Reiter's syndrome, also known as reactive arthritis, is the classic triad of conjunctivitis, urethritis, and arthritis occurring after an infection, particularly those in the urogenital or gastrointestinal tract. Dermatologic manifestations are common, including keratoderma blennorrhagicum, circinate balanitis, ulcerative vulvitis, nail changes, and oral lesions. Epidemiologically, the disease is more common in men, although cases have also been reported in children and women. The pathophysiology has yet to be elucidated, although infectious and immune factors are likely involved. Clinical presentation, severity, and prognosis vary widely. Treatment is difficult, especially in HIV-positive patients. Prognosis is variable; 15% to 20% of patients may develop severe chronic sequelae.