Intro: Dermatology department of Henri Mondor Hospital (Creteil, France), is a reference center for toxic bullous diseases and severe cutaneous drug reactions (Stevens-Johnson syndrome (SJS), Lyell syndrome (toxic epidermal necrolysis (TEN)), generalized bullous fixed drug reactions, AGEP, DRESS, drug induced immunoglobulin A (IgA) bullous dermatosis, and erythema multiforme). In order to conduct clinical and biological research studies in drug reactions, it is necessary for the investigator's department to implement a collection of clinical data and biological samples.

Hypothesis/Objective: To collect clinical data and cutaneous and biological samples for immunological, biological and genetic studies to improve knowledge about pathophysiology of drug reactions.

Method: The following samples will be performed in addition to the routine practice samples: one skin punch biopsy (6mm); 43 mL of blood; blister fluid aspiration; oral and nose mucous membrane and skin eSWABs, stool samples.

These samples will be stored in a dedicated biological sampling department ("Platform of biological resources").

Conclusion: The implementation of this collection should allow us to conduct pathophysiological studies about drug reactions.

Inclusion Criteria:

• Patient ≥ 18 y-old
• Severe cutaneous drug reaction (AGEP, DRESS, SJS/TEN, generalized bullous fixed drug eruption), drug-induced IgA bullous dermatosis, maculopapular exanthema, erythema multiforme
• Signed consent
• Social security affiliation

Exclusion Criteria:

• Patients law protection

Patients with severe cutaneous adverse reactions (DRESS, AGEP, SJS/TEN, generalized bullous fixed drug eruption), drug-induced IgA linear dermatosis, maculo-papular exanthema, erythema multiforme.