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* This section is provided free of charge to you from the American Academy of Dermatology's library. We do not treat all conditions listed here, nor do we perform all treatments discussed in this section. This is purely meant to be a reliable resource for patients with an interest in, or questions about, a wide array of dermatologic topics.
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Granuloma annulare is a skin condition that is often confused with ringworm, a fungal skin infection. It is important to see a board-certified dermatologist for the correct diagnosis.
What Causes Granuloma Annulare?
The cause of granuloma annulare is unknown; however, dermatologists and researchers believe the immune system may play a role. In some cases, there may be a link between granuloma annulare and HIV, thyroid disease, diabetes or other diseases.
For some people, a skin injury, insect bite, infection or sun exposure seems to trigger the condition.
Localized granuloma annulare
What Does Granuloma Annulare Look Like?
Most people develop “localized” granuloma annulare, which causes a round, firm, smooth-feeling bump on the skin. This bump will become ring-shaped, resembling a donut, with a center of clear skin. The affected skin can be pink or purple, or appear a bit darker than your skin color. Since this spot usually does not peel or itch, many people never notice it.
Some people may develop a widespread rash of flesh-colored or purplish bumps. These tiny bumps can appear in many places on the skin.
Granuloma annulare can spread, covering more skin before it starts to clear. This type is called “generalized” or “disseminated” granuloma annulare. It is sometimes itchy.
Children with granuloma annulare may develop harmless, firm lumps under their skin on the scalp, hands and legs.
Where Does Granuloma Annulare Appear?
Granuloma annulare can form anywhere on the skin. However, if you have a single spot, it is most likely to appear on the top of your hand or foot, or on your elbow or knee.
Who Gets Granuloma Annulare?
People of all ages can develop localized granuloma annulare, though it is more common in females and those younger than 30.
Generalized granuloma annulare
It is more common for older adults to develop generalized granuloma annulare. Infants rarely get this skin condition.
How Is Granuloma Annulare Diagnosed?
A board-certified dermatologist usually diagnoses granuloma annulare by examining the skin.
To ensure a proper diagnosis, your dermatologist may scrape off a bit of the affected skin or perform a biopsy (remove a small amount of skin). The removed skin will be examined under a microscope.
Your dermatologist may perform a skin scraping or biopsy to rule out the following conditions:
- Ringworm. A fungal skin infection that requires treatment.
- Lyme disease. An infectious disease caused by a bite from a deer tick. Without treatment, Lyme disease can cause serious health problems. A rash from Lyme disease usually looks like a circular pattern on the skin that gets larger with time.
- Insect bites. Depending on the insect, some bites need treatment.
- Sarcoidosis. An inflammatory disease that affects multiple organs in the body, primarily the lungs and lymph nodes.
Sometimes, a blood test is necessary to rule out other possible diseases.
Localized granuloma annulare
Is Treatment Necessary?
Treatment for granuloma annulare is usually not necessary since most people do not notice symptoms.
Granuloma annulare often goes away on its own with time.
Most people see their skin clear in a few months. In some cases, clearing takes longer. Some people have granuloma annulare for years. A granuloma annulare rash also can clear and return later in life.
Generalized granuloma annulare
If you have a type of granuloma annulare that covers a large area of your body or causes a deep growth in your skin, your dermatologistmay recommend treatment. You also may consider treatment if you have noticeable patches and dislike how your skin looks. Your dermatologist will prescribe a treatment tailored to your needs, such as:
- Corticosteroid cream or ointment. Applied to the skin while at home, this prescription medicine helps to clear spots and bumps. It is important to use this medicine as directed, as it may cause unwanted side effects such as thinning skin.
- Corticosteroid injection. Your dermatologist will inject this directly into the spot to help clear it.
- Light therapy. Exposing the skin with granuloma annulare to ultraviolet light in a controlled way can be helpful.
Some people receive a type of light therapy called PUVA, which involves taking a medication called psoralen and then treating the skin with UVA light. Your dermatologist may prescribe this to treat a widespread rash.
Your dermatologist may also prescribe other treatments to help clear stubborn granuloma annulare.
A board-certified dermatologist is a medical doctor who specializes in the diagnosis and medical, surgical and cosmetic treatment of skin, hair and nail conditions. To learn more about granuloma annulare or to find a board-certified dermatologist in your area, visit aad.org/granuloma-annulare or call toll-free (888) 462-DERM (3376).
All content solely developed by the American Academy of Dermatology.
Copyright © by the American Academy of Dermatology and the American Academy of Dermatology Association.
Images used with permission of the American Academy of Dermatology National Library of Dermatologic Teaching Slides
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