A 47-year-old man first noticed the rash on his right palm about 20 years ago. Since then, it has recurred—usually flaring in the summertime—but has remained largely asymptomatic. The rash manifests with tiny papules, many of which develop into slightly larger blisters that gradually resolve over a period of weeks to months.

Upon questioning, the patient reports that the rash initially manifested shortly after he had joined the military—at which time he also developed a rash on the soles of both feet. Assuming the problem was fungal, he tried applying several OTC creams and even soaked his feet in bleach. Similarly, over the years he has attempted to treat his palmar rash with various prescribed and OTC steroid creams, as well as using OTC topical antifungal creams. None of these efforts have proved fruitful.

The patient claims to be in otherwise good health. He states he is not prone to rashes, seasonal allergies, or sensitive skin.

On examination, the entire right palmar surface is covered by 2-to-3-mm intradermal papules and vesicles, none of which are tender to touch. There is no increased warmth or redness. The dorsal aspect of his hand is totally uninvolved, as are all his fingernails. No notable skin changes are seen on his elbows, knees, or scalp.

KOH examination of the plantar vesicles shows numerous fungal elements, while KOH of the palmar vesicles is negative for fungi.