Curriculum · ENT, Ophthalmology, and Dermatology
Tinea pedis
What it is
Athlete's foot is also known as tinea pedis. It is usually caused by fungi in the genus Trichophyton, and in the interdigital type the most common organism is named: Trichophyton rubrum.
It is one of the dermatophytoses, also known as ringworm or tinea, a superficial fungal infection caused by dermatophytes: Trichophyton, Microsporum and Epidermophyton. The infection is limited to the stratum corneum, hair and nail, and it is that limit which makes a topical agent enough for skin disease and not enough for hair and nail.
Ringworm is named for the site it involves: tinea capitis on the scalp, tinea faciei on the face excluding beard and moustache, tinea barbae on the beard and moustache, tinea cruris in the groin, tinea corporis on the trunk and extremities, tinea pedis on the soles or toes, tinea unguim on the nail, and tinea manum on the palm.
How it presents
It typically gives scaling, flaking and itching between the toes, and the lesion between the toes may look whitish. The case put on it is a 60 year old male, known to have DM, with a whitish lesion between the toes.
Interdigital tinea pedis shows scaling and maceration between the toes, especially the 4th web space, and that pair, scaling plus maceration in the 4th web space, is given as the classic clue.
The general features of tinea are an annular plaque with central clearing and a scaly, itchy border. Its common sites are moist areas, feet, groin and scalp, and shared surfaces such as showers and gyms; transmission is person-to-person, from animals, and from contaminated surfaces.