[Lethal Lyell's syndrome induced by fusidic acid]. / Syndrome de Lyell à l'acide fusidique oral d'évolution fatale.

BACKGROUND: Herein, we report the first case of toxic epidermal necrosis due to oral fusidic acid having a fatal outcome. PATIENTS AND METHODS: An 82-year-old woman was referred to our dermatology department for generalized bullous skin eruption. Clinical examination showed fever, oral and ocular ulcerations, and epidermal detachment involving more than 70 % of her body surface area together with a positive Nikolsky sign. Lyell's syndrome was diagnosed. Cutaneous histology showed total epidermal necrosis and a normal dermis. Oral fusidic acid had been prescribed 12 days earlier for a chronic sacral pressure sore. No other treatment had been introduced during the previous two months. The outcome was fatal within 24 hours. DISCUSSION: Fusidic acid is commonly used topically by dermatologists for limited staphylococcal skin infections. Oral treatment is rare and is recommended only for skin, bone or joint infections. This is the first reported case of toxic epidermal necrolysis due to oral fusidic acid. The French national drug safety monitoring register contains only one case in which fusidic acid was a possible culprit. CONCLUSION: Fusidic acid must be considered a potential source of serious cutaneous adverse reactions, particularly toxic epidermal necrolysis.

[Acantholytic dermatosis in patients treated by vemurafenib: 2 cases]. / Deux cas de dermatose acantholytique sous vémurafénib.

BACKGROUND: Acantholytic dyskeratosis under BRAF inhibitors are dermatological diseases rarely reported to date. PATIENTS AND METHODS: We report 2 cases of acantholytic dyskeratosis, reaching the trunk and the seborrheic zones, not itchy, appeared one month after the introduction of vemurafenib. The histological analysis was typical of a "Grover-like rash" for the 2 patients. DISCUSSION: The appearance of acantholytic dyskeratosis under vemurafenib, a BRAF inhibitor, seems related with a paradoxical activation of the MAP-kinases pathway and with a growth acceleration of lesions in which RAS mutations of keratinocytes. Theses dermatoses seem also to occur with dabrafenib. CONCLUSION: The patients treated by BRAF inhibitors (vemurafenib and dabrafenib) can present acantholytic dyskeratosis. The arisen of this mild dermatosis does not question, of course, the continuation of the treatment. These cutaneous manifestations can be managed with emollients.