Making a diagnosis in severe cutaneous drug hypersensitivity reactions

High risk and low prevalence diseases: Stevens Johnson syndrome and toxic epidermal necrolysis

INTRODUCTION

Stevens Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are serious conditions that carry a high rate of morbidity and mortality.

OBJECTIVE

This review highlights the pearls and pitfalls of SJS/TEN, including presentation, diagnosis, and management in the emergency department (ED) based on current evidence.

DISCUSSION

SJS/TEN is a rare, delayed hypersensitivity reaction resulting in de-epithelialization of the skin and mucous membranes. The majority of cases are associated with medication or infection. Clinicians should consider SJS/TEN in any patient presenting with a blistering mucocutaneous eruption. Evaluation of the skin, mucosal, pulmonary, renal, genital, and ocular systems are essential in the diagnosis of SJS/TEN, as well as in the identification of complications (e.g., sepsis). Laboratory and radiological testing cannot confirm the diagnosis in the ED setting, but they may assist in the identification of complications. ED management includes stabilization of airway and breathing, fluid resuscitation, and treatment of any superimposed infections with broad-spectrum antibiotic therapy. All patients with suspected SJS/TEN should be transferred and admitted to a center with burn surgery, critical care, dermatology, and broad specialist availability.

CONCLUSIONS

An understanding of SJS/TEN can assist emergency clinicians in diagnosing and managing this potentially deadly disease.

Challenging dogmas: Intravenous versus oral beta-lactam antibiotic provocation tests

Background

Drug provocation tests (DPT) are considered the gold standard procedure to ascertain the diagnosis of beta-lactam (BL) allergy. Regarding route of administration, current recommendations prioritize oral challenges, considering them safer, and reserving the intravenous route for drugs for which this is the only formulation.

Objective

To compare in terms of tolerance and safety two protocols of BL DPT, using an oral protocol (OR-DPT) and an intravenous protocol (IV-DPT).

Methods

A descriptive, retrospective study was performed, including adult patients who underwent IV-DPT or OR-DPT for suspected immediate or delayed hypersensitivity to BL antibiotics, over a period of 4 years (between January 2018 and December 2021). Demographical data, index hypersensivity reactions' characteristics and tolerance to DPT were reviewed.

Results

A total of 1036 patients underwent DPT, mean age of 56.8 (standard deviation, SD, 17.8) years, 655 were women (63.2%). Immediate drug hypersensitivity reactions (DHR) had occurred in 564 of patients (54.4%). OR-DPT were performed in 439 (42.4%) and IV-DPT in 597 (57.6%). The frequency of reactions during DPT, regardless of the route used, was low (3.6%): only 16 (3.6%) in OR-DPT and 21 (3.5%) in IV-DPT. From IV-DPT, 16 out 21 DHR during DPT were immediate compared with 4 out of 16 in OR-DPT. Adjusted relative risk of developing a hypersensitivity reaction during IV-DPT versus OR-DPT was 1.13 (95% confidence interval (CI)0.57-2.22).

Conclusion

The results suggest that OR-DPT and IV-DPT are both safe procedures when adequately performed. However, IV-DPT protocols showed a higher rate of immediate DHR during DPT probably due to the selection of basal high-risk patients to undergo IV-DPT. In conclusion, IV-DPT may be considered as an option for challenges in drug-allergy studies, entailing a precise administration.

Severe cutaneous adverse reactions due to antibiotics therapy: a pharmacovigilance analysis of FDA adverse event reporting system events

BACKGROUND

The aim of this study was to monitor, identify and evaluate severe cutaneous adverse reactions (SCAR) induced by antibiotics in patients.

METHODS

Disproportionality algorithms were performed in data mining to screen suspected SCAR after using nine categories of antibiotics based on the FDA's Adverse Event Reporting System (FAERS) from January 2004 to December 2022. The drug information and demographic characteristics of antibiotic-associated SCAR were also investigated.

RESULTS

The FAERS database received 12,212 antibiotic-associated SCAR cases. Approximately half of the SCAR patients were females, the majority of them were adults aged 18-65 years (48.35%), and 47.68% of SCAR patients required hospitalization. The highest SCAR signals RORs (95% CI) for antibiotics were: sulfonamides 23.30 (22.05-24.62), glycopeptides 21.27 (20.26-22.33), penicillins 16.00 (15.44-16.59), carbapenems 10.46 (9.57-11.44), and cephalosporins 13.27 (12.57-14.00). Cefotaxime, sulfamethoxazole/trimethoprim, cefixime, vancomycin, piperacillin, ceftriaxone, amoxicillin, and meropenem had stronger associations with the SCAR than the other antibiotics. However, sulfonamides-associated SCAR cases had the lowest fatality rate (6.23%), penicillin-associated SCAR cases had the highest hospitalization rate (54.16%), and carbapenem-associated SCAR cases seemingly resulted in the highest risk of death (19.03%).

CONCLUSION

Data mining of FAERS identified 30 antibiotic-associated SCAR signals, and provided a referable evidence of the occurrence, characteristics and prognosis of antibiotic-related SCARs.

Severe cutaneous adverse reactions to drugs: A real-world pharmacovigilance study using the FDA Adverse Event Reporting System database

Background: Sound drug safety information is important to optimize patient management, but the widely recognized comprehensive landscape of culprit-drugs that cause severe cutaneous adverse reactions (SCARs) is currently lacking.

Objective: The main aim of the study is to provide a comprehensive landscape of culprit-drugs for SCARs to guide clinical practice.

Methods: We analyzed reports associated with SCARs in the FDA Adverse Event Reporting System database between 1 January 2004 and 31 December 2021 and compiled a list of drugs with potentially serious skin toxicity. According to this list, we summarized the reporting proportions of different drugs and drug classes and conducted disproportionality analysis for all the drugs. In addition, the risk characteristic of SCARs due to different drugs and drug classes was summarized by the positive–negative distribution based on the results of the disproportionality analysis.

Results: A total of 77,789 reports in the FDA Adverse Event Reporting System database were considered SCAR-related, of which lamotrigine (6.2%) was the most reported single drug followed by acetaminophen (5.8%) and allopurinol (5.8%) and antibacterials (20.6%) was the most reported drug class followed by antiepileptics (16.7%) and antineoplastics (11.3%). A total of 1,219 drugs were reported as culprit-drugs causing SCARs in those reports, and the largest number of drugs belonged to antineoplastics. In disproportionality analysis, 776 drugs showed at least one positive pharmacovigilance signal. Drugs with the most positive signals were lamotrigine, acetaminophen, furosemide, and sulfamethoxazole/trimethoprim.

Conclusion: Our study provided a real-world overview of SCARs to drugs, and the investigation of SCAR positive–negative distribution across different drugs revealed its risk characteristics, which may help optimize patient management.

Utility and Safety of Skin Tests in Drug Reaction With Eosinophilia and Systemic Symptoms (DRESS): A Systematic Review

BACKGROUND

Determination of culprit drug in drug reaction with eosinophilia and systemic symptoms (DRESS) is crucial. Skin tests have been used, although it remains unclear how sensitive these are.

OBJECTIVE

To determine the value of skin tests in the assessment of drug causality in DRESS.

METHODS

A systematic literature search was conducted for publications from 1996 onward of skin tests (skin prick test = SPT, patch test = PT, intradermal test = IDT) performed in clearly defined DRESS cases. Outcomes of testing, drug culpability assessments, and challenge test data were extracted.

RESULTS

A total of 17 articles met inclusion criteria. In 290 patients with DRESS, patch testing was most frequent (PT = 97.2% [n = 282], IDT = 12.4% [n = 36], SPT = 3.1% [n = 9]). Positive results were noted in 58.4% (n = 160 of 282) of PTs, 66.5% of IDTs, and 25% of SPTs. When confidence of drug causality was high (n = 73 of 194), testing did not correlate well with clinical suspicion: PTs, 37.6%; IDTs, 36.5%. Direct comparison of skin testing with provocation testing (n = 12) showed 83.3% correlation. Positive IDT results were reported in 8 negative PT cases.

CONCLUSIONS

Skin tests, particularly PTs and IDTs, have been reported as tools for diagnosis of causal drugs in DRESS. Heterogeneity in methodology, results analysis, and reporting of cohorts make meta-analysis to determine sensitivity and specificity of published literature impossible and highlight weaknesses in the field. We propose that international collaboration is essential to harmonize the methodology and reporting measures from hypersensitivity testing studies in larger cohorts.

Antiepileptic drug-induced hypersensitivity syndrome with liver function abnormality and fever as the first manifestation: A case report

RATIONALE

Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is a severe cutaneous drug reaction characterized by fever, lymphadenopathy, hematologic abnormalities, single or multiple organ involvement, and viral reactivation.[1] The most frequently reported offending drugs are aromatic antiepileptic agents, antibiotics, and allopurinol.[2] Though a relatively rare syndrome, DRESS can lead to severe multi-organ system dysfunction, and in some cases even death. DRESS is one of the severe drug eruptions in dermatological diseases, but it is difficult to diagnose for internist. In this paper, a typical drug hypersensitivity syndrome with abnormal liver function and fever as the first manifestations was reported. The objective of this study was to improve the understanding of rare drug hypersensitivity syndrome in digestion and other fields, and to avoid missed diagnosis and misdiagnosis.

PATIENT CONCERNS

A 33-year-old Chinese female was initially diagnosed with acute hepatic insufficiency. Combined with the suspicious drug history, she developed DRESS with fever, target erythema, left lymph node enlargement, hematological abnormalities, and abnormal liver function.

DIAGNOSES

Combined with the above characteristics, liver toxicity is the main manifestation, accompanied by fever, mainly moderate to high fever (above 38 °C) , sporadic rash, other organs (kidney, immune system) damage, and a marked increase in eosinophil granulocytic. Therefore the patient was diagnosed with definite case of DRESS syndrome based on clinical and laboratory findings.

INTERVENTIONS

Hormones (methylprednisolone 60 mg/day for 12 days and 80 mg/day for 12 days) and immunoglobulins (intravenous immunoglobulin 10 g/day for 5 days and 20 g/day for 7 days) were given.

OUTCOMES

The patient was discharged from the hospital after recovery. One month after discharge, she was re-admitted to the hospital because of elevated blood sugar and was diagnosed as diabetes.

LESSONS

DRESS syndrome is a rare but life-threatening hypersensitivity reaction. The mortality will be very high if it's not diagnosed and treated timely. This paper presents a successful case of methylprednisolone plus intravenous immunoglobulin therapy, which provides a stronger evidence for the future diagnosis and treatment of the disease.

LTT and HLA testing as diagnostic tools in Spanish vancomycin-induced DRESS cases: A case-control study

Drug reaction with eosinophilia and systemic symptoms (DRESS) is a severe T-cell-mediated off-target adverse reaction. DRESS cases caused by vancomycin have often been reported. The HLA-A*32:01 allele has been associated with genetic susceptibility to vancomycin-induced DRESS in US citizens of European descent. We have analyzed the association of the HLA-A*32:01 allele in 14 Spanish DRESS cases in which vancomycin was suspected as the culprit drug, and the lymphocyte transformation test (LTT) as an in vitro assay to evaluate vancomycin sensitization. The results were compared to vancomycin-tolerant control donors. LTT was performed in 12 DRESS cases with PBMCs from resolution samples available and in a group of 12 tolerant donors. ROC curves determined that LTT is a suitable tool to identify patients sensitized to vancomycin (AUC = 0.9646; p < 0.0001). When a stimulation index >3 was regarded as a positive result, contingency tables determined 91% sensitivity, 91.67% specificity, 91% positive predictive value, and 91.67% negative predictive value (p = 0.0001, Fisher’s exact test). The HLA A*32:01 allele was determined by an allele-specific PCR assay in 14 cases and 25 tolerant controls. Among the DRESS cases, five carriers were identified (35.7%), while it was detected in only one (4%) of the tolerant donors, [odds ratio (OR) = 13.33; 95% CI: 1.364–130.3; p = 0.016]. The strength of the association increased when only cases with positive LTT to vancomycin were considered (OR = 24.0; 95% CI: 2.28–252.6; p = 4.0 × 10⁻³). Our results confirm the association of the risk allele HLA-A*32:01 with vancomycin-induced DRESS in Spanish cases, and support LTT as a reliable tool to determine vancomycin sensitization.

Potential Biomarker Identification by RNA-seq analysis in Antibiotic-related Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS): a Pilot Study

One of the most severe forms of cutaneous adverse drug reactions is 'drug reaction with eosinophilia and systemic symptoms' (DRESS), hence subsequent avoidance of the causal drug is imperative. However, attribution of drug culpability in DRESS is challenging and standard skin allergy tests are not recommended due to patient safety reasons. Whilst incidence of DRESS is relatively low, between 1:1000 to 1:10,000 drug exposures, antibiotics are a commoner cause of DRESS and absence of confirmatory diagnostic test can result in unnecessary avoidance of efficacious treatment. We therefore sought to identify potential biomarkers for development of a diagnostic test in antibiotic-associated DRESS. Peripheral blood mononuclear cells (PBMCs) from a 'discovery' cohort (n = 5) challenged to causative antibiotic or control were analysed for transcriptomic profile. A panel of genes was then tested in a validation cohort (n = 6) and compared to tolerant controls and other inflammatory conditions which can clinically mimic DRESS. A scoring system to identify presence of drug hypersensitivity was developed based on gene expression alterations of this panel. The DRESS transcriptomic panel identified antibiotic-DRESS cases in a validation cohort but was not altered in other inflammatory conditions. Machine learning or differential expression selection of a biomarker panel consisting of six genes (STAC, GPR183, CD40, CISH, CD4, and CCL8) showed high sensitivity and specificity (100% and 85.7-100% respectively) for identification of the culprit drug in these cohorts of antibiotic-associated DRESS. Further work is required to determine whether the same panel can be repeated for larger cohorts, different medications, and other T cell mediated drug hypersensitivity reactions.

Histopathologic Features of Maculopapular Drug Eruption

Background: Cutaneous adverse drug reaction (CADR) is common in both inpatient and outpatient clinical settings and has been associated with a large variety of medications. Drug reactions represent a significant burden to the healthcare system due to increased hospital stay durations and associated costs. Moreover, some of these reactions may be life-threatening. The most common clinical manifestation of a CADR is a maculopapular drug eruption (MDE). Due to its many clinical mimics and associations with a variety of histopathologic patterns, maculopapular drug eruption is difficult to definitively diagnose from both a clinical and histopathological perspective. Summary: We reviewed the clinical and histopathologic features of 327 cases of MDE from several studies in the literature and summarized characteristic histopathologic findings and their frequencies of occurrence. We found that the most common and suggestive histopathologic features of MDE were epidermal spongiosis, lymphocytic infiltrate, and occasional necrotic keratinocytes; interface change at the DEJ; superficial perivascular and interstitial lymphocytic infiltrate with or without eosinophils and neutrophils in the mid-to-deep dermis and mild papillary dermal edema; and dilation of superficial vessels. The presence of multiple histopathologic patterns within the same tissue specimen is also suggestive of MDE. This review and analysis suggest that a biopsy may improve the diagnostic accuracy by both establishing common and uncommon features associated with MDE and reviewing features that help to exclude other causes of maculopapular eruption. Key Message: Histopathologic criteria for the diagnosis of MDE, while not entirely specific, may aid in establishing a differential that includes a drug eruption. Thus, a biopsy can be a helpful diagnostic tool when MDE is suspected by demonstrating findings suggestive of MDE or by ruling out clinical mimics. However, biopsy results cannot be used in isolation as clinical-pathologic correlation is paramount in MDE.

Patch testing in Drug reaction with eosinophilia and systemic symptoms (DRESS): a literature review

The literature on positive patch test results in drug reaction with eosinophilia and systemic symptoms (DRESS) is reviewed. 105 drugs were identified that have together caused 536 positive patch tests in 437 patients suffering from DRESS. By far most reactions (n=145) were caused by carbamazepine, followed by amoxicillin, isoniazid, phenytoin, ethambutol, fluindione, phenobarbital, rifampicin, and ceftriaxone; 43 drugs each caused a single case only. The drug classes causing the highest number of reactions are anticonvulsants (39%), beta-lactam antibiotics (20%), antituberculosis agents (11%), non-beta-lactam antibiotics (6%) and iodinated contrast media (5%). The sensitivity of patch testing (percentage of positive reactions) is high for anticonvulsants (notably carbamazepine), beta-lactam antibiotics (notably amoxicillin) and possibly iodinated contrast media. Allopurinol and sulfasalazine frequently cause DRESS, but never give positive patch tests. Patch testing in DRESS appears to be safe, although mild recurrence of DRESS symptoms, mostly skin reactions, may not be rare. Multiple drug hypersensitivity was found to occur in 16% of all patients, but it is argued that the true frequency is (far) higher. Clinical aspects of DRESS, including diagnosing the disease and identifying culprit drugs (patch tests, intradermal tests, in vitro tests, challenge tests) are also provided, emphasizing the role of patch testing. This article is protected by copyright. All rights reserved.

Results of patch testing in Acute generalized exanthematous pustulosis (AGEP): a literature review

The literature on positive patch test results in acute generalized exanthematous pustulosis (AGEP) is reviewed. 93 drugs were identified that have together caused 259 positive patch tests in 248 patients suffering from AGEP. The drug classes causing the highest number of reactions are beta-lactam antibiotics (25.9%), other antibiotics (20.8%), iodinated contrast media (7.3%) and corticosteroids (5.4%), together accounting for nearly 60% of all reactions. The highest number of reactions to individual drugs was to amoxicillin (n=36), followed by pristinamycin (n=25), diltiazem (n=14), amoxicillin-clavulanic acid (n=13), clindamycin (n=11) and iomeprol (n=8); 59 of the 93 drugs each caused a single case only. The "Top-10" drugs together caused over 50% of all reactions. The sensitivity of patch testing (percentage of positive reactions) in patients with AGEP is largely unknown, but may generally be around 50%, which also applies to pristinamycin. Patch testing in AGEP appears to be safe, although mild recurrence of AGEP skin symptoms or other rashes may occur occasionally. Clinical aspects of AGEP, including epidemiology, etiology and pathophysiology, clinical features, histology, treatment, and prognosis are briefly presented, as are diagnosing the disease and identifying the culprit drugs with patch tests, intradermal tests, in vitro tests, and challenge tests. This article is protected by copyright. All rights reserved.

Lab-Based Culprit Drug Identification Methods for Cutaneous Drug Eruptions: A Scoping Review

BACKGROUND

Identification of culprit drugs when managing cutaneous drug eruptions is essential. Causality assessment methods (CAMs) have been proposed, including lab-based techniques. However, no consensus guidelines exist.

OBJECTIVES

To identify and map the functionality and feasibility of lab-based CAMs.

METHODS

A scoping review was conducted to identify culprit drug identification methods. Publications on lab-based methods were analyzed. Medline, Embase, and Cochrane Central Register of Controlled Trials databases were searched.

RESULTS

Twenty-five publications met inclusion criteria. Nine lab-based CAMs were studied, including lymphocyte transformation test, cytokine measurement (ELISpot, ELISA, beads array assay), modified IFN-ɣ ELISpot, CellScan, histamine release, granzyme B-ELISpot, intracellular granulysin, lymphocyte toxicity assay, and HLA allele genotyping. Diagnostic accuracy was reported for 8/9 methods. Clinical assessment and operational algorithms were commonly used as validation benchmarks. Lab-based methods were assessed at different phases of a drug eruption including in the acute (18.1%), recovery (27.3%), acute and recovery (27.3%), or an unspecified phase (27.3%). Lymphocyte transformation test (specificity 30% to 100%, sensitivity 27% to 73%) and cytokine measurement (specificity 76% to 100%, sensitivity 20% to 84%) were the most common methods studied.

CONCLUSIONS

Lab-based CAMs can be low-risk, effective, and complementary of clinical methods. High-quality studies are needed to adequately develop and validate these tools for clinical practice.

Patch Testing in Drug Eruptions: Practical Aspects and Literature Review of Eruptions and Culprit Drugs

ABSTRACT

There is overwhelming evidence that many delayed cutaneous adverse drug reactions (beginning >6 hours after drug intake) are mediated by delayed-type (type IV) hypersensitivity, including maculopapular eruptions, erythroderma, symmetrical drug-related intertriginous and flexural exanthema/baboon syndrome, eczematous eruptions, fixed drug eruptions, acute generalized exanthematous pustulosis, and drug reaction with eosinophilia and systemic symptoms/drug-induced hypersensitivity syndrome. Therefore, after resolution of the reaction, patch tests should be performed as first diagnostic method to identify the culprit drug(s). This article provides tools to perform drug patch tests properly and safely, discussing clinical history, indications, procedure, drug patch test materials, sensitivity, the meaning of negative patch tests, and safety of the procedure. In addition, a literature review of eruptions and culprit drugs is provided in tabular format.

Drug triggered pruritus, rash, papules, and blisters - is AGEP a clash of an altered sphingolipid-metabolism and lysosomotropism of drugs accumulating in the skin?

Rash, photosensitivity, erythema multiforme, and the acute generalized exanthematous pustulosis (AGEP) are relatively uncommon adverse reactions of drugs. To date, the etiology is not well understood and individual susceptibility still remains unknown. Amiodarone, chlorpromazine, amitriptyline, and trimipramine are classified lysosomotropic as well as photosensitizing, however, they fail to trigger rash and pruritic papules in all individuals. Lysosomotropism is a common charcteristic of various drugs, but independent of individuals. There is evidence that the individual ability to respond to external oxidative stress is crosslinked with the elongation of long-chain fatty acids to very long-chain fatty acids by ELOVLs. ELOVL6 and ELOVL7 are sensitive to ROS induced depletion of cellular NADPH and insufficient regeneration via the pentose phosphate pathway and mitochondrial fatty acid oxidation. Deficiency of NADPH in presence of lysosomotropic drugs promotes the synthesis of C16-ceramide in lysosomes and may contribute to emerging pruritic papules of AGEP. However, independently from a lysosomomotropic drug, severe depletion of ATP and NAD(P)H, e.g., by UV radiation or a potent photosensitizer can trigger likewise the collapse of the lysosomal transmembrane proton gradient resulting in lysosomal C16-ceramide synthesis and pruritic papules. This kind of papules are equally present in polymorphous light eruption (PMLE/PLE) and acne aestivalis (Mallorca acne). The suggested model of a compartmentalized ceramide metabolism provides a more sophisticated explanation of cutaneous drug adverse effects and the individual sensitivity to UV radiation. Parameters such as pKa and ClogP of the triggering drug, cutaneous fatty acid profile, and ceramide profile enables new concepts in risk assessment and scoring of AGEP as well as prophylaxis outcome.

Current Perspectives on Severe Drug Eruption

Adverse drug reactions involving the skin are commonly known as drug eruptions. Severe drug eruption may cause severe cutaneous adverse drug reactions (SCARs), which are considered to be fatal and life-threatening, including Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), acute generalized exanthematous pustulosis (AGEP), and drug reaction with eosinophilia and systemic symptoms (DRESS). Although cases are relatively rare, approximately 2% of hospitalized patients are affected by SCARs. There is an incidence of 2 to 7 cases/million per year of SJS/TEN and 1/1000 to 1/10,000 exposures to offending agents result in DRESS. However, the mortality rate of severe drug eruptions can reach up to 50%. SCARs represent a real medical emergency, and early identification and proper management are critical to survival. The common pathogenesis of severe drug eruptions includes genetic linkage with HLA- and non-HLA-genes, drug-specific T cell-mediated cytotoxicity, T cell receptor restriction, and cytotoxicity mechanisms. A multidisciplinary approach is required for acute management. Immediate withdrawal of potentially causative drugs and specific supportive treatment is of great importance. Immunoglobulins, systemic corticosteroids, and cyclosporine A are the most frequently used treatments for SCARs; additionally, new biologics and plasma exchange are reasonable strategies to reduce mortality. Although there are many treatment methods for severe drug eruption, controversies remain regarding the timing and dosage of drug eruption. Types, dosages, and indications of new biological agents, such as tumor necrosis factor antagonists, mepolizumab, and omalizumab, are still under exploration. This review summarizes the clinical characteristics, risk factors, pathogenesis, and treatment strategies of severe drug eruption to guide clinical management.

Acute and Chronic Management of Ocular Disease in Stevens Johnson Syndrome/Toxic Epidermal Necrolysis in the USA

Stevens Johnson syndrome and toxic epidermal necrolysis are on a spectrum of a severe, immune-mediated, mucocutaneous disease. Ocular involvement occurs in the vast majority of cases and severe involvement can lead to corneal blindness. Treatment in the acute phase is imperative in mitigating the severity of chronic disease. Advances in acute treatment such as amniotic membrane transplantation have shown to significantly reduce the severity of chronic disease. However, AMT is not a panacea and severe chronic ocular disease can and does still occur even with aggressive acute treatment. Management of chronic disease is equally critical as timely intervention can prevent worsening of disease and preserve vision. This mini-review describes the acute and chronic findings in SJS/TEN and discusses medical and surgical management strategies.

Drug Allergy and Cutaneous Adverse Reactions

Allergy or hypersensitivity to drugs often affects the skin and sometimes also mucosa. While immediate type reactions show a rather homogeneous pattern, delayed type reactions reveal a high variability. In both cases it may not always be easy to differentiate drug reactions from non-drug-induced skin conditions. Furthermore, the different types of cutaneous adverse reactions may be difficult to distinguish in the beginning. This accounts predominately for delayed hypersensitivity reactions that can occur after a variety of medications and present with manifold lesions. Most of these cutaneous adverse reactions are mild, but some are severe with high morbidity and mortality. In the clinical setting, it is important to recognize the signs that point to a more severe condition early on in order to initiate appropriate management. In addition, it is crucial to identify the potentially culprit medication on the basis of a detailed medication history and by evaluating the relevant exposure times of certain drugs that differ substantially between the various reaction types. After the acute stage of the adverse reaction is managed successfully, further allergologic testing may be undertaken to confirm the offending drug.

Recognition and Management of Severe Cutaneous Adverse Drug Reactions (Including Drug Reaction with Eosinophilia and Systemic Symptoms, Stevens-Johnson Syndrome, and Toxic Epidermal Necrolysis)

Severe cutaneous adverse reactions to medications (SCARs) include drug reaction with eosinophilia and systemic symptoms, Stevens-Johnson syndrome, toxic epidermal necrolysis, and acute generalized exanthematous pustulosis. They are all non-immunoglobulin E mediated hypersensitivity reaction patterns, distinguished from simple cutaneous drug eruptions by immunologic pathogenesis and internal organ involvement. Herein the clinical features, diagnostic workup, and management considerations are presented for each of these major SCARs.

Severe cutaneous adverse reaction associated with antiseizure medications: Diagnosis, management, and prevention

Severe cutaneous adverse reactions (SCARs) are potentially life-threatening, with considerable morbidity and mortality. They are nonimmediate hypersensitivity reactions that occur in specifically predisposed patients with delayed T-cell-mediated hypersensitivity reaction. Antiseizure medications (ASMs) are among the drugs that can induce SCAR. Increased awareness of SCAR among clinicians treating patients with ASMs is critically important for early recognition of symptoms, prompt identification and removal of the causal drug, and early intervention to reduce SCAR-related acute and long-term morbidity and mortality. The diagnosis, management, and prevention of Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and drug reaction with eosinophilia and systemic symptoms (DRESS) are reviewed, along with the current understanding of the pathomechanisms and role of genetics in SCAR development. Supportive care and immunomodulating treatments for SCAR are discussed.

Clinical, biochemical, and serologic predictors of drug reaction with eosinophilia and systemic symptoms syndrome: A prospective case-control study

BACKGROUND

Detailed scoring systems such as the European Registry of Severe Cutaneous Adverse Reactions (RegiSCAR) score for validating a diagnosis of drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome are available, but there is no rapid, easy tool to identify DRESS at presentation.

OBJECTIVE

To identify the clinical, biochemical, and serologic markers predicting the DRESS syndrome and its severity.

METHODS

In this prospective observational study, 25 patients with the DRESS syndrome and 25 control patients with maculopapular drug rash were recruited. Baseline clinical, biochemical, and serologic markers, such as high-sensitivity C-reactive protein (hsCRP), erythrocyte sedimentation rate, and thymus and activation-regulated chemokine (TARC) levels, were recorded and their utility in identifying the DRESS syndrome at presentation and predicting severity was analyzed.

RESULTS

The effectiveness of TARC level (>613.25 pg/mL), total body surface area (TBSA, >35%), hsCRP (>5 mg/L), eosinophils (>6%), absolute eosinophil count (>450 cells/mm³), and aspartate transaminase (>92 U/L) were statistically similar to the effectiveness of the RegiSCAR DRESS validation score (≥2) in diagnosing the DRESS syndrome. A combination model (TBSA at baseline, eosinophil count, and hsCRP) at the cutoff of 6.8 had a sensitivity of 96% and a specificity of 100%. Baseline serum TARC levels did not predict the DRESS severity or outcome.

LIMITATIONS

Small sample size.

CONCLUSION

The combination of TBSA involvement, eosinophil count, and hsCRP levels can predict the DRESS syndrome at presentation.

[Ocular involvement in Stevens-Johnson syndrome and toxic epidermal necrolysis]

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are rare severe and often life-threatening reactions of the skin and mucous membranes. They are considered as a single disease entity with different expressions of severity and are summarized under the term epidermal necrolysis (EN). There is a high risk of ocular involvement, which can lead to long-lasting eye problems and even blindness without immediate ophthalmological treatment. The acute occurrence, the unpredictable course and extreme variation in the manifestation of complications require an interdisciplinary approach. A rapid diagnosis of eye involvement and initiation of an intensive lubricating and anti-inflammatory surface treatment is of utmost importance for the long-term outcome. This article should help ophthalmologists to have a better understanding of this condition and therefore lead to substantial improvement in visual outcome and the quality of life of patients.

Ventilatory support in Stevens-Johnson syndrome and toxic epidermal necrolysis: a systematic review and meta-analysis

Introduction: Stevens-Johnson syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) are blistering cutaneous disorders that often manifest with epidermal and mucosal necrosis. In extreme cases, the upper or bronchial airways are threatened, necessitating intubation and mechanical ventilation. This systematic review and meta-analysis examines the prevalence of mechanical ventilation (MV) in patients with SJS or TENS, despite maximal medical therapy, and additionally aims to identify the risk factors associated with this requirement.Materials and methods: A systematic review of the literature was performed using the PRISMA guidelines and meta-analysis of proportions.Results: Six articles were included, with pooled total of 18648 cases. The weighted prevalence of MV was 27.5% (95%CI 17.8-39.9%). The need for MV was more closely associated with TEN, compared to SJS (OR 4.40, 95%CI 2.73-7.10, I²=48%, p<.00001.) Risk factors associated with the need for MV included bacteremia (OR 5.02, 95%CI 2.87-8.79, I²=0%, p<.00001), shock/organ failure on admission (OR 261.99, 95%CI 21.88-3137, I²=71, p<.0001), total body surface area (TBSA) >30% (OR 4.47, 95%CI 1.41-14.20, I²=71, p=.01.)Conclusion: Limited published evidence with significant heterogeneity exists within the literature regarding the need for MV in SJS and TEN. Greater cutaneous involvement, and more critically unwell patients appear more likely to require MV.

Drug hypersensitivity reactions in Asia: regional issues and challenges

There are geographical, regional, and ethnic differences in the phenotypes and endotypes of patients with drug hypersensitivity reactions (DHRs) in different parts of the world. In Asia, aspects of drug hypersensitivity of regional importance include IgE-mediated allergies and T-cell-mediated reactions, including severe cutaneous adverse reactions (SCARs), to beta-lactam antibiotics, antituberculous drugs, nonsteroidal anti-inflammatory drugs (NSAIDs) and radiocontrast agents. Delabeling of low-risk penicillin allergy using direct oral provocation tests without skin tests have been found to be useful where the drug plausibility of the index reaction is low. Genetic risk associations of relevance to Asia include human leucocyte antigen (HLA)-B*1502 with carbamazepine SCAR, and HLA-B*5801 with allopurinol SCAR in some Asian ethnic groups. There remains a lack of safe and accurate diagnostic tests for antituberculous drug allergy, other than relatively high-risk desensitization regimes to first-line antituberculous therapy. NSAID hypersensitivity is common among both adults and children in Asia, with regional differences in phenotype especially among adults. Low dose aspirin desensitization is an important therapeutic modality in individuals with cross-reactive NSAID hypersensitivity and coronary artery disease following percutaneous coronary intervention. Skin testing allows patients with radiocontrast media hypersensitivity to confirm the suspected agent and test for alternatives, especially when contrasted scans are needed for future monitoring of disease relapse or progression, especially cancers.