A 26-year-old woman presented with pain and discoloration in the fingertips of both hands on exposure to cold (Panels A and B). She had had the same symptoms every winter for the past decade. The patient's history and physical examination revealed no signs or symptoms suggestive of systemic lupus erythematosus or scleroderma. She reported that she did not smoke. Her history of a sudden onset of the symptoms is consistent with a diagnosis of Raynaud's phenomenon. Raynaud's phenomenon is characterized by exaggerated vasoconstrictive color changes (pallor and cyanosis) in the fingers, usually due to exposure to cold. The phenomenon is considered primary if there is no evidence of an underlying medical illness. Secondary Raynaud's phenomenon occurs in association with another condition, such as systemic lupus erythematosus, scleroderma, or peripheral vascular disease. The patient was given a recommendation to keep her hands warm to avoid further attacks. Although pharmacologic treatments such as calcium-channel blockers, topical nitroglycerin, sildenafil, and other vasodilators may play a part in the management of Raynaud's phenomenon, this patient did not require any medications for the management of her attacks. Michael Rodgers, M.D. University Medical Center Groningen, Groningen, the Netherlands