A previously healthy 40-year-old man complains of worsening lower-extremity discomfort. He noticed the discomfort several days earlier on awakening and thought that he had been bitten by a spider. The lesion, initially a small pustule, has enlarged into an open wound.

For several months, a 45-year-old woman has had ocular irritation, tearing, blurred vision, and swelling of the eyelids in both eyes. A close-up view of her eyelashes is shown here.

These scaly plaques on the scalp of a 32-year-old man have failed to respond to a topical antifungal. The patient has a 3-year history of pulmonary sarcoidosis.

A 24-year-old man is concerned about a large, hairy "mole" on his left shoulder. The lesion appeared during adolescence as a group of small, dark blotches. These eventually coalesced into a hyperpigmented patch with hair and acne.

A linear, severely pruritic rash erupted on the lateral and plantar aspects of the left foot of a 72-year-old woman who had recently been camping on a Caribbean beach. Antihistamines and locally applied antifungal agents offered no relief.

During a routine physical examination, a 3-mm dark brown streak is noted on the fourth toe of a 54-year-old man.