Pitted keratolysis in Adult
Affected areas are generally asymptomatic but can emit a foul odor due to the production of isovaleric acid by the bacterial metabolism of the leucine in sweat. Rarely, pruritus, pain, or burning may be present. Predisposing factors are excessive sweating and prolonged occlusion in a warm, humid environment. Although rare, the hands may be affected.
L08.89 – Other specified local infections of the skin and subcutaneous tissue
51212009 – Pitted keratolysis
Differential Diagnosis & Pitfalls
- Tinea pedis – Usually scaly and erythematous. Hyphal elements can be demonstrated using a potassium hydroxide (KOH) preparation.
- Tinea nigra – Presents with a black pigmented patch.
- Dyshidrotic eczema – Presents with pruritus, scale, and pinpoint vesicles on the palms, soles, and lateral digits.
- Subacute and chronic hand and foot eczema, including nummular and contact dermatitis.
- Punctate keratoderma – Has firm keratotic papules.
- Webspace erythrasma – Typically hyperkeratotic but can be erosive. This shows coral-red fluorescence on Wood's lamp examination. Concomitant erythrasma and pitted keratolysis may be seen.
- Mosaic warts – Show more vascularity and sometimes the black dots of thrombosed capillaries.
- Arsenic toxicity – Pitting is associated with the other features of arsenism such as teardrop pigmentation.
- Nevoid basal cell carcinoma syndrome (Gorlin syndrome) – Palmoplantar pits can be seen but usually in the presence of other stigmata of the condition, including odontogenic keratocysts and numerous basal cell carcinomas, among other findings.