How To Test For Ringworm Of The Scalp

Ringworm of the scalp creates bothersome red ring-shaped spots on the skin. A simple test can be performed by your doctor to check for ringworms. Ringworm is believed to be an infection that you get from worms, but it is actually a fungal infection. Ringworm is known to be spread from soil to person, animal to person, or person to person. A proper diagnosis can be done by its location and appearance or by skin scrapings or culture. Here are some ways your doctor will test for ringworm of the scalp.


  1. Doctors use the potassium hydroxide (KOH) solution preparation to find out whether a fungal infection is present on your scalp. A doctor or nurse takes a sample of skin by lightly scraping your scalp that is scaling or flaking to test for ringworm on your scalp. Your doctor will also ask you about possible exposure to contaminated areas or contact with people or animals with ringworm.
  2. Doctors take a sample of hair from the scalp area by rubbing a clean new toothbrush, wet gauze or a sample dish on the infected ringworm area. The doctor or nurse will pull ten to twelve broken hairs from the infected area on your scalp and place them on a slide with the (KOH) solution and gently heat it. The fungus cells are then visible with a microscope. If a sample shows fungus, treatment may include an antifungal medication.
  3. Another test for ringworm of the scalp is a fungal culture or skin culture. This test can identify the type of fungus that is causing infection on your scalp. Usually a culture is only done if the diagnosis is difficult or the skin condition is not responding to treatment. This test may take up to four weeks because it takes time for the fungus to grow. 

Tips and Warnings:


  • Ringworm is typically not contagious once treatment has begun.
  • An over the counter antifungal cream, ointment or lotion is prescribed to treat ringworm.
  • Shampoos and suspensions are additional medicines that help cure ringworm.
  • You should see results within four weeks. If not, contact your health provider.



U.S. Department of Human Health & Services

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