What is the pathophysiology of pitted keratolysis?

Updated: Jul 30, 2018
  • Author: Linda J Fromm, MD, MA, FAAD; Chief Editor: Dirk M Elston, MD  more...
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Answer

Pitted keratolysis is caused by a cutaneous infection with Micrococcus sedentarius (now renamed to Kytococcus sedentarius); Dermatophilus congolensis; or species of Corynebacterium,Actinomyces, or Streptomyces. [4, 5, 6, 7] Under appropriate conditions (ie, prolonged occlusion, hyperhidrosis, increased skin surface pH), these bacteria proliferate and produce proteinases that destroy the stratum corneum, creating pits. [8] D congolensis liberates keratinases in appropriate substrate. [9, 10, 11] K sedentarius has been found to produce 2 keratin-degrading enzymes. They are protease P1 (30 kd) and P2 (50 kd). [7] The malodor associated with pitted keratolysis is presumed to be the production of sulfur-compound by-products, such as thiols, sulfides, and thioesters. [12]

In 2006, foot odor without pitted skin changes was discovered to be from overgrowth of Bacillus subtilis and specifically an isovaleric acid produced by Staphylococcus epidermidis overgrowth, a normal skin flora. [13]


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