Rupioid psoriasis on the hands

A 42-year-old man with a history of psoriasis vulgaris was referred to a dermatology department with 6 weeks of worsening psoriasis. He had started treatment for bipolar disorder with valproic acid 4 months prior. The patient had crusty, adherent plaques with reddish, sharply demarcated borders on the back of both hands. He diagnosed rupioid psoriasis based on the skin lesions and his history of psoriasis and valproic acid intake. The differential diagnosis included secondary syphilis, histoplasmosis, scabies and HIV, all of which have been associated with similar lesions. His syphilis and HIV serology were negative. the patient had responded well to methotrexate in the treatment of previous psoriatic flares; he was prescribed methotrexate 15 mg/wk. After 2 months, his lesions resolved completely and they began tapering the methotrexate. Patients with rupioid forms of psoriasis should have a careful drug history taken, along with HIV and syphilis testing. The relative benefits of intensifying psoriasis treatment versus withdrawal of triggering drugs should be evaluated, ideally with the help of a multidisciplinary team.