A recent study has shown that certain drug allergies were actually related to an immune system against certain viruses. The aim of the study is to evaluate, in patients taking antiepileptic drugs, if this treatment induces proliferation of these viruses and secondarily an immune response that would promote the development of a rash. In particular, will be studied whether these drugs can induce virus reactivation "dormant" in the immune system. This study will not affect the usual follow-up proposed by investigators, with the exception of some additional blood samples.

Inclusion Criteria:

• Patients age over 18 years
• Patient for whom treatment of antiepileptic class will be started or was set for less than 48 hours and including one of the following molecules (as princeps or generic equivalent form): sodium valproate, divalproate sodium, valpromide, lamotrigine, carbamazepine, oxcarbazepine eslicarbazepine acetate.
• Patient or patient's representative who was informed and signed the consent form
• Effective contraception in women of childbearing age
• Affiliation to health insurance

Exclusion Criteria:

• Immunosuppressive therapy in progress or acquired immunodeficiency
• Patient with meningitis or meningoencephalitis
• Patient with known contraindications to any molecules indicated in the study
• Major Patient protection (guardianship) or deprived of liberty by judicial or administrative decision.
• Patient participating in another clinical trial or participated in another trial in the month before.
• Pregnant or breastfeeding women.