlying different HLA-B alleles associated with SJS/TEN and common metabolites?

An Updated Review of the Diagnostic Methods in Delayed Drug Hypersensitivity

Delayed drug hypersensitivity reactions are clinically diverse reactions that vary from isolated benign skin conditions that remit quickly with no or symptomatic treatment, drug discontinuation or even continued drug treatment, to the other extreme of severe cutaneous adverse reactions (SCARs) that are associated with presumed life-long memory T-cell responses, significant acute and long-term morbidity and mortality. Diagnostic "in clinic" approaches to delayed hypersensitivity reactions have included patch testing (PT), delayed intradermal testing (IDT) and drug challenges for milder reactions. Patch and IDT are, in general, performed no sooner than 4-6 weeks after resolution of the acute reaction at the maximum non-irritating concentrations. Functional in vitro and ex vivo assays have largely remained the province of research laboratories and include lymphocyte transformation test (LTT) and cytokine release enzyme linked ImmunoSpot (ELISpot) assay, an emerging diagnostic tool which uses cytokine release, typically IFN-γ, after the patient's peripheral blood mononuclear cells are stimulated with the suspected drug(s). Genetic markers such as human leukocyte antigen have shown recent promise for both pre-prescription screening as well as pre-emptive and diagnostic testing strategies.

Serum levels of soluble Fas and Fas ligand in pregnant women who smoke

PROBLEM

Cigarette smoking during pregnancy is associated with reduced incidence of preeclampsia. Mechanisms of this association are poorly understood. Cytokines, angiogenic, and anti-angiogenic factors are involved in the pathogenesis of preeclampsia. During normal pregnancy, Fas ligand (FasL) present on trophoblasts induces apoptosis of Fas bearing maternal immune cells. In preeclampsia, trophoblasts show increased apoptosis with reduced expression of FasL. We determined serum levels of cytokines, angiogenic (placental growth factor), anti-angiogenic factors (soluble endoglin, soluble fms-like tyrosine kinase-1), soluble Fas (sFas), and soluble FasL (sFasL) in smoking and non-smoking pregnant women.

METHODS

Using enzyme-linked immunosorbent and multiplex assays, we prospectively analyzed serum levels of angiogenic, anti-angiogenic factors, cytokines, sFas and sFasL in normotensive smoking and non-smoking mothers. Exclusion criteria included maternal hypertension, auto-immune disorders, rupture of membranes, evidence of labor, and drug use.

RESULTS

Of 100 women recruited to the study, 51 were in the non-smoking and 49 in the smoking group. Except for lower maternal age in the smoking group, there was no difference in gestation, BMI, gravidity, or ethnicity between the two groups. Levels of angiogenic, anti-angiogenic factors, cytokines, and sFas were similar between the two groups but sFasL levels were significantly higher in smoking group (38 pg/ml vs. 16 pg/ml, p < .001) and remained significant after controlling for confounders.

CONCLUSION

Our study demonstrates higher sFasL levels in pregnant women who smoke. Higher sFasL may explain the reduced incidence of preeclampsia in pregnant mothers who smoke by inducing apoptosis of immune cells which may otherwise induce trophoblast apoptosis.

Responsiveness to i.v. immunoglobulin therapy in patients with toxic epidermal necrolysis: A novel pharmaco-immunogenetic concept

Toxic epidermal necrolysis (TEN) represents a rare drug-induced autoimmune reaction with delayed-type hypersensitivity that initiates the process of developing massive keratinocyte apoptosis, dominantly in the dermoepidermal junction. Although the etiopathophysiology has not yet been fully elucidated, the binding of Fas ligand (FasL, CD95L) to the Fas receptor (CD95) was shown to play a key role in the induction of apoptosis in this syndrome. The knowledge of the role of immunoglobulin G (IgG) in inhibition of Fas-mediated apoptosis contributed to the introduction of i.v. Ig (IVIg) in the therapy of TEN patients. Despite great enthusiasm for this therapy at the end of the 1990s, subsequent studies in various populations and meta-analyses could not unequivocally confirm the efficacy of the IVIg-based treatment concept. Today, therefore, we are faced with the dilemmas of how to adjust therapy of TEN patients most effectively, which patients could benefit from IVIg therapy and what dose of the preparation should be administrated. The ground-breaking question is: do the host genetic profiles influence the responsiveness and side-effects of IVIg therapy in TEN patients? Based on recent pharmacological, immunological and genetic findings, we suggest that the variability of IVIg therapy outcomes in TEN patients may be related to functional variants in Fas, FasL and Fc-γ receptor genes. This novel concept could lead to improved quality of care for patients with TEN, facilitating personalized therapy to reduce mortality.

Serum soluble Fas ligand levels and peripheral blood lymphocyte subsets in patients with drug-induced maculopapular rashes, dress, and viral exanthemas

BACKGROUND

Fatty acid synthetase (Fas)/Fas ligand (FasL)-dependent apoptotic pathways have been reported as being involved in the pathogenesis of drug-induced maculopapular rashes.

OBJECTIVE

We investigated serum soluble FasL (sFasL) levels and peripheral blood lymphocyte subtypes to discriminate maculopapular drug eruptions (MPDE) from viral exanthema (VE).

PATIENTS/METHODS

Children with confirmed MPDE (group I), VE (group II), and drug rashes with eosinophilia and systemic symptoms (DRESS) or drug-induced hypersensitivity syndrome (DIHS) (group III) were included. Serum sFasL levels and peripheral blood lymphocyte subtypes were analyzed in groups I-III on admission, and repeated twice (only once for group IV - controls).

RESULTS

There were no significant serum soluble FasL level differences among the groups for all the samples. In the initial samples, CD19⁺ cell numbers in group II were significantly higher than in group IV, and the CD4⁺/CD8⁺ ratio was higher than groups I and IV. In the second samples, CD4⁺ and CD19⁺ cell numbers were significantly higher in group II than group I. In the final samples, CD4⁺ cell numbers in group II were significantly higher than group I and group III. CD19⁺ cells numbers in group III were significantly lower than the other groups for all samples.

CONCLUSION

Serum sFasL levels were not found to be useful in discriminating viral exanthemas from other drug rashes. The significant differences between MPDE, VE, and DRESS were high CD4⁺ and CD19⁺ cell-count numbers in VE but low B-cell numbers in DRESS. This might be important for discriminating VE from DRESS, and the low B-cell count in early symptoms might be a useful predictor of DRESS development.

The Role of Multisystem Disease in Composition of Autologous Serum tears and ocular surface symptom improvement

PURPOSE

Autologous serum tears (AST) contain growth factors and vitamins similar to those in healthy tears and are an effective treatment option for ocular surface disease. This study determined the differences in composition of AST in patients with systemic diseases versus patients with localized ocular surface diseases and the effects on ocular surface symptom improvement.

METHOD

An observational study was performed on 53 patients with either systemic diseases (Group I) or localized ocular surface diseases (Group II) who were prescribed AST. Concentrations of epidermal growth factor (EGF), interleukin 8 (IL-8), fibronectin, vitamin A, and tumor necrosis factor-α (TNF-α) were determined through ELISA assays from patients in both groups. The Ocular Surface Disease Index (OSDI) scores were calculated prior to and 6 weeks after initiation of treatment with AST for new patients.

RESULTS

The average concentration of EGF in Group I (29.39 pg/ml ± 52.85 pg/ml) was significantly lower than in Group II (88.04 pg/ml ±113.75 pg/ml) (p < 0.05). Levels of fibronectin, IL-8, and vitamin A were similar in both groups. There was a 24% reduction in OSDI score 6 weeks after initiation in Group I compared to a 36% reduction reported in Group II (p = 0.065). The OSDI score was reduced significantly after the treatment in all subjects (p = 0.002).

CONCLUSION

Serum tears are a promising therapy for management of ocular surface disease and associated symptoms. The differences between levels of EGF in patients with localized ocular surface disease and systemic inflammatory disease may account for differences in therapeutic outcome.

Presumed Sulfonamide-Associated Uveitis With Stevens-Johnson Syndrome in a Quarter Horse Mare

We describe the case of a four-year-old Quarter Horse mare that presented with fever, respiratory infection with productive cough, disorientation, and bilateral anterior uveitis with discharge that had been previously treated with trimethoprim-sulfadiazine (TMPS). Acinetobacter johnsonii was cultured from an endoscopic tracheal wash. Treatment was initiated with cefquinome, systemic flunixin-meglumine, local ocular atropine, and corticosteroids. On subsequent days, the mare exhibited bilateral edematous, painful swelling of the face, primarily affecting the eyelids and lips. There were neither swellings nor pulsations of the metatarsal arteries. On day five of treatment, the facial swelling disappeared, the uveitis improved markedly, and the mare's periorbital skin, muzzle, and vulva began to slough, revealing underlying, nonpigmented skin. Although systemic use of sulfonamides has been associated with bilateral anterior uveitis and Stevens-Johnson syndrome (SJS or erythema multiforme major) in humans, these conditions are rare in horses. Stevens-Johnson syndrome has been associated most commonly with sulfonamide use but also with a range of other medications, including anti-infectives, anti-inflammatories, anticonvulsants, analgesics, and infections. A possible pathway for sulfonamide-induced SJS is discussed. To our knowledge, this is the first reported case of sulfonamide-associated uveitis and SJS in the horse.

Current Perspectives on Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are considered a delayed-type hypersensitivity reaction to drugs. They represent true medical emergencies and an early recognition and appropriate management is decisive for the survival. SJS/TEN manifest with an "influenza-like" prodromal phase (malaise, fever), followed by painful cutaneous and mucous membrane (ocular, oral, and genital) lesions, and other systemic symptoms. The difference between SJS, SJS/TEN overlap, and TEN is defined by the degree of skin detachment: SJS is defined as skin involvement of < 10%, TEN is defined as skin involvement of > 30%, and SJS/TEN overlap as 10-30% skin involvement. The diagnosis of different degrees of epidermal necrolysis is based on the clinical assessment in conjunction with the corresponding histopathology. The mortality rates for SJS and TEN have decreased in the last decades. Today, the severity-of-illness score for toxic epidermal necrolysis (SCORTEN) is available for SJS/TEN severity assessment. Drugs with a high risk of causing SJS/TEN are anti-infective sulfonamides, anti-epileptic drugs, non-steroidal anti-inflammatory drugs of the oxicam type, allopurinol, nevirapine, and chlormezanone. Besides conventional drugs, herbal remedies and new biologicals should be considered as causative agents. The increased risk of hypersensitivity reactions to certain drugs may be linked to specific HLA antigens. Our understanding of the pathogenesis of SJS/TEN has improved: drug-specific T cell-mediated cytotoxicity, genetic linkage with HLA- and non-HLA-genes, TCR restriction, and cytotoxicity mechanisms were clarified. However, many factors contributing to epidermal necrolysis still have to be identified, especially in virus-induced and autoimmune forms of epidermal necrolysis not related to drugs. In SJS/TEN, the most common complications are ocular, cutaneous, or renal. Nasopharyngeal, esophageal, and genital mucosal involvement with blisters, erosions as well as secondary development of strictures also play a role. However, in the acute phase, septicemia is a leading cause of morbidity and fatality. Pulmonary and hepatic involvement is frequent. The acute management of SJS/TEN requires a multidisciplinary approach. Immediate withdrawal of potentially causative drugs is mandatory. Prompt referral to an appropriate medical center for specific supportive treatment is of utmost importance. The most frequently used treatments for SJS/TEN are systemic corticosteroids, immunoglobulins, and cyclosporine A.

Treatments for Severe Cutaneous Adverse Reactions

Severe cutaneous adverse reaction (SCAR) is life-threatening. It consists of Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN), drug reaction with eosinophilia and systemic symptoms (DRESS), acute generalized exanthematous pustulosis (AGEP), and generalized bullous fixed drug eruptions (GBFDE). In the past years, emerging studies have provided better understandings regarding the pathogenesis of these diseases. These diseases have unique presentations and distinct pathomechanisms. Therefore, theoretically, the options of treatments might be different among various SCARs. However, due to the rarity of these diseases, sufficient evidence is still lacking to support the best choice of treatment for patients with SCAR. Herein, we will provide a concise review with an emphasis on the characteristics and treatments of each SCAR. It may serve as a guidance based on the current best of knowledge and may shed light on the directions for further investigations.

A Review of the Pathogenesis of Toxic Epidermal Necrolysis

Toxic epidermal necrolysis (TEN) is a rare skin condition, most often drug-induced, known for its skin detachment and high mortality. In general, acute TEN is considered a T-cell mediated, type IV hypersensitivity disorder. It mostly results from a cumulative effect of risks from the drug structure, drug metabolism, HLA alleles and T cell clonotypes. However, the precise mechanism of TEN is still unknown. Apoptosis or necroptosis causes keratinocytes to lose their shape and adhesion, and necrosis predominates within a few days. Total epidermal necrosis separates the epidermis from the dermis. TEN is regarded as an immune reaction with predominantly CD8+ T lymphocytes, monocytes/macrophages, and natural killer cells. Impaired regulatory T-cells, T-helper 17 cells, cytotoxic granules such as perforin-granzyme and granulysin, tumor necrosis factor α, annexin, microRNA-18a-5p, and drug metabolites are all thought to be involved. From what is known, it can be assumed their mechanism is complex, and there is still much to be investigated. New findings will contribute to the identification of effective active methods of intervention.

Review of Toxic Epidermal Necrolysis

Toxic epidermal necrolysis (TEN) is a rare but life threatening mucocutaneous reaction to drugs or their metabolites. It is characterised by widespread keratinocyte apoptosis and sloughing of the skin, erosions of the mucous membranes, painful blistering, and severe systemic disturbance. The pathophysiology of TEN is incompletely understood. Historically, it has been regarded as a drug-induced immune reaction initiated by cytotoxic lymphocytes via a human leukocyte antigen (HLA)-restricted pathway. Several mediators have been identified as contributors to the cell death seen in TEN, including; granulysin, soluble Fas ligand, perforin/granzyme, tumour necrosis factor-α (TNF-α), and TNF-related apoptosis-inducing ligand. Currently, granulysin is accepted as the most important mediator of T cell proliferation. There is uncertainty around the accepted management of TEN. The lack of definitive management guidelines for TEN is explained in part by the rarity of the disease and its high mortality rate, which makes it difficult to conduct randomised control trials on emerging therapies. Developments have been made in pharmacogenomics, with numerous HLA alleles identified; however, these have largely been ethnically specific. These associations have translated into screening recommendations for Han Chinese.

Old dog begging for new tricks: current practices and future directions in the diagnosis of delayed antimicrobial hypersensitivity

PURPOSE OF REVIEW

Antimicrobials are a leading cause of severe T cell-mediated adverse drug reactions (ADRs). The purpose of this review is to address the current understanding of antimicrobial cross-reactivity and the ready availability of and evidence for in-vitro, in-vivo, and ex-vivo diagnostics for T cell-mediated ADRs.

RECENT FINDINGS

Recent literature has evaluated the efficacy of traditional antibiotic allergy management, including patch testing, skin prick testing, intradermal testing, and oral challenge. Although patch and intradermal testing are specific for the diagnosis of immune-mediated ADRs, they suffer from drug-specific limitations in sensitivity. The use of ex-vivo diagnostics, especially enzyme-linked immunospot, has been highlighted as a promising new approach to assigning causality. Knowledge of true rates of antimicrobial cross-reactivity aids empirical antibiotic choice in the setting of previous immune-mediated ADRs.

SUMMARY

In an era of increasing antimicrobial resistance and use of broad-spectrum antimicrobial therapy, ensuring patients are assigned the correct 'allergy label' is essential. Re-exposure to implicated antimicrobials, especially in the setting of severe adverse cutaneous reaction, is associated with significant morbidity and mortality. The process through which an antibiotic label gets assigned, acted on and maintained is still imprecise. Predicting T cell-mediated ADRs via personalized approaches, including human leukocyte antigen-typing, may pave future pathways to safer antimicrobial prescribing guidelines.

Immunologic Mediators in Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are a spectrum of T-cell mediated immune disorders. While the contributory mechanisms leading to the apoptosis of epidermal cells in SJS/TEN remain unproven, the keratinocyte apoptosis seen in SJS/TEN is thought to occur through the T-cell mediated Fas-Fas ligand (FasL), perforin/granzyme B, and other immune mediators. Most recently, emphasis has been placed on the granulysin pathway as being the primary mediator of apoptosis and widespread epidermal necrosis in SJS/TEN. This article aims to review the proposed mechanisms by which these pathways work and the immunomodulatory therapies that have been developed in an attempt to target them.

Variable levels of apoptotic signal-associated cytokines in the disease course of patients with Stevens-Johnson syndrome and toxic epidermal necrolysis

BACKGROUND/OBJECTIVES

Keratinocyte death is a hallmark of Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS/TEN). Apoptotic signal-associated cytokines, such as TNF-α, sFasL, granulysin, sTRAIL and IFN-γ have been reported to participate in keratinocyte apoptosis. However, their levels are variable, which hampers the elucidation of the role of these cytokines. We sought to determine whether cytokine levels vary with disease course.

METHODS

The serum cytokine levels of 24 patients and blister fluid of 10 were analysed by enzyme-linked immunosorbent assay on the first day of their admission to hospital and were evaluated at different time points in the disease course. Meanwhile, surface markers (CD3, CD4, CD8, CD1a, CD14, CD16+56 and CD68) of blister fluid cells were measured by flow cytometry.

RESULTS

The concentrations of all cytokines in the serum and blister fluid were higher than those in the controls and were more elevated in the blister fluid than in the serum. Moreover, sTRAIL, IFN-γ and TNF-α quantities were relatively stable, while those of sFasL and granulysin decreased rapidly in the disease course. On the first day, CD8+ T and natural killer cells were predominant in the blister fluid but their relative percentage diminished gradually, while that of CD14+ cells increased.

CONCLUSION

Our study confirmed there are high but variable levels of these cytokines in SJS/TEN, especially in the early phase and different tendencies are manifested in the disease course.

In vitro testing for diagnosis of idiosyncratic adverse drug reactions: Implications for pathophysiology

Idiosyncratic drug reactions (IDRs) represent a major health problem, as they are unpredictable, often severe and can be life threatening. The low incidence of IDRs makes their detection during drug development stages very difficult causing many post-marketing drug withdrawals and black box warnings. The fact that IDRs are always not predictable based on the drug's known pharmacology and have no clear dose-effect relationship with the culprit drug renders diagnosis of IDRs very challenging, if not impossible, without the aid of a reliable diagnostic test. The drug provocation test (DPT) is considered the gold standard for diagnosis of IDRs but it is not always safe to perform on patients. In vitro tests have the advantage of bearing no potential harm to patients. However, available in vitro tests are not commonly used clinically because of lack of validation and their complex and expensive procedures. This review discusses the current role of in vitro diagnostic testing for diagnosis of IDRs and gives a brief account of their technical and mechanistic aspects. Advantages, disadvantages and major challenges that prevent these tests from becoming mainstream diagnostic tools are also discussed here.

Recent advances of pharmacogenomics in severe cutaneous adverse reactions: immune and nonimmune mechanisms

Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and drug reaction with eosinophilia and systemic symptoms (DRESS) are severe cutaneous adverse reactions (SCAR) which are majorly caused by drugs. Though the incidence rate is low, SCAR sometimes can be life-threatening and leads to lifelong sequelae. Many pharmacogenomic associations in immune and nonimmune related genes with the development of SCAR have been discovered recently and the pharmacogenetic tests have been applied to prevent specific drug-induced SCAR. In this review, we discuss the recent advances of pharmacogenomics in SCAR.

Upregulated RIP3 Expression Potentiates MLKL Phosphorylation-Mediated Programmed Necrosis in Toxic Epidermal Necrolysis

Toxic epidermal necrolysis (TEN) is a severe adverse drug reaction involving extensive keratinocyte death in the epidermis. Histologically, the skin from TEN patients exhibits separation at the dermo-epidermal junction and accompanying necrosis of epidermal keratinocytes. Receptor-interacting protein kinase-3 (RIP3 or RIPK3) is an essential part of the cellular machinery that executes "programmed", or "regulated", necrosis and has a key role in spontaneous cell death and inflammation in keratinocytes under certain conditions. Here we show that RIP3 expression is highly upregulated in skin sections from TEN patients and may therefore contribute to the pathological damage in TEN through activation of programmed necrotic cell death. The expression level of mixed lineage kinase domain-like protein (MLKL), a key downstream component of RIP3, was not significantly different in skin lesions of TEN. However, elevated MLKL phosphorylation was observed in the skin from TEN patients, indicating the presence of RIP3-dependent programmed necrosis. Importantly, in an in vitro model of TEN, dabrafenib, an inhibitor of RIP3, prevented RIP3-mediated MLKL phosphorylation and decreased cell death. Results from this study suggest that the high expression of RIP3 in keratinocytes from TEN patients potentiates MLKL phosphorylation/activation and necrotic cell death. Thus, RIP3 represents a potential target for treatment of TEN.

Towards the development of mechanism-based biomarkers to diagnose drug hypersensitivity

T-cells are activated by different mechanisms in the presence of drugs, metabolites or haptens, and they release several molecules that can be used in the diagnosis of drug hypersensitivity.

Immunological response in Stevens-Johnson syndrome and toxic epidermal necrolysis

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are life-threatening cutaneous adverse drug reactions that induce widespread epidermal necrosis. Recent advances in pharmacogenomic studies have provided evidence of genetic predispositions to SJS/TEN. Several concepts have been proposed to explain the pathogenesis of severe cutaneous adverse drug reactions. In the hapten concept, small molecules called haptens elicit an immune response only when attached to proteins. The "p-i" concept postulates that the causative drugs can stimulate cells by binding directly and reversibly to immune receptors. In addition, there is the idea that drugs alter the antigen by binding to the human leukocyte antigen pocket. With regard to keratinocyte death, several cell death mediators, such as FasL, granulysin and annexin A1, have been proposed as playing a role in SJS/TEN pathogenesis. A subset of T lymphocytes, including regulatory T cells, also may play a role in SJS/TEN.

Regulation of TRAIL-receptor expression by the ubiquitin-proteasome system

The tumor necrosis factor (TNF)-related apoptosis-inducing ligand- receptor (TRAIL-R) family has emerged as a key mediator of cell fate and survival. Ligation of TRAIL ligand to TRAIL-R1 or TRAIL-R2 initiates the extrinsic apoptotic pathway characterized by the recruitment of death domains, assembly of the death-inducing signaling complex (DISC), caspase activation and ultimately apoptosis. Conversely the decoy receptors TRAIL-R3 and TRAIL-R4, which lack the pro-apoptotic death domain, function to dampen the apoptotic response by competing for TRAIL ligand. The tissue restricted expression of the decoy receptors on normal but not cancer cells provides a therapeutic rational for the development of selective TRAIL-mediated anti-tumor therapies. Recent clinical trials using agonistic antibodies against the apoptosis-inducing TRAIL receptors or recombinant TRAIL have been promising; however the number of patients in complete remission remains stubbornly low. The mechanisms of TRAIL resistance are relatively unexplored but may in part be due to TRAIL-R down-regulation or shedding of TRAIL-R by tumor cells. Therefore a better understanding of the mechanisms underlying TRAIL resistance is required. The ubiquitin-proteasome system (UPS) has been shown to regulate TRAIL-R members suggesting that pharmacological inhibition of the UPS may be a novel strategy to augment TRAIL-based therapies and increase efficacies. We recently identified b-AP15 as an inhibitor of proteasome deubiquitinase (DUB) activity. Interestingly, exposure of tumor cell lines to b-AP15 resulted in increased TRAIL-R2 expression and enhanced sensitivity to TRAIL-mediated apoptosis and cell death in vitro and in vivo. In conclusion, targeting the UPS may represent a novel strategy to increase the cell surface expression of pro-apoptotic TRAIL-R on cancer cells and should be considered in clinical trials targeting TRAIL-receptors in cancer patients.

Erythema multiforme, Stevens-Johnson syndrome and toxic epidermal necrolysis: a comparative review

BACKGROUND

Human erythema multiforme (EM) and Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) are separate conditions. There is no consensus on classification criteria for the eponymous diseases in animals.

RESULTS

Animal EM is very different from 90% of human EM, which is herpes virus associated (HAEM). Animals lack acrally distributed, typical raised targets. Unlike canine parvovirus 'EM', HAEM is not an active infection. Animal EM is often attributed to drugs, but this is rarely proved. Conversely, human and animal SJS/TEN are almost identical, life-threatening disorders of epidermal necrosis and detachment, typically triggered by drugs (occasionally by infectious agents). Both EM and SJS/TEN are mediated by cytotoxic lymphocyte responses against altered keratinocytes (infectious agents or drugs). Apoptosis results from direct cytotoxicity or through soluble mediators, namely Fas ligand, granzymes, perforin and granulysin. Diagnosis in humans is clinicopathological, with emphasis on clinical lesions; histopathology confirms the pathological process as interface (cytotoxic) dermatitis. Human EM is self-limiting; only recurrent and rare persistent cases require antiviral/immunosuppressive therapies. Drug-induced EM responds to drug withdrawal. Idiopathic canine EM (>40%) is usually chronic, refractory to treatment and may represent heterogeneous conditions. Early identification and removal of the causative drug and high-quality supportive care are critical in SJS/TEN. Mortality rate is nevertheless high.

CONCLUSIONS AND CLINICAL IMPORTANCE

(1) Histopathological lesions do not reliably differentiate EM, SJS and TEN. (2) A multicentre study to develop a consensus set of clinical criteria for EM and SJS/TEN in animals is overdue. (3) No adjunctive therapies, including intravenous immunoglobulin and ciclosporin, have met evidence-based standards.

Fatal case of cephalexin-induced toxic epidermal necrolysis

Purpose:

To describe a case of toxic epidermal necrolysis likely caused by cephalexin with a review of the literature.

Case:

An 80-year-old male with a known allergy to cephalosporins, residing at a long-term acute care hospital, received cephalexin for a urinary tract infection. And 1 day after starting therapy, the patient developed an extensive erythematous rash accompanied by skin sloughing; 4 days after receiving cephalexin, the patient was directly admitted to the burn intensive care unit and was diagnosed with toxic epidermal necrolysis involving 56% of the total body surface area. Progressive deterioration to multisystem organ failure ensued, and the patient died 5 days following his admission to the burn intensive care unit. At the time of death, ulcerations were noted over approximately 80% of his body.

Summary:

The temporal association of the patient’s ingestion of cephalexin for a urinary tract infection to his onset of toxic epidermal necrolysis suggests that this 80-year-old man developed toxic epidermal necrolysis following the administration of cephalexin for a urinary tract infection.

Clinical features and prognostic factors in severe cutaneous drug reactions

BACKGROUND

Severe cutaneous adverse reactions (SCARs) include Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and drug reaction with eosinophilia and systemic symptoms (DRESS). SJS and TEN (SJS/TEN) and DRESS are thought to be different diseases; however, they share some clinical and laboratory features. Although SCORTEN serves as an excellent prognostic marker for SJS/TEN, there is still a need for development of other prognostic markers for SCARs.

METHODS

The study population consisted of 88 SCAR patients. Clinical characteristics and clinical manifestations were compared between SJS/TEN and DRESS. Risk factor analyses for prolonged hospitalization were performed.

RESULTS

Of the 88 patients, 41 were SJS/TEN and 47 were DRESS. Mortality rates of TEN and DRESS were 9.8 and 2.1%, respectively. Allopurinol and carbamazepine were the most common causes of both SJS/TEN and DRESS (34.7 and 62.9%, respectively). Some of the systemic presentations, such as fever and laboratory abnormalities were common in both phenotypes. Thrombocytopenia tended to be related to prolonged hospitalization (longer than 3 weeks) in SJS/TEN (odds ratio, OR = 5.1, 95% confidence interval, CI 0.8-31.8, p = 0.076). In DRESS patients, leukocytosis at presentation (OR 4.8, 95% CI 1.1-20.3, p = 0.03) was related to prolonged hospitalization.

CONCLUSIONS

Clinical features of SCARs in a tertiary hospital in Korea were similar to those reported previously. SJS/TEN and DRESS shared some clinical and laboratory features. Thrombocytopenia for SJS/TEN and leukocytosis at presentation for DRESS may be useful prognostic markers for prolonged hospitalization.

Toxic epidermal necrolysis: Part II. Prognosis, sequelae, diagnosis, differential diagnosis, prevention, and treatment

Toxic epidermal necrolysis (TEN) is a life-threatening, typically drug-induced, mucocutaneous disease. TEN has a high mortality rate, making early diagnosis and treatment of paramount importance. New but experimental diagnostic tools that measure serum granulysin and high-mobility group protein B1 (HMGB1) offer the potential to differentiate early TEN from other, less serious drug reactions, but these tests have not been validated and are not readily available. The mainstay of treatment for TEN involves discontinuation of the offending drug, specialized care in an intensive care unit or burn center, and supportive therapy. Pharmacogenetic studies have clearly established a link between human leukocyte antigen allotype and TEN. Human leukocyte antigen testing should be performed on patients of East Asian descent before the initiation of carbamezapine and on all patients before the initiation of abacavir. The effectiveness of systemic steroids, intravenous immunoglobulins, plasmapheresis, cyclosporine, biologics, and other agents is uncertain.

Phenobarbital induced Stevens-Johnson syndrome in a child

Phenobarbital, an antiepileptic agent has numerous adverse reactions including Stevens– Johnson syndrome (SJS), a rare medical emergency. A 12-year-old male epileptic child with phenobarbital-induced SJS was referred for the management of severe pain in relation to extensively decayed molar tooth and oral mucosal ulcerations. The patient was managed by withdrawal of phenobarbital and palliative treatment of the lesions.

Effect of age and early intervention with a systemic steroid, intravenous immunoglobulin or amniotic membrane transplantation on the ocular outcomes of patients with Stevens-Johnson syndrome

PURPOSE

This retrospective observational case series of fifty-one consecutive patients referred to the eye clinic with acute-stage Stevens-Johnson syndrome (SJS) or toxic epidermal necrolysis (TEN) from 1995 to 2011 examines the effect of early treatment with a systemic corticosteroid or intravenous immunoglobulin (IVIG) on the ocular outcomes in patients with SJS or TEN.

METHODS

All patients were classified by age (≤18 years vs. >18 years) and analyzed by treatment modality and early intervention with systemic corticosteroids (≤5 days), IVIG (≤6 days), or amniotic membrane graft transplantation (AMT) (≤15 days). The main outcomes were best-corrected visual acuity (BCVA) in logarithm of the minimum angle of resolution (logMAR) and ocular involvement scores (OIS, 0-12), which were calculated based on the presence of superficial punctate keratitis, epithelial defect, conjunctivalization, neovascularization, corneal opacity, keratinization, hyperemia, symblepharon, trichiasis, mucocutaneous junction involvement, meibomian gland involvement, and punctal damage.

RESULTS

The mean logMAR and OIS scores at the initial visit were not significantly different in the pediatric group (logMAR = 0.44, OIS = 2.76, n = 17) or the adult group (logMAR = 0.60, OIS = 2.21, n = 34). At the final follow-up, the logMAR and OIS had improved significantly in the adult group (p = 0.0002, p = 0.023, respectively), but not in the pediatric group. Early intervention with IVIG or corticosteroids significantly improved the mean BCVA and OIS in the adult group (p = 0.043 and p = 0.024, respectively for IVIG; p = 0.002 and p = 0.034, respectively for corticosteroid). AMT was found to be associated with a significantly improved BCVA or OIS in the late treatment group or the group with a better initial OIS (p = 0.043 and p = 0.043, respectively for BCVA; p = 0.042 and p = 0.041, respectively for OIS).

CONCLUSIONS

Our findings suggest that patients with SJS or TEN who are aged 18 years or less have poorer ocular outcomes than older patients and that early treatment with steroid or immunoglobulin therapy improves ocular outcomes.

Drug-induced severe adverse reaction enhanced by human herpes virus-6 reactivation

Reactivation of certain latent viruses has been linked with a more severe course of drug-induced hypersensitivity reaction (HSR). For example, reactivation of human herpes virus (HHV)-6 is associated with severe organ involvement and a prolonged course of disease. The present study discusses an HSR developed in a previously healthy male exposed to ceftriaxone, doxycycline, vancomycin, and trimethoprim/sulfamethoxazole (co-trimoxazole; TMP/SMX). Initially, the patient presented clinical manifestations of HSR, as well as clinical and laboratory measurements compatible with liver and renal failure. Moreover, the patient presented skin desquamation compatible with Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis. During the reaction, it was observed HHV-6 reactivation. The severity of clinical symptoms is correlated with HHV-6 titer, as well as with results of the in vitro lymphocyte toxicity assay (LTA). Serum levels of a large panel of cytokines are compared between the patient, a large population of SJS patients, and a cohort of healthy controls, using data collected by our laboratory over the years. HHV-6 was measured in the cell culture media from lymphocytes incubated with each of the 4 drugs. Moreover, we describe a new assay using cytokines released by patient lymphocytes following in vitro exposure to the incriminated drugs as biomarkers of HSR. Based on LTA results, HHV-6 reactivation and cytokine measurements, we establish that only doxycycline and TMP/SMX were involved in the HSR. As result of this analysis, the patient could continue to use the other 2 antibiotics safely.

Acute blistering diseases on the burn ward: Beyond Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis

OBJECTIVE

Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis are on a spectrum of rare reactions primarily attributable to drugs. Timely diagnosis, cessation of the offending drug and burn center care are associated with favorable outcomes. Acute blistering disease has a wide differential diagnosis, including autoimmune bullous disease and other drug reactions. The aim of our study was to identify the final diagnosis in patients transferred for widespread blistering disease and to identify clinical features at admission predicting final diagnosis.

METHODS

We performed a 5-year retrospective chart review (2006-2011) of the clinical features at admission of patients transferred to a burn ward with widespread blistering disease. Clinical features at admission were compared between patients.

RESULTS

12 patients had a final diagnosis of Stevens-Johnson Syndrome or Toxic Epidermal Necrolysis and 7 patients had an alternative final diagnosis. Skin detachment surface area at admission was superior in the Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis group. Presence of tense bullae and pustules was associated with an alternative final diagnosis.

CONCLUSION

Extensive skin detachment surface and morphological features (tense bullae, pustules) were statistically significant clinical clues to final diagnosis. Patients transferred for widespread blistering disease should be thoroughly evaluated in order to exclude other causes of acute blistering disease.

Overview of penicillin allergy

Allergy to penicillin is the most commonly reported antibiotic allergy. However, most patients who report a positive history of a prior reaction to penicillin are not found to be allergic to penicillin upon skin testing. Often, this history is vague or based on a parent's recollection of an event that occurred in the distant past. Avoidance of penicillin based on self-reported allergic history alone often leads to the use of an alternate antibiotic with greater cost or side effect profile. Patients with a negative skin test to both major and minor determinants may generally be given penicillin, with a statistical risk of developing an allergic reaction similar to that observed in the general population. A more cautious approach in these cases where the degree of suspicion is low, an allergic etiology is unproven, or there is a negative skin test, is to do a graded challenge. If the skin test is positive, an alternate antibiotic should be used. If, however, an alternate antibiotic is not available, then desensitization may be performed, but there are limitations to desensitization as well, and tolerance is not permanent. Avoidance of cephalosporins may be recommended in cases of penicillin allergy, but newer generation cephalosporins have demonstrate less cross-reactivity to penicillin than earlier generation ones. Desensitization protocols for cephalosporins are available but not standardized. The mechanisms of antibiotic sensitization are not clearly understood.