Acute generalized exanthematous pustulosis: European expert consensus for diagnosis and management.

Acute generalized exanthematous pustulosis (AGEP) is a rare, usually drug-induced, acute pustular rash. Despite the lack of strong data supporting the effectiveness of topical or systemic corticosteroids in this drug reaction, they are widely used. More generally, there is no consensus on the diagnostic modalities and the management of patients with AGEP. We aimed to provide European expert recommendations for the diagnosis and management or patients with AGEP. Members of the ToxiTEN group of the European Reference Network (ERN)-skin, all dermatologists and/or allergologists with expertise in drug reactions, elaborated these recommendations based on their own experience and on a review of the literature. Recommendations were separated into the following categories: professionals involved, assessment of the diagnosis of AGEP, management of the patient and allergological work-up after the acute phase. Consensus was obtained among experts for the list of professionals involved for the diagnosis and management of AGEP, including the minimum diagnostic work-up, the setting of management, the treatments, the modalities and the timing of allergological work-up and follow-up. European experts in drug allergies propose herein consensus on the diagnosis and management of patients with AGEP. A multidisciplinary approach is warranted, including dermatologists, allergologists and pharmacovigilance services.

Retrospective study on the association of human herpesvirus reactivation with severe DRESS: A description of blood and skin reactivations.

BACKGROUND: Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) is a severe adverse event (mortality of 10%). Its pathophysiology involves herpesviruses, particularly HHV-6, but the exact mechanisms are still poorly understood. OBJECTIVE: To describe severe cases of DRESS and especially their association with herpesvirus reactivation. METHODS: This study was a multicentre case series conducted between 2007 and 2021 at five University Hospital Centres in France. The study included patients who had severe DRESS, which was defined as death, transfer to the intensive care unit (ICU), or severe damage to internal organs. We excluded patients without blood PCR sample, without a drug formally attributed or with RegiSCAR score < 6. We collected data on severity, causative drug, associated visceral damage and results of viral blood PCRs. HHV-6 reactivation was studied in skin biopsies by detection of small non-coding transcripts (HHV-6 miR-aU14) and a late viral protein (GP82/105). RESULTS: Fifty-two patients were included (29 female, median age 62, interquartile range (IQR) [37;72]). Eight patients (15%) died, 13 (27%) were admitted to ICU. Most patients (n = 34; 65%) had multisystem involvement: most frequent was liver (n = 46; 88%), then renal failure (n = 24; 46%). Forty patients (77%) had at least one blood viral reactivation among HHV-6, EBV or CMV, of which 21 (53%) had at least two. Median time of blood HHV-6 reactivation was 24 days (IQR [20;35]). HHV-6 reactivation was demonstrated in 15 out of 20 skin biopsies, with a median time of 11 days [9;17]. CONCLUSIONS: We confirmed the high rate of HHV-6 reactivation in severe DRESS and demonstrated cutaneous HHV-6 reactivation using small non-coding transcripts (HHV-6 miR-aU14), which preceded viral PCR positivity in blood. These results suggest that HHV-6 reactivation during DRESS may start in skin. Furthermore, search for miR-aU14 in skin biopsy could become a useful diagnostic tool for early detection of HHV-6 reactivation.

Towards a better understanding of adult idiopathic epidermal necrolysis: a retrospective study of 19 cases.

BACKGROUND: Most cases of Stevens-Johnson syndrome and toxic epidermal necrolysis are drug-induced. A small subset of cases remain with unknown aetiology (idiopathic epidermal necrolysis [IEN]). OBJECTIVE: We sought to better describe adult IEN and understand the aetiology. METHODS: This retrospective study was conducted in 4 centres of the French national reference centre for epidermal necrolysis. Clinical data were collected for the 19 adults hospitalized for IEN between January 2015 and December 2019. Wide toxicology analysis of blood samples was performed. Histology of IEN cases was compared with blinding to skin biopsies of drug-induced EN (DIEN, 'controls'). Available baseline skin biopsies were analysed by shotgun metagenomics and transcriptomics and compared to controls. RESULTS: IEN cases represented 15.6% of all EN cases in these centres. The median age of patients was 38 (range 16-51) years; 68.4% were women. Overall, 63.2% (n = 12) of cases required intensive care unit admission and 15.8% (n = 3) died at the acute phase. Histology showed the same patterns of early- to late-stage EN with no difference between DIEN and IEN cases. One toxicology analysis showed unexpected traces of carbamazepine; results for other cases were negative. Metagenomics analysis revealed no unexpected pathological microorganism. Transcriptomic analysis highlighted a different pro-apoptotic pathway in IEN compared to DIEN, with an overexpression of apoptosis effectors TWEAK/TRAIL. CONCLUSIONS: IEN affects young people and is a severe form of EN. A large toxicologic investigation is warranted. Different pathways seem involved in IEN and DIEN, leading to the same apoptotic effect, but the primary trigger remains unknown.

Childhood epidermal necrolysis and erythema multiforme major: a multicentre French cohort study of 62 patients.

INTRODUCTION: The distinction between epidermal necrolysis [EN; including Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN) and overlap syndrome] and erythema multiforme major (EMM) in children is confusing. We aimed to better describe and compare these entities. MATERIALS AND METHODS: This French retrospective multicentre study included children ≤18 years old referred for EN or EMM between 1 January 2008 and 1 March 2019. According to pictures, children were reclassified into TEN/overlap, SJS or EMM/unclassified (SJS/EMM) groups and compared for epidemiological and clinical data, triggers, histology and follow-up. RESULTS: We included 62 children [43 boys, median age 10 years (range 3-18)]: 16 with TEN/overlap, 11 SJS and 35 EMM. The main aetiologies were drugs in EN and infections (especially Mycoplasma pneumoniae) in EMM (P < 0.001), but 35% of cases remained idiopathic (TEN/overlap, 47%; SJS, 24%; EMM, 34%). The typical target lesions predominated in EMM (P < 0.001), the trunk was more often affected in EN (P < 0.001), and the body surface area involved was more extensive in EN (P < 0.001). Mucosal involvement did not differ between the groups. Two patients with idiopathic TEN died. Histology of EMM and EN showed similar features. The recurrence rate was 42% with EMM, 7% with TEN/overlap and 0 with SJS (P < 0.001). Sequelae occurred in 75% of EN but involved 55% of EMM. CONCLUSION: Clinical features of EN and EMM appeared well demarcated, with few overlapping cases. Idiopathic forms were frequent, especially for EN, meaning that a wide and thorough infectious screening, repeated if needed, is indicated for all paediatric cases of EN/EMM without any trigger drug. We propose a comprehensive panel of investigations which could be a standard work-up in such situation. Sequelae affected both EN and EMM.

[Severe immediate hypersensitivity reaction with generalized contact urticaria after cutaneous application of topical permethrin]. / Réaction d'hypersensibilité immédiate sévère avec urticaire de contact généralisée secondaire à l'application cutanée de perméthrine topique.

BACKGROUND: Permethrin is a synthetic pyrethroid used as a chemical insecticide that obtained an MA in the management of human scabies in 2014. We report a case of severe immediate hypersensitivity (IH) reaction with generalized contact urticaria secondary to the cutaneous application of 5% permethrin cream (Topiscab®). OBSERVATION: A 44-year-old woman with no personal history of atopy was treated with oral ivermectin, Topiscab® and levocetirizine for suspected scabies. Eight hours after taking a levocetirizine tablet and five hours after the application of a tube of Topiscab® together with oral ivermectin, she presented generalized urticaria, nausea and diarrhoea, followed by loss of consciousness. Skin prick-tests for ivermectin and levocetirizine were negative. We noticed non-significant erythema with permethrin. The open application test with Topiscab® was strongly positive at 20min with the appearance of an urticaria plaque in the area of application. The open test with sorbic acid was positive at 2h. Accidental exposure to permethrin spray caused dyspnoea and recurrence of urticaria. DISCUSSION: Mild and transient symptoms are regularly described after cutaneous application (burning, paraesthesia or increased itching). Delayed hypersensitivity reactions such as contact dermatitis have been reported in the literature. Exceptional cases of severe IH reactions have been described following occupational exposure to airborne pyrethroid insecticides. No cases of severe IH reaction secondary to application of topical permethrin have been reported.

Severe cutaneous adverse reactions due to inappropriate medication use.

BACKGROUND: The proportion of severe cutaneous adverse reactions (SCARs) that could be avoided if medication use was consistent with good medical practice is unknown. OBJECTIVES: To estimate the proportion of SCARs related to inappropriate medication use. METHODS: We carried out a retrospective study of all validated SCARs collected in a French registry between 2003 and 2016. For each case, all plausible drugs suspected of inducing SCARs (i.e. not just the drug regarded as 'the most probable') were considered with regard to (i) prescription for an inappropriate indication, (ii) unintentional rechallenge despite a previous allergy to the drug or (iii) self-medication with prescription medicines. RESULTS: In total, 602 cases were included in the analyses. Antibiotics, anticonvulsants and allopurinol were the drugs most frequently involved, accounting for more than 50% of all cases. All suspected medications were considered to have been appropriately used for 417 of the 602 individuals included in the study population [69·3%, 95% confidence interval (CI) 65·6-73·0] and inappropriately used for 144 individuals (23·9%, 95% CI 20·5-27·3). These inappropriate uses were due mainly to prescriptions for an inappropriate indication (65·8%, 95% CI 58·4-73·2) or unintentional rechallenge (20·9%, 95% CI 14·6-27·2). Allopurinol and co-trimoxazole were the drugs most frequently involved in inappropriate indications. Antibiotics were the largest group involved in unintentional rechallenge. Nonsteroidal anti-inflammatory drugs, available on prescription, were most frequently involved in inappropriate self-medication. CONCLUSIONS: Our results underline the need for respecting the appropriate indication for drugs in order to reduce the incidence of SCARs. Reducing unintentional rechallenge also seems to be a necessary preventive measure.

Recurring acute urticaria and abdominal pain: Consider a diagnosis of alpha-galactose anaphylaxis.

BACKGROUND: Food urticaria is common and generally benign, and it may be of viral or idiopathic aetiology. A food origin of the allergy is frequently sought but rarely found. Mammalian meat anaphylaxis, or alpha-galactose (α-gal) anaphylaxis, is a rare and recently discovered entity. PATIENTS AND METHODS: Herein, we report a case of alpha-galactose (α-gal) anaphylaxis in a 60-year-old woman presenting four episodes of acute urticaria with signs of anaphylaxis occurring a few hours after meals containing mammalian meat (beef meat, pork meat and offal). The diagnosis was confirmed by a positive gelatine prick-test and the presence of α-gal IgE. DISCUSSION: In the event of acute urticaria associated with systemic symptoms, in particular gastrointestinal signs, allergy to α-galactose should be considered.