Case Study : Dermatology
59. Pitted Keratolysis
59. Malodorous itchy feet
A 16-year-old boy presented to his family physician (FP) with malodorous feet and some itching between his toes.
He was somewhat embarrassed to take off his shoes, but the FP convinced him that his feet must be examined to make the diagnosis and provide appropriate treatment.
The boy removed his shoes and the FP examined his feet while wearing gloves.
The boy played soccer on his high school team and was in otherwise good health
Diagnosis: Pitted Keratolysis
This patient was suffering from pitted keratolysis and interdigital tinea pedis.
Pitted keratolysis is caused by the bacterium Kytococcus sedentarius.
Like tinea pedis, moist and sweaty feet provide a great environment for growth of this organism.
The patient admitted to having sweaty feet—especially while playing soccer for hours.
He also didn’t use shower shoes in the gym shower.
In pitted keratolysis, the bacteria live on the dead cells of the stratum corneum of the sole and form visible pits.
In interdigital tinea pedis, the skin between the toes is white in appearance.
The FP recommended that the patient wear shower shoes and change his socks during the day if they become sweaty.
He also prescribed topical 2% erythromycin solution to apply twice daily to the area with visible pits.
In addition, the FP recommended that the patient buy over-the-counter topical terbinafine cream and apply it between the toes once or twice daily—especially after drying his feet well after a shower.
A month later, both infections were clear.
Photos and text for Photo Rounds Friday courtesy of Richard P. Usatine, MD. This case was adapted from: Usatine R, Reppa R. Tinea pedis. In: Usatine R, Smith M, Mayeaux EJ, et al, eds. Color Atlas of Family Medicine. 2nd ed. New York, NY: McGraw-Hill; 2013:799-804.
In the ROI, 2% erythromycin + isotretinoid gel is available in Ireland as Isotrex
and 4% erythromycin + 1,2% zinc acetate topical solution is available in Irelandas Zineryt
Terbinafine cream is available in Ireland as Lamisil
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