Photo Quiz

Unpleasant Foot Odor and Skin Changes


Am Fam Physician. 2019 May 15;99(10):651-652.

A 24-year-old woman presented with several months of increasingly problematic foot odor. She noted that there were accompanying skin changes on the soles of her feet but no itching, redness, or discharge. She had no improvement with use of various deodorants, frequent washing, and frequent sock changes. When coworkers complained about the odor, she presented for evaluation.

Physical examination revealed small pits in the skin on her soles (Figure 1) along with the foot odor. There was a slight scale over the plantar surface of both feet. Wood light examination did not show fluorescence but showed that the pits were more extensive than what was apparent with room light (Figure 2).

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Based on the patient's history and physical examination findings, which one of the following is the most likely diagnosis?

A. Hyperhidrosis.

B. Palmoplantar hyperkeratosis.

C. Pitted keratolysis.

D. Tinea pedis.


The answer is C: pitted keratolysis. The combination of pits on the weight-bearing areas of the feet and a very unpleasant foot odor is a hallmark of this condition. Pitted keratolysis most often occurs in individuals whose feet have excessive exposure to a damp environment, such as with hyperhidrosis (excessive sweating), frequent immersion in water, or occlusive footwear in a hot environment. The skin becomes macerated and develops bacterial overgrowth. Several bacterial species have been identified as causative agents. Some of these can cause fluorescence on Wood light examination if the feet have not been recently washed. The odor is thought to be due to the breaking of sulfhydryl bonds in the keratin layer.1

Treatment of pitted keratolysis is directed at the bacterial infection, as well as decreasing the risk factors for the condition. Wetness from hyperhidrosis

Address correspondence to William F. Keenan Jr., MD, at Reprints are not available from the author.

Author disclosure: No relevant financial affiliations.


1. Goldsmith LA, Katz SI, Gilchrest BA, et al., eds. Fitzpatrick's Dermatology in General Medicine 8th ed. New York, NY: McGraw-Hill; 2012:2145–2146.

2. Barankin B, Leung AK. Pitted keratolysis. UpToDate [login required]. Accessed June 8, 2018.

3. Strutton DR, Kowalski JW, Glaser DA, Stang PE. US prevalence of hyperhidrosis and impact on individuals with axillary hyperhidrosis: results from a national survey. J Am Acad Dermatol. 2004;51(2):241–248.

This series is coordinated by John E. Delzell Jr., MD, MSPH, Associate Medical Editor.

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