The dermatophyte infections are caused by fungi (genus microsporum, trichophyton and epidermophyton) which thrive on non-viable keratinised tissue of the skin (stratum, comeum hair nails). Sources of infection include other persons, animals such as puppies or kittens and more rarely the soil.

Nomenclature is “tinea” followed by the Latin name of the appropriate part.

Tinea pedis (athletes foot) Scaling or maceration between toes particularly the fourth interspace. Causative organism is T. rubrum and/or T. interdigitalae. Hot humid weather and occlusive footwear are predisposing factors.

Tinea cruris An erythematous and scaly rash with distinct margin extending from groin to upper thighs or scrotum. Itching may be severe. Common in males.

Tinea corporis (body ringworm) Characteristically annular plaque with raised edge and central clearing scaling and itching variable.

Tinea capitis (scalp ringworm) Mainly disease of children and spontaneous recovery at puberty normal. Scaling, itching, loss of hair is common - “Mashillingi”. Scarring, alopecia may result.

Tinea anguum Involves the nails and presents with nail discolouration and subungual hyperkeratosis (friable debris)

Investigations

• Direct microscopy of skin scale in 20% potassium hydroxide mounted on a slide to demonstrate hyphae.

Management

• For wet lesions (in skin folds) apply gentian violet 0.5% paint daily and when the lesions dry apply Whitfield's ointment BD until 1 week after lesions have healed

• Griseofulvin 500 mg daily with food as single dose for 1 month (in children 10 mg/kg).