Fossa keratosis is currently considered to be a bacterial infectious dermatosis, the main causative organisms being gram-positive cocci and filamentous bacteria, with Corynebacterium and Streptomyces being the most likely, occurring mainly at and below the metatarsal area, with sweaty soles of the feet accompanied by a distinct odour (foul smell) and increased stickiness of the skin being the most typical symptoms of fossa keratosis.
The characteristic symptom of keratosis pilaris is the appearance of keratosis pilaris in the lower part of the feet and toes, surrounded by a ring of black grooves, which resemble craters in general, either as individual pits or fused together in an irregular pattern.
The disease is a bacterial infection and is not contagious. However, prompt treatment, attention to personal hygiene and keeping the foot environment clean and dry will facilitate recovery from the disease.