Ms. A, a 20-year-old woman with obsessive-compulsive disorder (OCD) and a history of migraines, began treatment with paroxetine, 10 mg/day. She had no other past medical or psychiatric history and was receiving no other medications. Her dose of paroxetine was increased to 20 mg/day after 2 weeks. After 6 weeks of treatment she reported a "shaking feeling all over," insomnia, and a worsening of her migraines. Lorazepam, 1 mg/day as needed, was added to treat the insomnia. At 10 weeks her paroxetine dose was decreased to 10 mg/day because the migraines and "shaking feeling" continued. At 15 weeks she developed multiple painful purple lesions of the extremities of several digits on both hands. The remainder of her physical examination was unremarkable. Treatment with paroxetine was discontinued.

One week later the lesions disappeared. Paroxetine was reintroduced at 10 mg/day; 2 days later the vasculitic reactions returned. They disappeared again 1 week after a second cessation of paroxetine. Laboratory investigations, including a CBC and tests for electrolyte levels and renal and liver function performed 3 weeks after paroxetine was discontinued, were normal except for an elevated erythrocyte sedimentation rate of 34 mm/hour (normal=0–20 mm/hour) and a low alkaline phosphatase level of 34 IU/liter (normal=42–121 IU/liter). The results of tests for C-reactive protein and rheumatoid factor performed 3 months later were negative.