Mesna-induced photodistributed dermatosis.

We present the case of a 41-year-old man who developed a photodistributed eruption 1 month after being started on 2-mercaptoethane sulfonate sodium (mesna) for treatment of cyclophosphamide-induced haemorrhagic cystitis. The patient had a background history of Wegener granulomatosis, and had been taking cyclophosphamide at a stable dose of 150 mg daily for the previous 3 years. Complete resolution of the rash occurred within 8 weeks of cessation of mesna. This is the first reported case, to our knowledge, of mesna-induced photodistributed dermatosis. Early recognition of this condition will ensure prompt cessation of the culprit medication, and consideration of alternative management of haemorrhagic cystitis.