History

Patient with pitted keratolysis may report malodor, hyperhidrosis, sliminess, and, occasionally, soreness or itching associated with the pits^[31]; however, the pits normally are asymptomatic. Patients with primary hyperhidrosis have been shown to have a significant increase in pitted keratolysis compared with controls.^[32]

The etiology of the tenderness in symptomatic cases of pitted keratolysis is unknown. In addition to pits, erythematous-to-violaceous macules to plaquelike lesions may be present.^[29]In military personnel, whose long-term occlusive boot wearing exacerbates disease, lesions often become denuded, leading to foot pain and disability.^[33]The palms of the hand also have been reported to be involved in some patients with pitted keratolysis of the feet.^[34]Of the paddy field workers, 1.5% were diagnosed with palmar lesions in addition to foot lesions.^[25]With hand involvement, a collarette forms around the keratolysis, rather than pits.

A triad of concurrent corynebacterial diseases (ie, erythrasma, trichomycosis axillaris, and pitted keratolysis) has been reported.^[35]In a 2008 study, 108 of 842 South Korean male soldiers were diagnosed with pitted keratolysis, of which 13 (13%) of 108 had the triad.^[27]Clinicians making a diagnosis of pitted keratolysis need to examine the patient for evidence of other corynebacterial infections.

Physical Examination

The primary lesions of pitted keratolysis are pits in the stratum corneum ranging from 0.5-7 mm, with some development of confluence, irregular erosions, or sulci (see the images below).

A large plaque-like lesion of Pitted keratolysis on the large toe.

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Pitted keratolysis with hyperkeratosis on the heel.

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Classic pits of pitted keratolysis on the plantar aspect of the phalanges.

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Pitted keratolysis forming sulci on the heel.

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A variant of markedly enlarged lesions, called crateriform pitted keratolysis, also has been described.^[36]This affects the entire width of the plantar surface of the foot underlying the metatarsophalangeal joints. The pits are rarely seen on non–pressure-bearing areas of the plantar surface, but this has been reported in the literature.^[37]

Differential Diagnoses

de Almeida HL Jr, Siqueira RN, Meireles Rda S, Rampon G, de Castro LA, Silva RM. Pitted keratolysis. An Bras Dermatol. 2016 Jan-Feb. 91 (1):106-8. [QxMD MEDLINE Link].
Bunyaratavej S, Leeyaphan C, Chanyachailert P, Pattanaprichakul P, Ongsri P, Kulthanan K. Clinical manifestations, risk factors, and quality of life in pitted keratolysis: A cross-sectional study in cadets. Br J Dermatol. 2018 Jun 28. [QxMD MEDLINE Link].
Zaias N, Taplin D, Rebell G. Pitted keratolysis. Arch Dermatol. 1965 Aug. 92(2):151-4. [QxMD MEDLINE Link].
Rubel LR. Pitted keratolysis and Dermatophilus congolensis. Arch Dermatol. 1972 Apr. 105(4):584-6. [QxMD MEDLINE Link].
Nordstrom KM, McGinley KJ, Cappiello L, Zechman JM, Leyden JJ. Pitted keratolysis. The role of Micrococcus sedentarius. Arch Dermatol. 1987 Oct. 123(10):1320-5. [QxMD MEDLINE Link].
Woodgyer AJ, Baxter M, Rush-Munro FM, Brown J, Kaplan W. Isolation of Dermatophilus congolensis from two New Zealand cases of pitted keratolysis. Australas J Dermatol. 1985 Apr. 26(1):29-35. [QxMD MEDLINE Link].
Valente NY, Ribeiro Costa A, Pessoa Mendes J. [Pitted keratolysis. Presentation of 2 cases with culture of lesions positive for bacteria of the genus Corynebacterium]. Med Cutan Ibero Lat Am. 1983. 11(1):61-4. [QxMD MEDLINE Link].
Longshaw CM, Wright JD, Farrell AM, Holland KT. Kytococcus sedentarius, the organism associated with pitted keratolysis, produces two keratin-degrading enzymes. J Appl Microbiol. 2002. 93(5):810-6. [QxMD MEDLINE Link].
Holland KT, Marshall J, Taylor D. The effect of dilution rate and pH on biomass and proteinase production by Micrococcus sedentarius grown in continuous culture. J Appl Bacteriol. 1992 May. 72(5):429-34. [QxMD MEDLINE Link].
Hanel H, Kalisch J, Keil M, Marsch WC, Buslau M. Quantification of keratinolytic activity from Dermatophilus congolensis. Med Microbiol Immunol. 1991. 180(1):45-51. [QxMD MEDLINE Link].
Valipe SR, Nadeau JA, Annamali T, Venkitanarayanan K, Hoagland T. In vitro antimicrobial properties of caprylic acid, monocaprylin, and sodium caprylate against Dermatophilus congolensis. Am J Vet Res. 2011 Mar. 72(3):331-5. [QxMD MEDLINE Link].
Amor A, Enríquez A, Corcuera MT, Toro C, Herrero D, Baquero M. Is infection by Dermatophilus congolensis underdiagnosed?. J Clin Microbiol. 2011 Jan. 49(1):449-51. [QxMD MEDLINE Link]. [Full Text].
Nordstrom KM, McGinley KJ, Capiello L, Leyden JJ. The etiology of malador associated with pitted keratolysis. Journal of Investigative Dermatology. July/1986. 87:159.
Ara K, Hama M, Akiba S, et al. Foot odor due to microbial metabolism and its control. Can J Microbiol. 2006 Apr. 52(4):357-64. [QxMD MEDLINE Link].
Wohlrab J, Rohrbach D, Marsch WC. Keratolysis sulcata (pitted keratolysis): clinical symptoms with different histological correlates. Br J Dermatol. 2000 Dec. 143(6):1348-9. [QxMD MEDLINE Link].
Adamczyk K, Garncarczyk A, Antończak P, Wcisło-Dziadecka D. The foot microbiome. J Cosmet Dermatol. 2020 May. 19 (5):1039-1043. [QxMD MEDLINE Link].
Myers TM, Bigler CJ, Maurer MB, Gaither ME, Taylor WM. Tolio: Foot Rot in Grand Canyon River Runners. Wilderness Environ Med. 2020 Mar. 31 (1):82-86. [QxMD MEDLINE Link].
Hsu AR, Hsu JW. Topical review: skin infections in the foot and ankle patient. Foot Ankle Int. 2012 Jul. 33(7):612-9. [QxMD MEDLINE Link].
De Luca JF, Adams BB, Yosipovitch G. Skin manifestations of athletes competing in the summer olympics: what a sports medicine physician should know. Sports Med. 2012 May 1. 42(5):399-413. [QxMD MEDLINE Link].
Stratigos AJ, Stern R, Gonzalez E, Johnson RA, O'Connell J, Dover JS. Prevalence of skin disease in a cohort of shelter-based homeless men. J Am Acad Dermatol. 1999 Aug. 41(2 Pt 1):197-202. [QxMD MEDLINE Link].
Eun HC, Park HB, Chun YH. Occupational pitted keratolysis. Contact Dermatitis. 1985 Feb. 12(2):122. [QxMD MEDLINE Link].
Tuncel AA, Erbagci Z. Prevalence of skin diseases among male adolescent and post-adolescent boarding school students in Turkey. J Dermatol. 2005 Jul. 32(7):557-64. [QxMD MEDLINE Link].
Blaise G, Nikkels AF, Hermanns-Le T, Nikkels-Tassoudji N, Pierard GE. Corynebacterium-associated skin infections. Int J Dermatol. 2008 Sep. 47(9):884-90. [QxMD MEDLINE Link].
Nnoruka EN. Current epidemiology of atopic dermatitis in south-eastern Nigeria. Int J Dermatol. 2004 Oct. 43(10):739-44. [QxMD MEDLINE Link].
Shenoi SD, Davis SV, Rao S, Rao G, Nair S. Dermatoses among paddy field workers--a descriptive, cross-sectional pilot study. Indian J Dermatol Venereol Leprol. 2005 Jul-Aug. 71(4):254-8. [QxMD MEDLINE Link].
Gill KA Jr, Buckels LJ. Pitted keratolysis. Arch Dermatol. 1968 Jul. 98(1):7-11. [QxMD MEDLINE Link].
Rho NK, Kim BJ. A corynebacterial triad: Prevalence of erythrasma and trichomycosis axillaris in soldiers with pitted keratolysis. J Am Acad Dermatol. 2008 Feb. 58(2 Suppl):S57-8. [QxMD MEDLINE Link].
Lamberg SI. Symptomatic pitted keratolysis. Arch Dermatol. 1969 Jul. 100(1):10-1. [QxMD MEDLINE Link].
Shah AS, Kamino H, Prose NS. Painful, plaque-like, pitted keratolysis occurring in childhood. Pediatr Dermatol. 1992 Sep. 9(3):251-4. [QxMD MEDLINE Link].
Dogan B. Dermatological manifestations in hepatitis B surface antigen carriers in east region of Turkey. J Eur Acad Dermatol Venereol. 2005 May. 19(3):323-5. [QxMD MEDLINE Link].
Takama H, Tamada Y, Yano K, Nitta Y, Ikeya T. Pitted keratolysis: clinical manifestations in 53 cases. Br J Dermatol. 1997 Aug. 137(2):282-5. [QxMD MEDLINE Link].
Walling HW. Primary hyperhidrosis increases the risk of cutaneous infection: a case-control study of 387 patients. J Am Acad Dermatol. 2009 Aug. 61(2):242-6. [QxMD MEDLINE Link].
Schissel DJ, Aydelotte J, Keller R. Road rash with a rotten odor. Mil Med. 1999 Jan. 164(1):65-7. [QxMD MEDLINE Link].
Zaias N. Pitted and ringed keratolysis. A review and update. J Am Acad Dermatol. 1982 Dec. 7(6):787-91. [QxMD MEDLINE Link].
Shelley WB, Shelley ED. Coexistent erythrasma, trichomycosis axillaris, and pitted keratolysis: an overlooked corynebacterial triad?. J Am Acad Dermatol. 1982 Dec. 7(6):752-7. [QxMD MEDLINE Link].
Sehgal VN, Ramesh V. Crateriform depression--an unusual clinical expression of pitted keratolysis. Dermatologica. 1983. 166(4):209-11. [QxMD MEDLINE Link].
Takama H, Tamada Y, Yokochi K, Ikeya T. Pitted keratolysis: a discussion of two cases in non-weight-bearing areas. Acta Derm Venereol. 1998 May. 78(3):225-6. [QxMD MEDLINE Link].
Vlahovic TC, Dunn SP, Kemp K. The use of a clindamycin 1%-benzoyl peroxide 5% topical gel in the treatment of pitted keratolysis: a novel therapy. Adv Skin Wound Care. 2009 Dec. 22(12):564-6. [QxMD MEDLINE Link].
Singh G, Naik CL. Pitted keratolysis. Indian J Dermatol Venereol Leprol. 2005 May-Jun. 71(3):213-5. [QxMD MEDLINE Link].
de Almeida HL Jr, de Castro LA, Rocha NE, Abrantes VL. Ultrastructure of pitted keratolysis. Int J Dermatol. 2000 Sep. 39(9):698-701. [QxMD MEDLINE Link].
Gardner TL, Elston DM. A foot rash with a foul odor. Phys Sport Med. 1998. 26:104-6.
Burkhart CG. Pitted keratolysis: a new form of treatment. Arch Dermatol. 1980 Oct. 116(10):1104. [QxMD MEDLINE Link].
Papaparaskevas J, Stathi A, Alexandrou-Athanassoulis H, Charisiadou A, Petropoulou N, Tsakris A, et al. Pitted keratolysis in an adolescent, diagnosed using conventional and molecular microbiology and successfully treated with fusidic acid. Eur J Dermatol. 2014 Jul-Aug. 24(4):499-500. [QxMD MEDLINE Link].
Vazquez-Lopez F, Perez-Oliva N. Mupirocine ointment for symptomatic pitted keratolysis. Infection. 1996 Jan-Feb. 24(1):55. [QxMD MEDLINE Link].
Greywal T, Cohen PR. Pitted keratolysis: successful management with mupirocin 2% ointment monotherapy. Dermatol Online J. 2015 Aug 15. 21 (8):[QxMD MEDLINE Link].
van der Snoek EM, Ekkelenkamp MB, Suykerbuyk JC. Pitted keratolysis; physicians' treatment and their perceptions in Dutch army personnel. J Eur Acad Dermatol Venereol. 2012 Aug 7. [QxMD MEDLINE Link].
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Leeyaphan C, Limphoka P, Kiratiwongwan R, Ongsri P, Bunyaratavej S. Randomized, controlled trial testing the effectiveness and safety of 2.5% and 5% benzoyl peroxide for the treatment of pitted keratolysis. J Dermatolog Treat. 2020 Jan 3. 1-4. [QxMD MEDLINE Link].
Tamura BM, Cuce LC, Souza RL, Levites J. Plantar hyperhidrosis and pitted keratolysis treated with botulinum toxin injection. Dermatol Surg. 2004 Dec. 30(12 Pt 2):1510-4. [QxMD MEDLINE Link].

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.