Pictorial case study: Itchy feet

Contributed by Dr Jean Watkins, a sessional GP in Hampshire.

The case
This young man attended the surgery in great distress. His girlfriend was refusing to see him if he did not do something about his smelly feet. They itched at times and were also tender. On examination, the magnitude of his problem became apparent. The offensive smell that emanated from his sweaty feet was overpowering. The soles of his feet displayed a symmetrical pattern of reddish/purple discolouration, with areas of small pits. The discolouration covered the weight-bearing areas of his feet. What is the diagnosis, management and differential diagnoses?

Diagnosis and management
A diagnosis of pitted keratolysis seemed clear. A skin scraping was taken from the affected area to confirm the presence of Kytococcus sedentarius or corynebacterium and actinomycoses, which cause the problem, and to exclude the possibility of tinea. Pitted keratolysis is a common problem at any age, in those that wear occlusive footwear such as trainers and boots. He was advised to discontinue these and to wear absorbent cotton socks that he could change frequently, so that sweat would be more easily absorbed.

Apart from this, he was encouraged to soak his feet twice a day in a 5 per cent solution of formalin and to use a roll-on antiperspirant such as 20 per cent aluminium chloride. Should this be insufficient he could apply a topical antibiotic such as fusidic acid, erythromycin or clindomycin twice a day and if it persisted oral erythromycin 250mg four times a day should settle it within a few weeks. The possibility of iontophoresis was mentioned.

Possible different diagnoses

  • Plantar warts
  • Tinea pedis
  • Exfoliative keratolysis
  • Hyperkeratosis

Differential diagnosis
Exfoliative keratolysis (focal palmar peeling):

  • Skin condition that causes peeling of the soles of feet, or more usually the palm of the hand.
  • Usually affects young adults and tends to occur in the warmer seasons.
  • Exacerbated by exposure to irritants such as water, soaps or detergents.
  • Initially small, white, air-filled blisters appear. When they burst, they leave circular areas of desquamation. Itching is not usually a problem.
  • These dry areas become cracked and red.
  • Has a tendency to recur.
  • Sometimes precedes pompholyx eczema, in which there are fluid-filled blisters.
  • Skin scrapings exclude tinea.

 

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