[Auto-immune thyroiditis and drug reaction with eosinophilia and systemic symptoms (DRESS) associated with HHV-6 viral reactivation].

INTRODUCTION: DRESS syndrome is a severe adverse drug reaction with visceral involvement. Its physiopathology includes immunological disorders associated with human herpes virus (HHV) reactivation. We report two cases of auto-immune thyroiditis occurring in the context of DRESS syndrome associated with HHV-6 reactivation. OBSERVATIONS: Case 1 : A 39-year-old woman presented DRESS syndrome with HHV-6 reactivation, cutaneous, lymph node, hepatic and renal disorders treated with systemic corticosteroids for 10 months. Following discontinuation of the corticosteroids, she developed Graves's disease, which was stabilized with carbimazole and a beta-blocker. CASE 2: A 31-year-old woman was hospitalized for DRESS syndrome with delayed HHV-6 reactivation and severe hepatic involvement. She was successfully treated by topical steroids. Six weeks later, she presented De Quervain thyroiditis associated with moderate relapsing DRESS, which were treated by sodium levothyroxine and topical steroids. DISCUSSION: There is currently debate about the implication of viral reactivation, in particular HHV-6, in chronic DRESS, relapse and development of auto-immune diseases. These observations highlight the potential risk of patients developing auto-immune diseases and underline the need for prolonged clinical and laboratory follow-up of patients with DRESS.