Scalp ringworm (tinea capitis): the signs, how it spreads and how it's treated

Scalp ringworm is a fungal infection of the scalp that involves both the skin and the hair. ² Its medical name is tinea capitis. ¹ Despite the name, it is not caused by worms. ⁴ It most often affects children, but it can occur at any age. ¹

It is contagious, and it spreads through people, shared objects and animals. ² Treatment is medicine taken by mouth, because topical agents cannot reach the root of the hair follicle. ^{1 2} Medicated shampoo has a supporting role: reducing the spread of spores. ²

What causes it

Scalp ringworm is caused by mold-like fungi called dermatophytes. ¹ These fungi can live on the dead tissue of the hair, nails and outer skin layers. ¹ They grow well in warm, moist areas. ¹ After entering the outer layer of the scalp, the fungus grows down into the hair follicle and the hair shaft. ² Infected hairs can break off, leaving small black dots. ^{1 2}

Related ringworm infections include athlete's foot and jock itch. ¹ In the United States, the most common cause is a fungus called Trichophyton tonsurans, which passes between people. ² In New Zealand, Europe and Asia, the most common cause is a fungus that originates in cats. ²

Who gets it

DermNet says scalp ringworm mainly affects children before adolescence. ² Cases peak between the ages of three and seven years. ² It can also affect adults, particularly those with a weakened immune system. ² MedlinePlus says that in many cases it gets better on its own after puberty. ¹

DermNet lists risk factors including animal contact, household crowding, lower socioeconomic status, warm humid environments and contact sport. ² MedlinePlus adds that infection is more likely with minor scalp injuries or infrequent hair washing. ¹ Skin that stays wet for a long time, such as from sweating, also raises the chance. ¹ Ringworm in general is a common infection. ⁴

What it looks like

Symptoms can include hair loss, dry scaly areas, redness and itch. ² DermNet says partial hair loss with some degree of inflammation is characteristic of all types. ² On the scalp, the rash may not look like the usual ring. ⁴ It may look red or darker than the surrounding skin, depending on skin tone. ⁴ Its color may be less noticeable on brown and black skin. ⁴

MedlinePlus says you may also have a low-grade fever of around 100°F to 101°F, or swollen lymph nodes in the neck. ¹ The infection may extend to the eyebrows and eyelashes. ² The American Academy of Dermatology says scaly bald patches, often with sores or blisters that open and ooze pus, often mean a fungal infection on the scalp. ⁵

How it spreads at home and school

Ringworm can spread quickly. ¹ You can catch it through direct contact with ringworm on someone else's body. ¹ DermNet notes this includes people who carry the fungus without symptoms. ²

Shared objects can carry it too. ¹ DermNet lists hairbrushes, hats, towels, bedding, couches and toys. ² It says fungal spores may stay viable on these for months. ²

Pets can spread it, particularly cats. ¹ DermNet says animal fungi come from household pets, especially kittens, and from stray cats and dogs. ² These fungi can then pass from person to person. ² Catching ringworm from soil is less common. ⁴

For school, the NHS says it is fine for a child to go once they have started treatment. ⁴ It also suggests letting the child's teachers know. ⁴

How it is diagnosed

A health care provider will look at the scalp for signs of ringworm. ¹ DermNet says it is usually suspected on sight but should be confirmed with microscopy and culture. ² Scrapings or plucked hairs are checked under a microscope, which can confirm it quickly. ² A fungal culture identifies the fungus, and so the possible source of infection. ² Culture is slow, taking up to 4 weeks, so treatment usually starts before the result is back. ²

A Wood lamp examination can show infected hairs glowing, but few fungi cause this. ² Scalp dermoscopy is fast and non-invasive. ² It can help confirm the infection so treatment can start while culture results are pending. ² Our guide to seeing a dermatologist about hair loss covers what an appointment involves.

Why creams are not enough

DermNet says tinea capitis always requires at least 4 weeks of medicine that works through the whole body. ² The reason is that topical agents cannot penetrate the root of the hair follicle. ² MedlinePlus says a provider will prescribe medicine taken by mouth, for 4 to 8 weeks. ¹ The NHS says scalp ringworm usually needs prescription antifungal tablets and shampoo. ⁴

Medicated shampoo, such as one with ketoconazole or selenium sulfide, is part of home care. ¹ MedlinePlus says shampooing may slow or stop the spread of infection, but it does not get rid of ringworm. ¹ The NHS stresses using antifungal medicine for the right amount of time, even if the rash has gone away. ⁴

Two things are worth knowing ahead of time. With the inflammatory forms, a second rash may appear, particularly after treatment starts. ² DermNet calls this an id reaction. ² Ringworm may also be hard to get rid of, and it may come back after treatment. ¹

Steps for the whole household

Scalp ringworm involves the whole home, not just one person. These are the steps the sources describe.

• Check everyone. DermNet says all household members should be screened and treated at the same time if affected. ²
• Check pets. When the fungus comes from animals, family pets should be checked by a veterinarian. ² The NHS mentions patches of missing fur as a possible sign. ⁴
• Shampoo for others. MedlinePlus says other children in the home may want to use the shampoo. Adults only need it if they have signs. ¹
• Wash towels hot. Use hot, soapy water and the hottest dryer heat the care label allows, each time the infected person uses them. ¹
• Soak combs and brushes. MedlinePlus suggests 1 hour a day in 1 part bleach to 10 parts water, for 3 days in a row. ¹
• Stop sharing. No one in the home should share combs, hairbrushes, hats, towels, pillowcases or helmets. ¹
• Hands off. The NHS suggests washing hands after touching animals or soil. Scratching could spread the rash to other parts of the body. ⁴

Why early treatment matters for hair

The American Academy of Dermatology says that, left untreated, scalp ringworm can lead to hair loss. ³ MedlinePlus says it may cause permanent hair loss and lasting scars. ¹ DermNet says severe inflammatory tinea capitis may result in areas of permanent hair loss. ² By contrast, it says the non-inflammatory form carries an excellent outlook with appropriate and early treatment. ²

The AAD says the sooner you find the cause of hair loss, the better your outcome. ³ The NHS advises starting ringworm treatment as soon as possible. ⁴

DermNet notes that hair loss can cause real distress, especially when bald patches are permanent. ² That feeling deserves to be taken seriously. So does the choice to simply live with a patch. Our guide to scarring hair loss explains more about permanent patches.

When to get help

The NHS lists ringworm on the scalp among the reasons to see a doctor. It usually needs prescription tablets and shampoo. ⁴ The NHS also lists a weakened immune system, for example from chemotherapy, steroids or diabetes. ⁴ MedlinePlus says to contact a provider if you have symptoms and home care is not enough. ¹ A painful, swollen area with pus spots may be a kerion, which may result in permanent hair loss. ² For other causes of a sore or flaky scalp, see itchy scalp and hair loss: when to get it checked.

Conditions it can be mistaken for

Many scalp conditions can cause patchy hair loss, inflammation or scaling. ² DermNet points out some differences.

• Alopecia areata and trichotillomania cause patchy hair loss, but the patches are not scaly. ²
• Seborrheic dermatitis, atopic dermatitis and scalp psoriasis may mimic the non-inflammatory form. Their scale is usually more diffuse. ²
• Bacterial infections of the follicles and skin may resemble the inflammatory form. ²

The short version

Scalp ringworm is a contagious fungal infection that most often affects children. ^{1 2} It needs medicine taken by mouth, because topical agents cannot reach the root of the follicle. ² Medicated shampoo may slow or stop the spread, but it does not get rid of ringworm. ¹ Family members and pets should be examined too. ^{1 2} Left untreated, it can lead to hair loss. ³ A patchy, scaly scalp is worth having looked at early.

General information, not medical advice. This article was drafted with AI assistance and checked against the sources listed above. Nobody at Balds is a doctor. If something here is wrong or out of date, tell us.