Ringworm of the scalp

Tinea Capitis: a contagious disease caused by the invasion of the scalp/hair by a fungus.

An infected scalp will present as:

i) Scaly patches with hair loss or broken hairshafts. ii) Extensive lesions which may develop into a rash. iii) Kerion - a swollen mass discharging pus onto the scalp. May be painful. Alopecia (baldness) may develop. Staphylococci (bacteria) may co-exist. The lymph nodes of the neck can also become swollen and tender. Fever is possible though rare.

Caution: Symptoms of hair loss (when lesions are circumscribed) may be confused with alopecia areata.

Fungi are either:

i) Ectothrix. These fungi invade hairshafts beyond the skin level, resulting in breakage at skin level and the characteristic 'black dots' symptom. ii) Endothrix. These fungi invade the pilo-sebaceous follicles causing serious inflammatory skin conditions + hair losses/breakage.

Classification of Fungi

Anthropophilic fungi (humans being the natural hosts):

i) Microsporon audouini may be inculcated in epidemics with children (transmitted by shared hats combs brushes towels and through contaminated barber's instruments etc). Symptoms may include localised erythema in circumscribed areas (maximum diameter 5 cm) which soon fades to leave superficial scaling with broken brittle twisted grey-white hair stumps measuring approx. 3 mm above the scalp. Occasionally kerion results. Kerion may be caused by a build-up of either large or small spored ringworm bacteria in the hair follicles. This presents as purple/red raised boggy swellings discharging pus. Any consequential baldness is usually temporary.

ii) Trichophyton tonsurans, T. sulphureum, T. violaceum -(endothrix trichophyta) Each presents as black dots within the skin - caused by hairshafts broken at or below skin level. Early symptoms may mimic pityriasis simplex ('dandruff') but a more vigorous inflammatory reaction may produce follicular pustulation and possibly Kerion. In this infection is most commonly due to trichophyton tonsurans.

Zoophilic fungi (other animals being the natural hosts).

The fungus can be transferred to humans from animal hosts e.g. cats (kittens especially), dogs, cows etc - These animals habitually carry the fungus but are not adversely affected by it. This explains why it is most commonly seen among farming populations. Children are particularly at risk as the disease is highly contagious. Farm workers are also vulnerable. The disease usually presents as actively inflammatory lesions. These infections are commonly due to M. canis, or T. verrucosum. The early symptoms also include circumscribed scaly patches with lustreless broken twisted hair stumps. The infection may lead to severe inflammatory changes presenting as erythematous swollen crusty patches. Kerion may follow.

Geophilic fungi
M. gypseum contracted by humans from the soil.

Things to do:
Avoid direct contact with animals showing symptoms e.g. scaly, patchy skin.

Treatment may include:
i) a fungicidal or antibiotic cream for local application and aural medication.
ii) Kerion will require corticosteroid therapy.