Procedures

Skin biopsies are not performed routinely because the diagnosis of pitted keratolysis can be made easily by means of visual examination and recognition of the characteristic odor. Wood lamp examination is of limited use because results are inconsistent.^{[38, 39]}

Histologic Findings

If a cutaneous biopsy is performed, histological evaluation of hematoxylin and eosin (H&E)–stained plantar skin reveals a crater limited to the stratum corneum (see the image below).

Histopathology reveals a crater limited to the thick stratum corneum of the epidermis.

View Media Gallery

The microorganisms, cocci, and filamentous forms may be seen with H&E staining, but they are detected more easily with Gram stain, periodic acid-Schiff stain, or methenamine silver stain. In 2000, Wohlarb et al reported 2 histologic types.^[15]The superficial minor type is coccoid bacteria found extracellularly on the surface of the stratum cornea. The classic or major type is coccoid and septated bacterium forms intracorneocytically in the horny layer. In patients with associated foot pain and with erythematous-to-violaceous macular lesions and pits, histological examination reveals only a mild dermal inflammatory reaction. In 2000, de Almeida et el studied pitted keratolysis with electron microscopy and noted transverse septated bacterium in tunnellike openings on the floor of the pits.^[40]

Treatment & Management

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Media Gallery

A large plaque-like lesion of Pitted keratolysis on the large toe.
A case of inflammatory pitted keratolysis
Pitted keratolysis with hyperkeratosis on the heel.
Classic pits of pitted keratolysis on the plantar aspect of the phalanges.
Pitted keratolysis forming sulci on the heel.
Histopathology reveals a crater limited to the thick stratum corneum of the epidermis.

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Author

Linda J Fromm, MD, MA, FAAD Private Practice, Fromm Dermatology at Health Concepts; Dermatologist, Rapid City Medical Center

Linda J Fromm, MD, MA, FAAD is a member of the following medical societies: American Academy of Dermatology

Disclosure: Nothing to disclose.

Specialty Editor Board

David F Butler, MD Former Section Chief of Dermatology, Central Texas Veterans Healthcare System; Professor of Dermatology, Texas A&M University College of Medicine; Founding Chair, Department of Dermatology, Scott and White Clinic

David F Butler, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, Association of Military Dermatologists, Phi Beta Kappa, Texas Dermatological Society

Disclosure: Nothing to disclose.

Edward F Chan, MD Clinical Assistant Professor, Department of Dermatology, University of Pennsylvania School of Medicine

Edward F Chan, MD is a member of the following medical societies: American Academy of Dermatology, American Society of Dermatopathology, Society for Investigative Dermatology

Disclosure: Nothing to disclose.

Chief Editor

Dirk M Elston, MD Professor and Chairman, Department of Dermatology and Dermatologic Surgery, Medical University of South Carolina College of Medicine

Dirk M Elston, MD is a member of the following medical societies: American Academy of Dermatology

Disclosure: Nothing to disclose.

Additional Contributors

James W Patterson, MD Professor of Pathology and Dermatology, Director of Dermatopathology, University of Virginia Medical Center

James W Patterson, MD is a member of the following medical societies: American Academy of Dermatology, American College of Physicians, American Society of Dermatopathology, Royal Society of Medicine, Society for Investigative Dermatology, United States and Canadian Academy of Pathology

Disclosure: Nothing to disclose.

Acknowledgements

Joseph C English III, MD Clinical Vice-Chairman for Quality and Innovation, Professor of Dermatology, Department of Dermatology, University of Pittsburgh School of Medicine

Joseph C English III, MD is a member of the following medical societies: American Academy of Dermatology and American Medical Association

Disclosure: Nothing to disclose.