Low N-acetylating capacity in patients with Stevens-Johnson syndrome and toxic epidermal necrolysis

Systemic interventions for treatment of Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and SJS/TEN overlap syndrome

BACKGROUND

Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and SJS/TEN overlap syndrome are rare, severe cutaneous adverse reactions usually triggered by medications. In addition to tertiary-level supportive care, various systemic therapies have been used including glucocorticoids, intravenous immunoglobulins (IVIGs), cyclosporin, N-acetylcysteine, thalidomide, infliximab, etanercept, and plasmapheresis. There is an unmet need to understand the efficacy of these interventions.

OBJECTIVES

To assess the effects of systemic therapies (medicines delivered orally, intramuscularly, or intravenously) for the treatment of SJS, TEN, and SJS/TEN overlap syndrome.

SEARCH METHODS

We searched the following databases up to March 2021: the Cochrane Skin Specialised Register, CENTRAL, MEDLINE, and Embase. We also searched five clinical trial registers, the reference lists of all included studies and of key review articles, and a number of drug manufacturer websites. We searched for errata or retractions of included studies.

SELECTION CRITERIA

We included only randomised controlled trials (RCTs) and prospective observational comparative studies of participants of any age with a clinical diagnosis of SJS, TEN, or SJS/TEN overlap syndrome. We included all systemic therapies studied to date and permitted comparisons between each therapy, as well as between therapy and placebo.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures as specified by Cochrane. Our primary outcomes were SJS/TEN-specific mortality and adverse effects leading to discontinuation of SJS/TEN therapy. Secondary outcomes included time to complete re-epithelialisation, intensive care unit length of stay, total hospital length of stay, illness sequelae, and other adverse effects attributed to systemic therapy. We rated the certainty of the evidence for each outcome using GRADE.

MAIN RESULTS

We included nine studies with a total of 308 participants (131 males and 155 females) from seven countries. We included two studies in the quantitative meta-analysis. We included three RCTs and six prospective, controlled observational studies. Sample sizes ranged from 10 to 91. Most studies did not report study duration or time to follow-up. Two studies reported a mean SCORe of Toxic Epidermal Necrosis (SCORTEN) of 3 and 1.9. Seven studies did not report SCORTEN, although four of these studies reported average or ranges of body surface area (BSA) (means ranging from 44% to 51%). Two studies were set in burns units, two in dermatology wards, one in an intensive care unit, one in a paediatric ward, and three in unspecified inpatient units. Seven studies reported a mean age, which ranged from 29 to 56 years. Two studies included paediatric participants (23 children). We assessed the results from one of three RCTs as low risk of bias in all domains, one as high, and one as some concerns. We judged the results from all six prospective observational comparative studies to be at a high risk of bias. We downgraded the certainty of the evidence because of serious risk of bias concerns and for imprecision due to small numbers of participants. The interventions assessed included systemic corticosteroids, tumour necrosis factor-alpha (TNF-alpha) inhibitors, cyclosporin, thalidomide, N-acetylcysteine, IVIG, and supportive care. No data were available for the main comparisons of interest as specified in the review protocol: etanercept versus cyclosporin, etanercept versus IVIG, IVIG versus supportive care, IVIG versus cyclosporin, and cyclosporin versus corticosteroids. Corticosteroids versus no corticosteroids It is uncertain if there is any difference between corticosteroids (methylprednisolone 4 mg/kg/day for two more days after fever had subsided and no new lesions had developed) and no corticosteroids on disease-specific mortality (risk ratio (RR) 2.55, 95% confidence interval (CI) 0.72 to 9.03; 2 studies; 56 participants; very low-certainty evidence). Time to complete re-epithelialisation, length of hospital stay, and adverse effects leading to discontinuation of therapy were not reported. IVIG versus no IVIG It is uncertain if there is any difference between IVIG (0.2 to 0.5 g/kg cumulative dose over three days) and no IVIG in risk of disease-specific mortality (RR 0.33, 95% CI 0.04 to 2.91); time to complete re-epithelialisation (mean difference (MD) -2.93 days, 95% CI -4.4 to -1.46); or length of hospital stay (MD -2.00 days, 95% CI -5.81 to 1.81). All results in this comparison were based on one study with 36 participants, and very low-certainty evidence. Adverse effects leading to discontinuation of therapy were not reported. Etanercept (TNF-alpha inhibitor) versus corticosteroids Etanercept (25 mg (50 mg if weight > 65 kg) twice weekly "until skin lesions healed") may reduce disease-specific mortality compared to corticosteroids (intravenous prednisolone 1 to 1.5 mg/kg/day "until skin lesions healed") (RR 0.51, 95% CI 0.16 to 1.63; 1 study; 91 participants; low-certainty evidence); however, the CIs were consistent with possible benefit and possible harm. Serious adverse events, such as sepsis and respiratory failure, were reported in 5 of 48 participants with etanercept and 9 of 43 participants with corticosteroids, but it was not clear if they led to discontinuation of therapy. Time to complete re-epithelialisation and length of hospital stay were not reported. Cyclosporin versus IVIG  It is uncertain if there is any difference between cyclosporin (3 mg/kg/day or intravenous 1 mg/kg/day until complete re-epithelialisation, then tapered off (10 mg/day reduction every 48 hours)) and IVIG (continuous infusion 0.75 g/kg/day for 4 days (total dose 3 g/kg) in participants with normal renal function) in risk of disease-specific mortality (RR 0.13, 95% CI 0.02 to 0.98, 1 study; 22 participants; very low-certainty evidence). Time to complete re-epithelialisation, length of hospital stay, and adverse effects leading to discontinuation of therapy were not reported. No studies measured intensive care unit length of stay.

AUTHORS' CONCLUSIONS

When compared to corticosteroids, etanercept may result in mortality reduction. For the following comparisons, the certainty of the evidence for disease-specific mortality is very low: corticosteroids versus no corticosteroids,  IVIG versus no IVIG and cyclosporin versus IVIG. There is a need for more multicentric studies, focused on the most important clinical comparisons, to provide reliable answers about the best treatments for SJS/TEN.

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?

Whole-Exome Sequencing in Patients Affected by Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis Reveals New Variants Potentially Contributing to the Phenotype

Background

Adverse drug reactions (ADRs) are frequent occurring events that can essentially be defined as harmful or unpleasant symptoms secondary to the use of a medicinal product. ADRs involve a wide spectrum of clinical manifestations ranging from minor itching and rash to life-threatening reactions. Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are rare ADRs. SJS-TEN may be considered a polygenic pathology due to additive/epistatic effects caused by sequence variants in numerous genes. Next-generation sequencing (NGS) represents a potentially interesting exploration tool in such scenario as it facilitates the simultaneous analysis of large genomic regions and genes at affordable cost.

Methods

The present study has involved using whole-exome sequencing (WES) for the first time on SJS-TEN patients. It involved robust and innovative multistep bioinformatics analysis focusing on 313 candidate genes potentially participating in the disease’s aetiology, specific drugs’ metabolism and gene regulation.

Results

We identified combinations of frequently occurring and rare variants that may contribute to the disease’s pathogenesis. Depending on the specific drug being taken, different variants (and alleles) in NAT2, CYP2D8, CYP2B6, ABCC2, UGT2B7 and TCF3 were identified as coherent candidates representing potential future markers for SJS-TEN.

Conclusion

The present study proposed and has described (for the first time) a large-scale genomic analysis of patients affected by SJS-TEN. The genes and variants identified represent relevant candidates potentially participating in the disease’s pathogenesis. Corroborating that proposed by others, we found that complex combinations of frequently occurring and rare variants participating in particular drug metabolism molecular cascades could be associated with the phenotype. TCF3 TF may be considered a coherent candidate for SJS-TEN that should be analysed in new cohorts of patients having ADRs.

Outcomes of Stevens-Johnson syndrome and toxic epidermal necrolysis in HIV-infected patients when using systemic steroids and/or intravenous immunoglobulins in Pietermaritzburg, South Africa

Background

Stevens–Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are severe life-threatening mucocutaneous reactions. There is an ongoing controversy regarding the use of systemic corticosteroids and intravenous immunoglobulin (IVIG) in SJS/TEN and their utility in HIV-infected patients.

Objectives

The objective was to assess the outcome of a combination of intensive supportive care with oral corticosteroids in SJS and a combination of systemic steroids and IVIG for 3 consecutive days in HIV-infected patients with TEN. In addition, we assessed management in a general dermatology ward without implementing wound debridement.

Methods

This was a retrospective cohort study of 36 HIV-infected adults with SJS/TEN admitted to a tertiary dermatology unit between 1st January 2010 and 31st July 2011. Standard-of-care protocols included identification and elimination of the possible causative drug, meticulous wound care without debridement, initiation of oral prednisone (1 mg/kg/day) on admission for 3 consecutive days, and the addition of IVIG (1 g/kg/day) for 3 consecutive days to those with TEN.

Results

Of the 36 patients in the study, 32 were female. Nevirapine was the commonest drug implicated. A diagnosis of tuberculosis did not increase the case fatality rate. Complications included infections, anaemia, drug-induced hepatitis, ocular involvement, renal impairment, deep vein thrombosis, respiratory distress, Leucopenia, gastritis and hypernatremia. The overall survival rate was 97%.

Conclusion

HIV-infected SJS and TEN patients were treated in a tertiary dermatology ward with a treatment plan of skin care, and a combination of systemic corticosteroids and IVIG respectively had a survival rate of 97%.

Mycoplasma Pneumoniae Associated with Stevens Johnson Syndrome

We describe a case of Mycoplasma pneumoniae chest infection associated with Stevens Johnson syndrome. The patient had extensive epidermal bullous vesicles, oropharyngeal and genital ulceration and required prolonged ventilation due to respiratory failure. Mycoplasma pneumoniae infections are often asymptomatic but can involve multiple organ systems. Respiratory tract involvement is generally benign though 3 to 10% of patients develop clinical pneumonia. Secondary skin reactions are common (20 to 25%), although few patients infected develop Stevens Johnson syndrome. It has been suggested that Mycoplasma pneumoniae may be the most common infectious cause of Stevens Johnson syndrome.

Adverse Drug Reactions

Adverse events and adverse drug reactions are common in clinical practice. Side effects range from the common to the rare and may be confused with other mucocutaneous manifestations resulting from several medications to treat infections, other medical conditions, and in the clinical setting of oncologic treatment. The objective of this chapter to review current data on adverse drug reactions, here classified as (i) severe adverse drug reactions, (ii) uncomplicated cutaneous adverse drug reactions, and (iii) adverse drug reactions caused by chemotherapy drugs, particularly those cases whereby the dermatologist is requested to issue a report and asked to comment on the safety and viability of readministration of a specific drug. We describe aspects associated with these events, presenting a detailed analysis of each of them.

Toxicological effects of trichloroethylene exposure on immune disorders

Trichloroethylene (TCE) is one of the most common ground water contaminants in USA. Even though recent regulation mandates restricted utilization of TCE, its use is not completely prohibited, especially in industrial and manufacturing processes. The risk of TCE on human health is an ongoing field of study and its implications on certain diseases such as cancer has been recognized and well-documented. However, the link between TCE and immune disorders is still an under-studied area. Studies on the risk of TCE on the immune system is usually focused on certain immune class disorders, but consensus on the impact of TCE on the immune system has not been established. This review presents representative work that investigates the effect of TCE on immune disorders and highlights future opportunities. We attempt to provide a broader perspective of the risks of TCE on the immune system and human health.

Stevens-Johnson Syndrome Patient Received Combination Chemotherapy Gemcitabine, Cisplatin, and 5-FU for Biliary Tract Cancer

Stevens-Johnson syndrome has been an acute, usually self-limiting disease of the skin and mucous membranes. This case report has presented an evidence of the development Stevens - Johnson syndrome associated with combination chemotherapy administration of 5FU, gemcitabin and cisplatin in a patient with biliary tract cancer. Our case was a 54-year-old woman patient, a case of biliary tract cancer who has developed more severe symptoms of Stevens-Johnson syndrome. Diagnosis has confirmed by skin biopsy of an affected area .The patient has improved with supportive care, and during 25 day occurred recovery. Although Stevens-Johnson syndrome has been a rare toxicity, physicians should pay a special attention to the monitoring of biliary tract cancer patients on combination chemotherapy with 5FU, cisplatin and gemcitabin.

Toxic epidermal necrolysis

Toxic epidermal necrolysis (TEN) is a rare, life-threatening drug-induced skin disease with a mortality rate of approximately 30%. The clinical hallmark of TEN is a marked skin detachment caused by extensive keratinocyte cell death associated with mucosal involvement. The exact pathogenic mechanism of TEN is still uncertain. Recent advances in this field have led to the identification of several factors that might contribute to the induction of excessive apoptosis of keratinocytes. In addition, specific human leukocyte antigen types seem to be associated with certain drugs and the development of TEN. As well-controlled studies are lacking, patients are treated with various immunomodulators (e.g. intravenous immunoglobulin) in addition to the best supportive care.

Correlation between drug–drug interaction-induced Stevens–Johnson syndrome and related deaths in Taiwan

Concomitant use of some drugs can lead to interactions between them resulting in severe adverse effects. To date, there are few reports of incidences of Stevens-Johnson syndrome (SJS) associated with combination drug administration. Therefore, we studied the relationship between drug combinations and SJS-related mortality, with the hope that a retrospective study of this nature would provide information crucial for the prevention of future drug-drug interaction related deaths attributable to SJS. This retrospective longitudinal study used mortality cases from 1999 to 2008 that were diagnosed as erythema multiforme (International Classification of Diseases, Ninth Revision, Clinical Modification 695.1) from the National Health Insurance database in Taiwan. Statistical comparisons of the results were performed using analysis of variance (ANOVA), independent sample t-tests, and odds ratio (OR). In this way, the relationship between combinations of SJS-inducing drugs and mortality could be determined. A total of 111 patients who had died, including 63 males and 48 females (66.0 ± 20 and 70.0 ± 17.7 years, respectively), were suspected of having experienced drug-drug interaction-related adverse effects. The associated drug combinations included allopurinol and ampicillin (p = 0.049), carbamazepine and sulfamethoxazole/trimethoprim (TMP) (p < 0.0001), carbamazepine and phenytoin (p < 0.0001), sulfamethoxazole/TMP and phenytoin (p = 0.015), sulfadoxine and piroxicam (p = 0.045), phenobarbital and cephalexin (p < 0.0001), ampicillin and erythromycin (p < 0.0001), erythromycin and minocycline (p < 0.0001), and vancomycin and ethambutol (p < 0.0001) administered 1 month before the patients’ deaths. Caution should be exercised when administering any drugs that may possibly induce SJS. In addition, attention should be paid to ensure prompt identification of possible drug-drug interactions, and patients should be closely monitored. Furthermore, medications should be immediately discontinued at the first sign or symptom suggesting the occurrence of drug-related SJS, and then prompt, adequate supportive care should be provided.

Adverse cutaneous drug eruptions: current understanding

Adverse cutaneous drug reactions are recognized as being major health problems worldwide causing considerable costs for health care systems. Most adverse cutaneous drug reactions follow a benign course; however, up to 2% of all adverse cutaneous drug eruptions are severe and life-threatening. These include acute generalized exanthematous pustulosis (AGEP), drug reaction with eosinophilia and systemic symptoms (DRESS), Stevens-Johnson syndrome (SJS), and toxic epidermal necrolysis (TEN). Physicians should be aware of specific red flags to rapidly identify these severe cutaneous drug eruptions and initiate appropriate treatment. Besides significant progress in clinical classification and treatment, recent studies have greatly enhanced our understanding in the pathophysiology of adverse cutaneous drug reactions. Genetic susceptibilities to certain drugs have been identified in SJS/TEN patients, viral reactivation in DRESS has been elucidated, and the discovery of tissue resident memory T cells helps to better understand the recurrent site-specific inflammation in patients with fixed drug eruption.

Ocular mucous membrane pemphigoid after Lyell syndrome: occasional finding or predisposing event?

PURPOSE

Ocular mucous membrane pemphigoid (OMMP) is an autoimmune disease involving the eye and characterized by subepithelial detachment resulting from an immunologic reaction against conjunctival basal membrane zone (BMZ) antigens. Lyell syndrome (LS) is a drug-induced, T cell-mediated, cytotoxic reaction involving the mucocutaneous areas. Two patients with LS are presented in whom OMMP developed.

DESIGN

Report of 2 cases.

PARTICIPANTS

Two male patients, 80 and 60 years old, with persistent corneal ulcerations, corneal melting, and inflammation some months after an LS episode.

METHODS

Conjunctival biopsy samples were obtained to perform direct immunofluorescence (DIF) and histologic analyses. Indirect immunofluorescence (IIF) and enzyme-linked immunosorbent assay (ELISA) also were performed.

MAIN OUTCOME MEASURES

Immunodeposit findings on the conjunctival BMZ obtained by DIF and IIF, inflammatory infiltration of the corneoconjunctival samples studied by histologic analysis, and autoantibodies of patient sera directed against BMZ antigens tested by ELISA.

RESULTS

Direct immunofluorescence analyses showed immunoglobulin G and complement 3 component deposits along the BMZ in a linear pattern. Histologic analysis revealed the presence of eosinophils, neutrophils, and mast cells with fibrin deposition in the substantia propria of both patients; the data confirmed the clinical suspicion of OMMP. The IIF and ELISA results were negative.

CONCLUSIONS

Chronic eye surface injury associated with LS may promote autoimmunization against ocular epithelial BMZ antigens, playing a strategic role in the subsequent onset of OMMP. The occurrence of OMMP after LS could be an occasional finding, or conversely, LS could be an underestimated predisposing factor in the development of OMMP.

New insights in toxic epidermal necrolysis (Lyell's syndrome): clinical considerations, pathobiology and targeted treatments revisited

Drug-induced toxic epidermal necrolysis (TEN), also known as Lyell's syndrome, is a life-threatening drug reaction characterized by extensive destruction of the epidermis and mucosal epithelia. The eyes are typically involved in TEN. At present, the disease has a high mortality rate. Conceptually, TEN and the Stevens-Johnson syndrome are closely related, although their severity and outcome are different. Distinguishing TEN from severe forms of erythema multiforme relies on consideration of aetiological, clinical and histological characteristics. The current understanding of the pathomechanism of TEN suggests that keratinocytes are key initiator cells. It is probable that the combined deleterious effects on keratinocytes of both the cytokine tumour necrosis factor (TNF)-alpha and oxidative stress induce a combination of apoptotic and necrotic events. As yet, there is no evidence indicating the superiority of monotherapy with corticosteroids, ciclosporin (cyclosporine) or intravenous immunoglobulins over supportive care only for patients with TEN. However, the current theory of TEN pathogenesis supports the administration of a combination of antiapoptotic/antinecrotic drugs (e.g. anti-TNF-alpha antibodies plus N-acetylcysteine) targeting different levels of the keratinocyte failure machinery.

Effects of genetic polymorphisms of N-Acetyltransferase on trichloroethylene-induced hypersensitivity dermatitis among exposed workers

The hypersensitivity dermatitis induced by trichloroethylene (TCE) exposure was influenced by individual genetic susceptibility factors. In this paper, a case-control study was conducted to investigate effects of various genotypes and phenotypes of N-Acetyltransferases (NATs) on individual susceptibility to the disease. The study consists of 111 patients with hypersensitivity dermatitis and 154 healthy TCE-exposed workers. Polymerase chain reaction-restriction fragment length polymorphism was used to detect the polymorphic sites of NAT1 at nt 1095 and 1088 and the sites of NAT2 at nt 481, 590, and 857. Logistic regression was used to calculate the odds ratios (ORs) and 95% confidence intervals (95%CI). The results reveal that subjects with intermediate or slow acetylators of NAT2 have a 2.01 fold (95%CI=1.14-3.54) higher risk for the disease than subjects with the fast acetylators. When non-fast NAT2 phenotype (intermediate and slow acetylators) and a slow NAT1 phenotype were combined, the risk for the disease was significantly increased (OR=2.71, 95%CI 1.29-5.70) to the level higher than that observed for NAT2 non-fast acetylators phenotype alone. These findings suggest that slow metabolic phenotype of NAT2 maybe one of risk factor for TCE-induced hypersensitivity dermatitis and combined slow acetylator phenotypes of NAT1 and NAT2 further increase such risk.

Toxic epidermal necrolysis (TEN) Lyell's syndrome

Toxic epidermal necrolysis, a unique rapidly developing mucocutaneous reaction pattern, characterized by sheets of erythema, necrosis and bullous detachment of the epidermis, closely resembling that of scalding of the skin and rapidly fatal, was described by Lyell, and is now recognized as toxic epidermal necrolysis (TEN) Lyell's syndrome. The condition is indistinguishable from staphylococcal scalded skin syndrome (SSSS), and generalized fixed drug eruption. Hence, there has always been controversy as regards terminology. It is well conceived that TEN is equivalent to Stevens-Johnson syndrome (SJS), at its greatest severity. TEN, therefore, is a great challenge and warrants instant attention based on a thorough knowledgeable background covering several related facets including the recent advances in pathogenesis and management strategies. The details contained in the following text should prove very useful in the comprehension of a largely intractable entity.

The ophthalmologic management of acute Stevens-Johnson syndrome

Stevens-Johnson syndrome (SJS) and its more severe variant, toxic epidermal necrolysis (TEN), cause significant ocular surface damage. The majority of affected patients develop conjunctival inflammation during the acute phase of the disease. If intense, this inflammation yields permanent destruction of the normal mucosal tissue of the ocular surface and eyelids. Loss of the normal glandular structures leads to severe dry eye problems and vision loss. Medical treatments do little to arrest these problems, and repairing the damage after the acute phase is difficult, if not impossible. Recently, the application of cryopreserved amniotic membrane to the ocular surface during the acute phase of the disease has shown great promise in limiting the destructive inflammation and its long-term sequelae. A rationale for this treatment and a detailed description of the application procedure are provided, along with practical guidelines for the managing surgeon.

Stevens-Johnson syndrome in a child with chronic mercury exposure and 2,3-dimercaptopropane-1-sulfonate (DMPS) therapy

INTRODUCTION

Stevens-Johnson syndrome (SJS) is an uncommon and potentially serious mucocutaneous disease. The most important step in the management of SJS is early recognition and immediate withdrawal of the causative agent. We present a patient with SJS associated with dimercaptopropane-1-sulfonate (DMPS) therapy.

CASE REPORT

An asymptomatic 11-year old boy who had been exposed chronically to mercury vapour had a 24-hour urine mercury concentration of 37 microgram/L (reference value <10 microgram/L). Exposure to the mercury vapour was stopped and treatment with oral DMPS was begun. After two weeks of therapy, he developed a disseminated cutaneous eruption of red pruritic macules on his chest and back, which three days later had spread all over his body with the discrete maculae becoming confluent; erosions and crusts developed on his lips and he had blisters in his mouth. The diagnosis of SJS was made, the DMPS was stopped, and the SJS resolved gradually.

DISCUSSION

Chelation agents like DMPS or DMSA are increasingly used and are available over the counter in some countries. These drugs are used in patients with complaints that are attributed to mercury-containing dental amalgams and in children with autism.

CONCLUSION

The reported association suggests that SJS may be a potential complication of DMPS therapy, and this should be considered in the risk-benefit analysis of chelation. The reported association suggests that SJS may be a potential complication of DMPS therapy, and this should be considered in the risk-benefit analysis of chelation.

TOXIC EPIDERMAL NECROLYSIS/STEVENS?JOHNSON SYNDROME: CURRENT TRENDS IN MANAGEMENT

BACKGROUND

Toxic epidermal necrolysis (TEN) is an uncommon but potentially life-threatening condition that involves sloughing of the skin at the dermoepidermal junction. TEN is a well-recognized syndrome and is part of a range of severe mucocutaneous intolerance reactions, mostly elicited by drugs and/or their metabolites. Reported mortality rates vary widely from 20 to 75%. Several systemic treatment protocols for TEN have been published; however, none has been formally standardized in a randomized controlled trial. The present study documents the current management principles and trends seen in 16 patients admitted with TEN or Stevens-Johnson syndrome over a 5-year period at the Concord Repatriation General Hospital Burns Unit.

METHOD

Data were collected by retrospective chart review, and parameters included in the study were patient demographics, causative agents, percentage total body surface area and/or mucosal involvement, complications, treatment and outcome. In particular, dressing choice and documented healing of skin lesions were noted.

RESULTS

Sixteen patients were identified, with the beta-lactam antibiotics most commonly implicated as the cause. Complications tended to relate to degree of sepsis and/or mucous membrane involvement. Nanocrsytalline silver dressings, such as Acticoat (Smith & Nephew, Mount Waverley, Victoria, Australia), were used predominantly in more recent cases.

CONCLUSION

The shift in dressing choice from traditional Vaseline-impregnated gauze coincided with a general trend towards the use of nanocrystalline silver dressings for superficial burns after 2003. The nanocrystalline silver dressings have shown considerable advantage over previously used dressings, with no adverse reactions noted and good healing of the skin lesions for all patients.

Toxic epidermal necrolysis

Toxic epidermal necrolysis (TEN) is an unpredictable, life-threatening drug reaction associated with a 30% mortality. Massive keratinocyte apoptosis is the hallmark of TEN. Cytotoxic T lymphocytes appear to be the main effector cells and there is experimental evidence for involvement of both the Fas-Fas ligand and perforin/granzyme pathways. Optimal treatment for these patients remains to be clarified. Discontinuation of the offending drug and prompt referral to a burn unit are generally agreed upon steps. Beyond that, however, considerable controversy exists. Evidence both pro and con exists for the use of IVIG, systemic corticosteroid, and other measures. There is also evidence suggesting that combination therapies may be of value. All the clinical data, however, is anecdotal or based on observational or retrospective studies. Definitive answers are not yet available. Given the rarity of TEN and the large number of patients required for a study to be statistically meaningful, placebo controlled trials are logistically difficult to accomplish. The absence of an animal model further hampers research into this condition. This article reviews recent data concerning clinical presentation, pathogenesis and treatment of TEN.

LEARNING OBJECTIVES

At the conclusion of this learning activity, participants should have acquired a more comprehensive knowledge of our current understanding of the classification, clinical presentation, etiology, pathophysiology, prognosis, and treatment of TEN.

Síndrome de Stevens-Johnson y necrólisis epidérmica tóxica: experiencia clínica y revisión de la literatura especializada

INTRODUCTION

The aim of this work is to reflect the clinical experience of the Dermatology Department of Hospital General in Valencia with Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) or Lyell's syndrome over the last 15 years.

METHODS

Data on epidemiology, likely causal agents, complementary tests, concomitant pathologies, management, evolution and complications was gathered through a retrospective study.

RESULTS

Thirteen patients were included, with a mean age of 53 years. The most frequently involved drugs were antibiotics (50 %), followed by anti-convulsants (16.6 %). The mucous membranes were involved in 84.6 % of the cases. 61.5 % of the patients presented with systemic symptoms. The most frequent laboratory finding was hypoproteinemia. Corticosteroids were used in 69 % of the cases, and intravenous immunoglobulins in 15 %. Two oncological patients with a diagnosis of TEN died (15 % overall mortality).

CONCLUSIONS

SJS and TEN are infrequent mucocutaneous reactions, often drug induced, with significant associated morbidity and mortality. Their pathogenesis is still partially unknown, and no specific treatment has been proven to be clearly beneficial; therefore, the best treatment consists of early diagnosis, the withdrawal of the suspect drug and support therapy.

Toxic epidermal necrolysis and Stevens Johnson syndrome: our current understanding

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN, Lyell's syndrome) are now considered to be distinct clinical entities within a spectrum of adverse cutaneous drug reactions of increasing severity based on their surface of skin detachment. Within this spectrum, SJS which can be considered as a minor form of TEN is characterized by less than 10% body surface area of skin detachment, and an average reported mortality of 1-5%, whereas TEN is characterized by more than 30% skin detachment, and an average reported mortality 25-35%. Both SJS and TEN are characterized morphologically by the rapid onset of keratinocyte cell death by apoptosis, a process that results in the separation of the epidermis from the dermis. Recent evidence is supportive of a role for inflammatory cytokines and the death receptor Fas and its ligand FasL in the pathogenesis of keratinocyte apoptosis during TEN. This Fas-mediated keratinocyte apoptosis that is the last step culminating in epidermal detachment in TEN can be inhibited in vitro by antagonistic monoclonal antibodies to Fas, and by intravenous immunoglobulins (IVIG) which have been shown to contain natural anti-Fas antibodies. Consequently, over the last few years, numerous case reports and 9 non-controlled clinical studies containing 10 or more patients have analyzed the therapeutic effect of IVIG in TEN. Taken together, although each study has its potential biases, 7 of 9 such studies point towards a benefit of IVIG used at doses greater than 2 g/kg on the mortality associated with TEN. These studies should serve as the basis for designing an appropriate prospective trial or for conducting a metaanalysis in the near future, in order to determine the therapeutic efficacy of IVIG in TEN.

Novel Treatments for Drug-Induced Toxic Epidermal Necrolysis (Lyell’s Syndrome)

Drug-induced toxic epidermal necrolysis (TEN) is a life-threatening disease characterized by extensive destruction of the epidermis. It apparently results from the formation of specific toxic drug metabolites by the keratinocytes. The mortality rate which averages 25-30% is mainly due to secondary septicemia, and to ionic and metabolic disturbances following loss of epidermal integrity. Apoptosis is the likely mechanism leading to massive keratinocyte death in TEN. Dysregulations in the tumor necrosis factor-alpha (TNF-alpha) pathway, CD95 system (Fas ligand, CD95L; Fas receptor, CD95R) and calcium homeostasis in the epidermis are involved in this apoptotic process. An active role has also been ascribed to T lymphocytes, macrophages and factor XIIIa-positive dermal dendrocytes. Despite progress, treatment of TEN remains controversial. In the past, systemic glucocorticoids were used in order to target the inflammatory reaction in TEN. However, there was no evidence for improvement of the healing process, while corticosteroids worsened the prognosis by increasing the risk of septicemia. Only a few cases have been treated with other drugs including cyclophosphamide, pentoxyfilline, thalidomide, anti-TNF-alpha antibodies and cyclosporin A. In the recent past, some TEN patients were treated with intravenous human immunoglobulins (IVIG). The rationale for such a treatment was to block the CD95 system on keratinocytes. The early promising clinical results of IVIG treatment in TEN were subsequently challenged. This review compares the effectiveness and drawbacks of the major drugs presently used in TEN treatment. Some future prospects in TEN management are also discussed.

[Emergencies in allergology]

The clinical presentation of allergological emergencies is heterogeneous. The most important conditions are anaphylaxis (which is frequent) and Stevens-Johnson syndrome or toxic epidermal necrolysis (which are rare). In the acute phase it is most important to recognize the exogenous elicitation of the condition as soon as possible, otherwise severe sequelae, even death of the patient, may occur. Management is based on immediate elimination of possible causative agents and symptomatic therapeutic measures. Furthermore, allergological diagnostics are necessary without delay to identify what has elicited the reaction. This information makes possible long-term treatment in order to avoid further hypersensitivity reactions.

Reações cutâneas graves adversas a drogas - aspectos relevantes ao diagnóstico e ao tratamento - Parte I - Anafilaxia e reações anafilactóides, eritrodermias e o espectro clínico da síndrome de Stevens-Johnson & necrólise epidérmica tóxica (Doença de Lyell)

As reações cutâneas graves adversas a droga (RCGAD) são as que geralmente necessitam de internação hospitalar, por vezes em unidade de terapia intensiva ou de queimados, com observação minuciosa dos sinais vitais e da função de órgãos internos. O objetivo é descrever essas reações, facilitando seu reconhecimento e tratamento. Fazem parte desse grupo a anafilaxia, a síndrome de Stevens-Johnson (SSJ), a necrólise epidérmica tóxica (NET) e, dependendo do envolvimento sistêmico, as eritrodermias. Neste artigo, são abordados as características clínicas e o tratamento de algumas reações adversas a droga: anafilaxia, as eritrodermias, a síndrome de Stevens-Johnson (SSJ) e a necrólise epidérmica tóxica (NET).

Generalized Skin Reactions in Relation to Trichloroethylene Exposure: A Review from the Viewpoint of Drug‐Metabolizing Enzymes

The literature was reviewed to study cases of intoxication with systemic dermatitis associated with exposure to trichloroethylene. The average age of patients in the reports reviewed to date was twenty-nine; these diseases were found in relatively young persons and no difference was found according to gender. Many cases occurred within one month after the onset of exposure to trichloroethylene, and were accompanied by hepatitis, jaundice, hepatomegaly or hepatosplenomegaly. Most of the patients had no history of drug abuse or herpes infection. The level of exposure to trichloroethylene was not recorded in many cases, but ranged from less than 9 ppm to 800 ppm. In the severest cases, the lesions involved mucous membranes such as the conjunctiva and oral cavity, and the patients were diagnosed with Stevens-Johnson syndrome, but the etiology of the disease after trichloroethylene exposure remains unclear. Since several drugs have also been shown to cause systemic dermatitis with hepatitis, susceptibility factors are discussed. Many patients were found to have the slow acetylator genotype of N-acetyltransferase (NAT) 2, suggesting that the NAT2 genotype is a susceptibility factor. This hypothesis may also be applicable to trichloroethylene because NAT is involved in the glutathione-mediated metabolism.

Arylamine N-acetyltransferases and drug response

Arylamine N-acetyltransferases (NATs) play an important role in the interaction of competing metabolic pathways determining the fate of and response to xenobiotics as therapeutic drugs, occupational chemicals and carcinogenic substances. Individual susceptibility for drug response and possible adverse drug reactions are modulated by the genetic predisposition (manifested for example, by polymorphisms) and the phenotype of these enzymes. For all drugs metabolized by NATs, the impact of different in vivo enzyme activities is reviewed with regard to therapeutic use, prevention of side effects and possible indications for risk assessment by phenotyping and/or genotyping. As genes of NATs are susceptibility genes for multifactorial adverse effects and xenobiotic-related diseases, risk prediction can only be made possible by taking the complexity of events into consideration.

Prospective evaluation of detoxification pathways as markers of cutaneous adverse reactions to sulphonamides in AIDS

The use of sulphonamides is complicated by a high rate of cutaneous reactions in AIDS. Metabolic risk factors have been suspected for these reactions. We conducted a prospective study to evaluate whether glutathione S-transferase M1 null genotype, glutathione deficiency and acetylator status as risk factors. To explain the high frequency of slow acetylator phenotype in AIDS patients, we compared N-acetyltransferase-2 phenotype and genotype in this population. AIDS patients treated with sulphonamides for Pneumocystis carinii pneumonia or toxoplasmosis were followed up for cutaneous reactions. Glutathione S-transferase genotyping, glutathione level determination, N-acetyltransferase-2 genotyping and phenotyping were performed. One hundred and thirty-six AIDS patients were studied. Glutathione S-transferase M1 and T1 null genotypes, intracellular glutathione level, slow acetylator genotype and phenotype were not risk factors for cutaneous sulphonamides reactions. The association of glutathione S-transferase M1 null genotype and the slow acetylator one was a risk factor [Fisher's exact test, odds ratio (OR) = 2.6, 95% confidence interval (CI) = 1.2-5.9; P = 0.02]. A discordance between acetylator genotype and phenotype was found in 35% of patients. This frequency was significantly higher than the 6-7% expected (Fisher's exact test: OR = 7.5, 95% CI = 4.2-13.4; P < 0.0001). Suspected metabolic risk factors for sulphonamides cutaneous reactions were not confirmed prospectively. However, the association of glutathione S-transferase M1 null genotype and the slow acetylator one appeared to increase the risk of reactions. We clearly showed that the acetylation phenotype measured by caffeine probe could be modified by the disease.

Cytochrome P450 1B1: a major P450 isoenzyme in human blood monocytes and macrophage subsets

In this study, cytochrome P450 (CYP; EC 1.14.14.1)-dependent activities and P450 isoenzyme patterns were determined in human monocytes and macrophages, which play a major role in antigen processing including small molecular weight compounds which cause contact dermatitis or drug-allergic reactions. Using reverse transcriptase-polymerase chain reaction (RT-PCR) we determined the mRNA expression of eight CYPs (1A1, 1A2, 1B1, 2B6/7, 2E1, 3A3/4, 3A7 and 4B1) in human blood monocytes and macrophage subsets 27E10 and RM3/1. To study the influence of known P450 inducers, monocytes were incubated in vitro with ethanol, dexamethasone, cyclosporin A (CSA), benzanthracene (BA), phenobarbital (PB), lipopolysaccharide (LPS) and 12-O-tetradecanoyl-phorbol-13-acetat (TPA) for 24 hr. Percoll density gradient isolated monocytes as well as the pro-inflammatory macrophage subtype 27E10 expressed 1B1, 2E1 and 2B6/7. On the other hand, in the anti-inflammatory macrophage subtype RM3/1, predominantly 1B1 and to some extent 2B6/7 were found. Treatment with cyclosporin A, phenobarbital, benzanthracene or ethanol resulted in induction of the expression of 3A3/4. CYP1B1 was the predominant isoenzyme in all monocytes and macrophages. In monocytes purified by adherence or induced by benzanthracene, lipopolysaccharide or 12-O-tetradecanoyl-phorbol-13-acetat, 1A1 was also expressed. Northern blot analysis confirmed the presence of CYP1B1 in monocytes and macrophages, a presence which was also demonstrated on the protein level by immunoblot and by immunohistochemical staining of the cells. The expression of several CYPs in monocytes/macrophages suggests that these cells may be important in the metabolism of small molecular weight compounds, which play a role in allergic contact dermatitis and drug reactions. Of particular interest is the remarkably strong expression of the recently identified dioxin inducible CYP1B1, known to be present in a wide range of malignant tumors.

Epidermal N-acetylation of p-aminobenzoyl glutamic acid: difference in response to ultraviolet B irradiation

Arylamine N-acetyltransferases (EC 2.3.1.5) are conjugating drug-metabolizing enzymes and consist of two major isozymes, NAT1 and NAT2. As they have different substrate specificity and expression of polymorphism, distribution of the isozymes may be detected by investigating acetylation. p-Aminobenzoyl glutamic acid (pABG), one of the specific substrates for NAT1 in human pro-monocytic cell-line, was metabolized through acetylation by 9000 x g supernatant fraction from human epidermal keratinocytes and the effect of ultraviolet B (UVB) irradiation on the acetylation was also studied. Forty-eight hours after irradiation of UVB (200 J/m2), the activity was not increased (114 +/- 8.3%, n = 3), while increase in N-acetylating capacity for 2-aminofluorene (substrate for NAT1 and NAT2) amounted to 201 +/- 16% (n = 3). These results suggest that there are at least two isozymes for N-acetylation in the human epidermic and NAT2 may be affected by UVB irradiation.

Epidemiology of drug-induced severe skin reactions

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are severe, sometimes life-threatening skin reactions that are often drug-induced. Unfortunately, the definitions and nomenclature of these severe skin reactions have been confusing, and thus various publications on this issue can hardly be compared. After several attempts have been made to clarify this situation, a consensus definition published in 1993 suggests the differentiation between erythema exsudativum multiforme majus (EEMM) and SJS, as well as an overlap group of SJS and TEN, whereas TEN with maculae is the most severe type of skin reaction with more than 30% of skin detachment related to the body surface area (BSA). This classification was applied to cases of severe skin reactions in several large studies that have been undertaken within the last few years and published recently. The incidence of SJS, SJS/TEN overlap and TEN has been estimated to be approximately 1.89 cases per one million people per year. Although SJS and TEN occur very rarely, a mortality rate of more than 40% can be calculated for patients suffering from TEN. One may conclude that mortality increases with age and the amount of skin detachment related to the BSA. A number of drugs have been reported to induce severe skin reactions, eg, anti-infective sulfonamides, antibiotics, anticonvulsants and nonsteroidal anti-inflammatory drugs. For risk evaluation for certain drugs or drug groups population-based data as ascertained by the German registry of severe skin reactions, and prescription data in defined daily doses can be used. In addition, risk evaluation is possible by performing a case-control study as it has been undertaken within different European countries. As long as the pathogenesis of drug-induced severe skin reactions is not known, and specific screening methods to identify susceptible individuals do not exist, the epidemiological approach will remain the only possibility for risk estimation.

Mechanisms of drug reactions: the metabolic track

Hypersensitivity syndrome (HSR) describes a drug-induced symptom complex consisting of fever, rash, and internal organ involvement. Although these reactions are rare, they are very important because of their severity and unpredictability. The metabolic conversion of drugs to chemically-reactive products is now established as a prerequisite for many idiosyncratic drug reactions. In the setting of HSR, an imbalance in the rates of formation of reactive metabolites and of enzymatic detoxification can lead to accumulation of these byproducts. Reactive metabolites could act as haptens eliciting an immune response, covalently bind target proteins causing cell death, or interact with nucleic acids leading to mutations. The lymphocyte toxicity assay (LTA) provides an in vitro assessment of host susceptibility to reactive metabolites of a given drug. It has validated the clinical finding of increased risk of HSR in first degree relatives of patients. It is hoped that the LTA will be used to predict host susceptibility before drug exposure. Ultimately it is hoped that the genetic defects that lead to drug reactions will be identified. This would improve drug development safety and allow primary prevention of serious reactions.