Pitted keratolysis

Pitted keratolysis
Other namesKeratolysis plantare sulcatum, Keratoma plantare sulcatum, Ringed keratolysis, and sweaty sock syndrome
Right foot affected with pitted keratolysis
SpecialtyDermatology 
SymptomsLarge, crater-like holes on the foot
CausesCorynebacterium species and other bacteria
Differential diagnosisAthlete's foot (Tinea pedis), erythrasma, hyperhidrosis
PreventionKeeping the feet dry, antiperspirants
TreatmentAntibiotics

Pitted keratolysis (also known as keratolysis plantare sulcatum, keratoma plantare sulcatum, and ringed keratolysis) is a bacterial skin infection of the foot. The infection is characterized by craterlike pits on the sole of the feet and toes, particularly weight-bearing areas.

The infection is caused by Kytococcus sedentarius. Excessive sweating of the feet and use of occlusive footwear provide an environment in which these bacteria thrive and therefore increase the risk of developing pitted keratolysis.

The condition is fairly common, especially in the military where wet shoes/boots are worn for extended periods of time without removing/cleaning. Skin biopsy specimens are not usually utilized, as the diagnosis of pitted keratolysis is often made by visual examination and recognition of the characteristic odor. Wood's lamp examination results are inconsistent. Treatment of pitted keratolysis requires the application of antibiotics to the skin such as benzoyl peroxide, clindamycin, erythromycin, fusidic acid, or mupirocin. Prevention efforts aim to keep the feet dry by using moisture-wicking shoes and socks as well as antiperspirants.