Author: Dr Amanda Oakley, Dermatologist, Hamilton, New Zealand, 1998. Updated by Dr Oakley; Dr Jannet Gomez, Postgraduate Student in Clinical Dermatology, Queen Mary University London, United Kingdom, April 2016.
Pitted keratolysis is a descriptive title for a superficial bacterial skin infection that affects the soles of the feet, and less often, the palms of the hands. It is one of the causes of smelly feet. It is characterised by whitish skin and clusters of punched-out pits.
Pitted keratolysis is caused by several bacterial species, including corynebacteria, Dermatophilus congolensis, Kytococcus sedentarius, actinomyces and streptomyces.
The bacteria proliferate in moist conditions. The pitting is due to destruction of the horny cells (stratum corneum) by protease enzymes produced by the bacteria.
The bad smell is due to sulfur compounds produced by the bacteria: thiols, sulfides and thioesters.
Pitted keratolysis is much more common in males than in females. Occupations at risk include:
Females offering pedicure and foot care in a spa salon may also be affected by pitted keratolysis.
Factors that lead to the development of pitted keratolysis include:
The result is very smelly feet, due to infection of the soles. Either the forefoot or the heel or both become white with clusters of punched-out pits. The appearance is more dramatic when the feet are wet. Very rarely, the fingers are similarly affected. There is a variant of pitted keratolysis where there are more diffuse red areas on the soles.
The most commonly reported symptom is malodour. The pits themselves are usually asymptomatic but may cause soreness or itching when walking.
Pitted keratolysis is usually diagnosed clinically. Swabs are rarely required. However, the causative organisms may be identified from the pitted lesions and cultured on brain heart infusion agar.
Skin scrapings are often taken to exclude fungal infection. Wood light examination displays a characteristic coral red fluorescence in some cases.
Oral erythromycin is also helpful.
Pitted keratolysis will quickly recur unless the feet are kept dry. The following precautions should be taken to prevent recurrences:
Wear boots for as short a period as possible
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