A case of hydroxyzine-induced fixed drug eruption and cross-reactivity with piperazine derivatives

We report a case of hydroxyzine-induced fixed drug eruption and cross-reactivity with piperazine derivatives. A 72-year-old woman presented with a recent onset of flaccid bullae over erythematous patches on her hands, feet and back; large rounded pigmented patches were noted. A diagnosis of bullous fixed drug eruption was raised. The only drug she began taking recently was hydroxyzine. Her past medical history included similar episodes after taking fluoroquinolones and antihistamines (levocetirizine and cetirizine); desloratadine and loratadine had been well tolerated. A histological examination of her skin showed keratinocyte necrosis compatible with a bullous fixed drug eruption. Patch-tests performed with hydroxyzine, cetirizine, levocetirizine and fluoroquinolones (concentration at 30% in water and in vaseline) were negative in successive readings at 48, 72 and 96 hours, both in pigmented scars and in healthy skin. These diverse molecules were nevertheless held responsible for the bullous fixed drug eruptions. For this reason, a document listing these drugs as contraindicated was given to the patient. A few months later, the fortuitous injection of levocetirizine before having a CT scan caused a new bullous eruption, with all the typical lesions of a fixed drug eruption. (C) 2016 Elsevier Masson SAS. All rights reserved.