Scalp ringworm (tinea capitis): causes and treatment

Tinea capitis is a fungal infection that lives in and around the hair shaft. The same group of fungi, called dermatophytes, also cause ringworm of the body. They are found on people, animals and in the environment. The British Association of Dermatologists names Trichophyton and Microsporum as the common species.

The scalp matters because hair holds the fungus. The infection involves the hair as well as the skin, which is likely why the NHS says scalp ringworm usually needs tablets taken by mouth and a medicated shampoo rather than the cream or spray that works for a patch on the arm or leg.

The condition can happen at any age but is most often seen in children. In adults it is less usual, and it may be mistaken for other scalp problems for some time.

The appearance varies a lot. The BAD leaflet says it can resemble dandruff, alopecia, eczema or psoriasis of the scalp. Typical symptoms are itching, redness and dryness. Sometimes bald patches appear because infected hairs are brittle and break easily.

In more severe cases, the BAD describes pustules (white or yellow-headed spots), yellow crusts and matted hair. Very rarely a painful, boggy swelling filled with pus and overlying hair loss, called a kerion, develops. People with these changes may have a fever or swollen, painful glands in the neck.

NHS notes also mention that ringworm on the face or scalp may cause patchy hair loss, and that the rash may look less ring-shaped on the scalp than elsewhere.

• Patchy hair loss with broken hairs close to the scalp.

• Dry, scaly, itchy skin that looks like stubborn dandruff.

• Pustules, crusting or matted hair in more inflamed infections.

• An "id reaction": the BAD says the body can sometimes react with an itchy rash elsewhere, such as the ears or palms and soles, and it can appear when treatment is started.

The BAD says tinea capitis is contagious. It passes through close contact with an infected person, or by sharing combs, hairbrushes, hats, clothing, towels, beds and other furniture. Cats, dogs, horses and farm animals can also pass it on.

The fungus can live for long periods in the environment, so infection can occur months after contact. This also explains why brushes and hair accessories matter: the BAD suggests cleaning them with simple bleach or replacing them.

Because it spreads easily in groups, a case in a child often leads to questions about siblings and classmates. The BAD advises informing the child's teacher, the parents of classmates and other playmates so that children can be examined and treated if needed.

A doctor will suspect scalp ringworm when a scaly scalp occurs together with hair loss, especially in a child. The BAD says a dermatoscope, a hand-held magnifying light, may help the doctor decide what is affecting the scalp.

Confirmation comes from the laboratory. Skin scales are taken from the scalp, or hairs are plucked from affected areas, then examined under a microscope and cultured. The BAD notes that fungus grows slowly, so culture results can take up to 6 weeks.

Because of that delay, a doctor who is strongly suspicious may start oral treatment straight away. The BAD explains that the medicine can be changed if the results show a different organism, which is why the type of fungus matters.

The BAD says scalp ringworm needs oral antifungal medicine, available only on prescription, plus a medicated antifungal shampoo bought over the counter. The shampoo reduces spread to other people, and it is used twice weekly. The examples given are 2% ketoconazole or 1% selenium sulphide.

Terbinafine is described as very effective and usually the first choice. A 4-week course is needed. The leaflet is open that it is not licensed in children because the manufacturer has not applied for a licence, although it is very commonly prescribed in children.

Griseofulvin is the only licensed oral antifungal for children and needs a 6 to 8 week course. The tablets can be crushed in a little water if swallowing is difficult. Itraconazole and fluconazole are other options.

The BAD advises not to share combs, hairbrushes, hats, towels, pillowcases or helmets, and to wash bedding, towels and hats at 60 degrees. It also advises avoiding the hairdresser or barber until the infection is clear, and asking that combs, scissors and clippers are sterilised between clients.

Other household members and pets should be examined. The BAD says some families are advised to use the medicated shampoo twice a week for four weeks whether or not infection is proven, to reduce the chance of passing it around.

Follow-up testing may be arranged. Further hair samples may be sent after treatment to check it has worked, and a second course may be needed if fungus is still found.

The BAD states that tinea capitis can be cured if treated adequately, as it is an infection. Re-infection is the main nuisance, which is why checking close contacts is part of management.

Left untreated, it could cause permanent scarring and hair loss, and the inflamed skin can pick up a secondary bacterial infection. If a doctor suspects this, a course of antibiotics may be added.

Early treatment is therefore worthwhile. A kerion, the severe inflamed pattern described earlier, is a reason to seek prompt medical review.