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pitted keratolysis
Etiology:
1) Corynebacterium species (major cause)
2) Kytococcus sedentarius (formerly Micrococcus sedentarius)
3) Dermtaophilus congolensis
4) Actinomyces
5) Streptomyces
6) hyperhidrosis of the feet predisposes
- warmth, mosture, occlusion are risk factors
Epidemiology:
1) affects mostly young adults
2) affects males >> females
Pathology:
- thickening of plantar fascia [5]
Clinical manifestations:
1) manifests as scale & pitting of the skin surface
2) pits in stratum corneum of plantar foot 1-8 mm in diameter
3) pits may be discrete, but more often become confluent forming large areas of eroded stratum corneum
4) involved areas are white when stratum corneum is fully hydrated
5) symmetric or asymmetric involvement of both feet
6) distribution:
a) toe webs, balls or heel of foot in contact with shoe
b) lesions on pressure-bearing locations
7) generally asymptomatic, but may be associated with itching, burning or tenderness
8) foot odor (malodorous)
9) hyperhidrosis
* images [2]
Laboratory:
1) no hyphae in 10% KOH preparations from skin scrapings
2) Wood's lamp: negative for coral-red fluorescence (erythrasma)
3) culture (rule out Staphylococcus aureus, group A streptococcus, Pseudomonas aeruginosa)
Differential diagnosis:
1) tinea pedis
2) Candida intertrigo
3) erythrasma
- red-brown plaques in the groin, crural folds, gluteal folds, axillae,
- less commonly in the interdigital or inframammary regions
- skin often has a thin, wrinkled appearance similar to cigarette paper
- soft coral red fluorescence under Woods lamp
4) gram-negative bacillus web infection
5) plantar wart
- exophytic papules on the soles of the feet
- hyperkeratotic debris often covers the tops of the lesions
- after scraping lesion surface, black or red dots (thrombosed capillaries) become visible
Management:
1) prophylaxis
- wash with lather from benzoyl peroxide soap bar
- antiperspirants (AlCl3)
2) treatment
- benzoyl peroxide: apply daily
- topical erythromycin: apply daily
Related
nail pitting
General
keratolysis
bacterial infection
skin infection
References
- Color Atlas & Synopsis of Clinical Dermatology, Common
& Serious Diseases, 3rd ed, Fitzpatrick et al, McGraw Hill, NY,
1997, pg 620-21
- Fromm LJ, Elston DM (images)
Medscape: Pitted Keratolysis
http://emedicine.medscape.com/article/1053078-overview
- DermNet NZ. Pitted keratolysis (images)
http://www.dermnetnz.org/bacterial/pitted-keratolysis.html
- Pranteda G, Carlesimo M, Pranteda G et al
Pitted keratolysis, erythromycin, and hyperhidrosis.
Dermatol Ther. 2014 Mar-Apr;27(2):101-4.
PMID: 2470326
- Medical Knowledge Self Assessment Program (MKSAP) 18,
American College of Physicians, Philadelphia 2018
- Leung AK, Barankin B.
Pitted Keratolysis.
J Pediatr. 2015 Nov;167(5):1165.
PMID: 26316369