The results are unsightly and common infections of the skin, hair, and nails known popularly as ringworm and more precisely as tinea . The clinical appearance varies according to the site. On the skin, there is an erythematous, sometimes scaly patch. In the hair, broken shafts are common, sometimes associated with alopecia. On the nails, there is hyperkeratosis with dystrophy.
Microbiologists classify dermatophytes into three genera.
The organisms vary in the site of infections and by geography. In addition to affecting humans and animals, they may live in the soil. In general, T. tonsurans and T. rubrum infections are increasing while M. canis and M. audouinii are declining. Abstract quote Dermatophyte infections of the penis and scrotum are relatively rare compared with those involving the groin. Four cases of penile tinea due to Trichophyton rubrum are described.