By Gary M. White, MD

Pitted keratolysis Worm-eaten grooves and depressions on the sole.

Pitted keratolysis (PK) is a bacterial proliferation on the surface of the skin in which the superficial keratin layer is eaten away. A chronically moist environment allows any of a variety of bacteria to grow including corynebacteria, Kytococcus sedentarius (which can secrete a protease with callous-degrading activity) and others.

Some patients may be affected by the so called corynebacterial triad:


Small 1-2 mm pits, reticulated erosions, or extensive loss of the hyperkeratotic outer layer on the sole or toes in a teenager who wears shoes all day and whose feet sweat is characteristic. The palms may rarely be affected and present as ringed collarettes.

Malodor and sliminess of the skin occur in the majority of cases. The most common sites of onset of PK are the pressure-bearing areas, such as the ventral aspect of the toe, the ball of the foot, and the heel. The next most common site is a friction area, the interface of the toes. Lesions are rarely seen on the non-pressure-bearing locations. [BrJ Dermatol 1997 Aug;137(2):282-5].  


Erythromycin or clindamycin topically are effective. Aluminum chloride 20% or other methods to reduce hyperhidrosis can help. Prolonged use of occlusive footwear should be avoided.

Additional Pictures

Pitted keratolysis Pitted keratolysis

Pitted keratolysis Pitted keratolysis


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