This 36-year-old man had a history of severe hyperhidrosis affecting his hands and feet. He was otherwise well and taking no medication. The hyperhidrosis was causing maceration of his plantar skin. He had tried talc and topical antiperspirants, with no benefit. Examination revealed severe extensive pitted keratolysis (PK) on a background of moist, macerated skin. The PK did not concern him, but he was referred for a course of botulinum toxin injections to reduce the hyperhidrosis.
PK is a common superficial bacterial skin infection characterised by typical multifocal, discrete, crateriform pitting and superficial erosions. PK lesions are pits in the stratum corneum of 1mm to 7mm diameter, which can become confluent to form craters, sulci or irregular erosions. PK typically affects the pressure-bearing surfaces of the feet, including the toes, ball of the foot and heel. It rarely affects non pressure-bearing areas.