Ringworm of the scalp is not really a worm, but a fungal infection. It gets the name ringworm because the fungus makes circular marks on the skin, often with flat centers and raised borders. Also called Tinea capitis, this infection affects your scalp and hair shafts, causing small patches of itchy, scaly skin.
Ringworm is a highly contagious infection that’s usually spread through person-to-person contact or by sharing combs, towels, hats, or pillows. Ringworm is most common in children, but can infect a person of any age.
Fungi called dermatophytes cause ringworm of the scalp. Fungi are organisms that thrive on dead tissue, such as fingernails, hair, and the outer layers of your skin. Dermatophytes prefer warmth and moisture, so they thrive on sweaty skin. Overcrowding and poor hygiene increase the spread of ringworm.
Ringworm spreads easily, especially among children. You can get ringworm from touching the skin of an infected person. If you use combs, bedding, or other objects that have been used by an infected person, you’re also at risk.
House pets, such as cats and dogs, can spread ringworm, too. Farm animals like goats, cows, horses, and pigs can also be carriers. However, these animals might not show any signs of infection.
The most common symptom of ringworm is itchy patches on the scalp. Sections of hair may break off near the scalp, leaving scaly, red areas or bald spots. You may see black dots where the hair has broken off. Left untreated, these areas can gradually grow and spread.
Other symptoms include:
In more severe cases, you may develop crusty swellings called kerion that drain pus. These can lead to permanent bald spots and scarring.
A visual exam is often enough for a doctor to diagnose ringworm of the scalp. Your doctor may use a special light called a Wood’s lamp to illuminate your scalp and determine signs of infection.
Your doctor may also take a skin or hair sample to confirm the diagnosis. The sample is then sent to a lab to determine the presence of fungi. This involves looking at your hair or a scraping from a scaly patch of scalp under a microscope. This process may take up to three weeks.
Your doctor will probably prescribe fungi-killing oral medication and medicated shampoo.
The leading antifungal medications for ringworm are griseofulvin (Grifulvin V, Gris-PEG) and terbinafine hydrochloride (Lamisil). Both are oral medications that you take for approximately six weeks. Both have common side effects, including diarrhea and upset stomach. Your doctor may recommend taking these medications with a high-fat food such as peanut butter or ice cream.
Other possible side effects of griseofulvin include:
- sun sensitivity
- allergic reactions in people who are also allergic to penicillin
Other possible side effects of terbinafine hydrochloride include:
- stomach pain
- loss of taste or change in taste
- allergic reaction
- liver problems, in rare cases
Your doctor may prescribe a medicated shampoo to remove fungus and prevent the spread of infection. The shampoo contains the active antifungal ingredient ketoconazole or selenium sulfide. Medicated shampoo helps prevent the fungus from spreading, but it doesn’t kill ringworm. You must combine this type of treatment with an oral medication.
Your doctor may tell you to use this shampoo a couple times per week for a month. Leave the shampoo on for five minutes, then rinse.
Ringworm heals very slowly. It can take more than a month to see any improvement. Be patient and continue taking all medication as directed.
Your doctor may want to check you or your child in 4 to 6 weeks to make sure the infection is clearing up. It can be difficult to get rid of ringworm, and it’s possible to get the infection more than once. However, recurrences often stop at puberty. Long-term effects include possible bald patches or scarring.
Your child can usually return to school once they start treatment for ringworm, but you should ask your doctor when it’s safe for them to return.
Pets and other family members should be examined and treated if necessary. This will help prevent reinfection. Do not share towels, combs, hats, or other personal items with other family members. You can sterilize combs and brushes that belong to the infected person by soaking them in bleach water. Follow the directions on the bleach container for the proper dilution ratio.
The dermatophytes that cause ringworm are common and contagious. This makes prevention difficult. Because children are especially susceptible, tell your children about the risks of sharing hairbrushes and other personal items. Regular shampooing, hand washing, and other normal hygiene routines can help prevent the spread of infection. Be sure to teach your children proper hygiene, and follow these practices yourself.
It can be hard to tell if an animal has ringworm, but a common sign of infection is bald patches. Avoid petting any animals that have patches of skin showing through their fur. Maintain regular checkups for all pets and ask your veterinarian to check for ringworm.