Tinea Capitis (Scalp Ringworm)

What causes tinea capitis

Tinea capitis is caused by dermatophytes, fungi that live on keratin, the protein in skin, hair and nails. The species involved depends on where you live:

• Trichophyton tonsurans causes most cases in the US and UK. It spreads person to person.
• Microsporum canis comes from cats and dogs.
• Other Trichophyton species are common in Africa and the Middle East and in children who have recently traveled there.

The fungus can invade the inside of the hair shaft (endothrix) or coat its surface (ectothrix). Infected hairs become brittle and break off.

How it spreads

• direct head-to-head contact, common among siblings and classmates
• sharing combs, brushes, hats, hair accessories, pillows and towels
• contact with infected pets
• spores can survive on objects for months

Adults in the household can carry the fungus on their scalp without symptoms and keep reinfecting children.

Types and symptoms

Other common signs:

• itching
• swollen lymph nodes at the back of the neck or behind the ears
• an itchy "id reaction": a widespread rash of small bumps on the body, which is an immune reaction rather than spread of the fungus. It can appear after treatment starts and is not a reason to stop treatment

A kerion can be mistaken for a bacterial abscess. It should not be cut open, as it is not a pus collection that drains, and it improves with antifungal treatment. Untreated or severe kerions can leave permanent scarring and hair loss.

Conditions that look similar

• Seborrheic dermatitis and dandruff: greasy yellow scales without broken hairs. Uncommon in children between infancy and puberty, so "dandruff" in a child should prompt a fungal test.
• Alopecia areata: smooth, completely bald patches with no scaling.
• Psoriasis and atopic dermatitis of the scalp.
• Traction alopecia from tight hairstyles.
• Bacterial folliculitis or impetigo.

Diagnosis

• Examination of the scalp, sometimes using a dermatoscope.
• Scalp scraping and plucked hairs, or a sample taken by brushing the scalp with a sterile toothbrush or swab, are examined under a microscope with potassium hydroxide (KOH) and sent for fungal culture. Culture takes 2 to 4 weeks but identifies the species, which helps choose the medicine.
• Wood's lamp: an ultraviolet light makes hairs infected by Microsporum glow green. T. tonsurans does not glow, so a negative result does not rule out infection.

Doctors often start treatment while waiting for culture results when the diagnosis is clear.

Tinea capitis treatment

Oral antifungal medicine

Creams cannot reach the fungus inside the hair follicle, so oral treatment is required.

• Griseofulvin: the long-established treatment, especially for Microsporum. It is usually taken for 6 to 12 weeks, best absorbed with fatty food such as milk or ice cream.
• Terbinafine: often preferred for Trichophyton infections because courses are shorter, typically 4 to 6 weeks. It comes as tablets or granules.
• Itraconazole or fluconazole are alternatives in some cases.

Your doctor will choose the medicine and dose based on the child's weight and the fungus. Continue for the full course, even after the scalp looks better. Treatment is usually continued until a follow-up check or culture confirms cure.

Side effects are usually mild, such as stomach upset, headache or rash. Rarely, these medicines affect the liver. Report yellow skin, dark urine or severe tiredness at once.

Antifungal shampoo

Selenium sulfide 1% to 2.5% or ketoconazole 2% shampoo, used two to three times a week, reduces spores on the scalp and the risk of spread. It does not cure the infection on its own. Household members can use it too.

Kerion

Kerions are treated with oral antifungals. A doctor may add a short course of oral steroids for severe inflammation, or antibiotics if a bacterial infection is also present.

Preventing spread

• Do not share combs, brushes, hats, towels or pillows.
• Wash or replace brushes and combs, and wash bedding, hats and towels in hot water.
• Check other children and adults in the home, and treat anyone affected. Carriers without symptoms may be advised to use antifungal shampoo.
• Have pets with patchy hair loss checked by a vet.
• Children can usually return to school once oral treatment and antifungal shampoo have started. Shaving the head and keeping children home for weeks are not necessary.

Outlook

With a full course of oral treatment, most children are cured and hair grows back over several months. Treatment failure is usually due to stopping early, reinfection from family members or pets, or a less sensitive fungus. Severe kerions or favus can leave scarred, permanent bald patches.

For fungal infections on the body or the hair more generally, see ringworm and hair fungus.

Frequently asked questions

Is tinea capitis contagious?

Yes. Tinea capitis spreads through direct contact and by sharing combs, brushes, hats, pillows and towels. Some types spread from cats and dogs. Children are less contagious once they start oral treatment and antifungal shampoo, and can usually return to school.

Can tinea capitis be treated with cream?

No. Antifungal creams do not penetrate the hair follicles where the fungus lives. Tinea capitis needs antifungal medicine taken by mouth, such as griseofulvin or terbinafine, for several weeks. Antifungal shampoo is added to reduce spread but does not cure it alone.

How long does tinea capitis take to go away?

Treatment usually lasts 4 to 12 weeks, depending on the medicine and the fungus. Scaling and itching often improve within a few weeks, but hair regrowth takes several months. Finishing the full course is important, because stopping early is a common cause of recurrence.

Will hair grow back after tinea capitis?

In most cases, yes. Once the fungus is cleared, hair usually regrows over 3 to 6 months. Permanent hair loss can occur after a severe kerion or favus, which can scar the follicles. Early treatment lowers the risk of scarring.

Can adults get tinea capitis?

Yes, but it is uncommon. Adults more often carry the fungus without symptoms and pass it to children. When adults do get it, it is often in women after menopause or in people with weakened immunity. Treatment is the same: oral antifungals plus medicated shampoo.