What is ringworm of the scalp?
Ringworm of the scalp is a fungus infection of the hair. It causes:
- Round patches of hair loss that slowly increase in size
- A black-dot, stubbled appearance within the bald spots of the scalp from hair shafts that are broken off at the surface (note: the dots are blond in blond-haired children.)
- Sometimes scaling on the scalp
- Mild itching of the scalp
- Sometimes ringworm on the face (a ring-shaped, pink rash with a raised border and a clear center)
Children who get ringworm of the scalp are usually 2 to 10 years old. A positive microscope test (KOH prep) or fungus culture is needed to confirm the diagnosis.
What is the cause?
Over 90% of the cases of ringworm of the scalp are caused by Trichophyton tonsurans, a fungus that infects the hairs and causes them to break. A worm does not cause ringworm.
Ringworm is usually transmitted by other children who are infected. Combs, brushes, hats, barrettes, seat backs, pillows, and bath towels can transmit the fungus.
Less than 10% of cases are caused by a fungus from infected animals, such as kittens and puppies. The animal-type of fungus causes more scalp irritation, redness, and scaling. If your child has the animal-type of fungus, he is not contagious to other children.
How long does it last?
Ringworm of the scalp is not dangerous. Without treatment, however, hair loss and scaling may spread to other parts of the scalp.
Some children develop a kerion, which is a boggy (soft), tender swelling of the scalp that can drain pus. Kerions are an allergic reaction to the fungus, not a bacterial infection. They get better when you use antifungal medicine.
Hair normally grows back 6 to 12 months after successful treatment. In the meantime, your child can wear a hat or scarf to hide the bald areas.
How is it treated?
Oral antifungal medicine
The main treatment for ringworm of the scalp is a prescription antifungal medicine taken by mouth. Give the dosage prescribed by your healthcare provider. This medicine is best absorbed by the stomach if your child takes it with fatty foods such as milk or ice cream.
Antifungal creams or ointments are not an effective treatment because they can't reach the fungus deep in the hair roots.
If you wash your child's hair with a nonprescription antifungal shampoo, he will be less contagious and able to return sooner to child care or school. A shampoo such as Nizoral or Head and Shoulders Intensive kills ringworm spores. Lather and leave it on your child's scalp for 10 minutes before rinsing. Use the antifungal shampoo twice a week for 1 month. On other days, use a regular shampoo. Avoid putting any oil or ointment on the scalp because it increases contagiousness of the ringworm.
Ringworm is mildly contagious. Without antifungal medicines, about 5% of children in contact with an infected child at school get infected. However, 25% of siblings (close contacts) get ringworm if it is not treated. After your child has started taking the prescription and washed his hair once with antifungal shampoo, he is not contagious and can return to school. Warn your child not to share combs, brushes, hats, etc. Siblings with an itchy scalp or scalp rash should be examined. Pets with a skin rash or sores should be examined by a vet.
It does not help to shave your child's hair, give him a close haircut, or force him to wear a protective skull cap. This has no health benefit and will make your child self-conscious.
In 6 weeks return to your healthcare provider's office to be certain the ringworm has been cured. If the ringworm is not yet cured, your child will need to take a different medicine.
When should I call my child's healthcare provider?
Call during office hours if:
- The area with ringworm looks infected with pus or a yellow crust.
- The ringworm continues to spread after 2 weeks of treatment.
- You have other questions or concerns.
Written by Barton D. Schmitt, MD, author of “My Child Is Sick,” American Academy of Pediatrics Books.
Published by RelayHealth.
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