BACKGROUND: Juvenile dermatomyositis (JDM) and psoriasis are inflammatory disorders that share interferon-alpha induced responses and dysregulation of cytokines, including tumor necrosis factor alpha. Although 13% of patients with JDM have a family history of psoriasis there is little information concerning children with JDM and psoriasis. OBSERVATIONS: We identified 3 children with both JDM and psoriasis. In 2 cases, psoriatic lesions occurred after the child's JDM symptoms had diminished following effective immunosuppressive therapy (high-dose intermittent intravenous methylprednisolone, methotrexate, and low dose oral corticosteroids). Patient 2, initially diagnosed as having psoriasis, was treated with prednisone and methotrexate but then developed classic JDM, which worsened following use of tumor necrosis factor alpha inhibitor and reduction of prednisone and methotrexate dosage. For each child, their history of JDM complicated the choice of therapy for psoriasis. CONCLUSIONS: Two therapies commonly used to treat psoriasis-phototherapy and tumor necrosis factor-alpha antagonists-must be used with caution in patients with both JDM and psoriasis owing to their potential to exacerbate clinical manifestations of JDM. We discuss the implications affecting treatment of children with these dual diagnoses and consider the pathophysiology linking these 2 conditions.