Ringworm of the scalp (tinea capitis)
Reviewed by Dr Victoria Lewis, consultant dermatologist
What is ringworm of the scalp?
|One or more sections of the scalp will show hair loss or give a stubbly appearance.|
Ringworm of the scalp is a type of fungal infection. The most common species of fungi affecting humans are Microsporum canis and Tricophyton verrucosum.
The majority of UK cases are due to another type of fungus, namely, Tricophyton tonsurans. The medical term for ringworm of the scalp is tinea capitis.
How is it caught?
In most cases, the disease is transferred by way of contact with animals (eg dogs, cats, cows, hamsters and guinea pigs).
Most mammals have a skin fungus with which they live in peaceful coexistence, without any symptoms for the animal, but the fungus can be transferred to humans.
Ringworm is most common among farming populations whose lifestyle involves frequent contact with animals. Children are particularly at risk; between children the infection can be highly contagious.
What are the signs of ringworm of the scalp?
There are two common types of symptoms.
One or more sections of the scalp will show hair loss or give a stubbly appearance. The skin will be slightly scaly but with little or no irritation. In addition to these symptoms, ringworm may be present on the face or other parts of the body.
Alternatively, a 6 to 9cm wide lesion will appear that may develop into a large rash.
In severe cases, a kerion (a swollen mass discharging pus) will appear on the scalp. The kerion may become inflamed and fill with fluid or pus, and may also be quite painful.
Severe alopecia (baldness) may develop and at this stage the scalp will often become infected further with Staphylococci bacteria. The lymph nodes of the neck can also become swollen and tender. In rare cases, there may also be a fever.
Who is at special risk?
Children in close contact with animals.
It is difficult to avoid the fungi that cause ringworm as they are everywhere in our surroundings.
However, a good preventive measure is to minimise direct contact with animals showing symptoms of ringworm, such as scaly, patchy skin.
How does the doctor diagnose ringworm?
Many other skin diseases can have similar symptoms but require very different treatment. It is therefore important for the doctor to perform several tests and not to rely only on a visual diagnosis.
A scraping of the fungi can be taken for microscopic checks and cultivation to identify it.
Some fungi will appear fluorescent (glow in the dark) under ultraviolet light. This could be done by a GP or by a dermatologist (a skin specialist).
Treatment should be started as soon as possible to avoid the fungal infection spreading further and to avoid infection of other healthy people.
If a kerion forms, bacteria build up in the hair follicles and cause tumour-like swellings that ooze pus, which can lead to permanent baldness in some areas of the scalp.
How is ringworm affecting the scalp treated?
If a large kerion has formed, the antifungal treatment may be supplemented with corticosteroids for a short period of time to reduce swelling and inflammation.
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Last updated 05.06.2014