[Hydroxychloroquine-not always a harmless drug for off label use in dermatology].

Hydroxychloroquine is used for treatment of inflammatory diseases. It is considered to have few adverse effects. We report on a woman who developed a severe skin rash after intake of hydroxychloroquine, which she received for treatment of her lichen planopilaris. Based on the clinical, laboratory and histological findings the diagnosis of a drug reaction with eosinophilia and systemic symptoms (DRESS)-like drug reaction was established. Our case illustrates that hydroxychloroquine can lead to severe adverse effects in rare cases and that patients receiving this drug must be thoroughly informed.