This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
Granuloma annulare (GA) is skin disorder that most often causes a rash with red bumps (erythematous papules) arranged in a circle or ring pattern (annular). GA is not contagious and is not cancerous. The rash may be localized or generalized. Localized GA is the most common form of GA (75% of the cases) and usually affects the forearms, hands, or feet. The generalized form of GA (15% of cases) presents with numerous erythematous papules that form larger, slightly raised patches (plaques) anywhere on the body, including the palms of hands and soles of feet. The plaques may or may not be in the ring pattern and can vary in color. Less common forms of GA include subcutaneous, perforating, and patch variants.
The underlying cause of GA is unknown, but there are several factors that may trigger the disorder, including injury to the skin, viral infections, and certain medications and medical diseases. However, most cases of GA develop in healthy people. Some researchers propose unknown genetic factors may increase a person’s risk to develop GA. Diagnosis of GA is made by the appearance of skin lesions and lack of other physical findings or symptoms. GA may be confirmed by a biopsy and tests may be performed to rule out other associated diseases. GA usually goes away without treatment within a few weeks to several years. However GA can sometimes last for decades, especially the generalized form. Steroids creams or injections and other therapies may be used to clear the rash more quickly, but are not successful in all cases, especially for those with the generalized form. Even after GA completely goes away, it may develop again.
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