Granuloma annulare may be the result of an immune reaction.
People may have one ring or several and colors vary.
The diagnosis is usually based on the appearance of the skin.
Granuloma annulare usually heals without treatment.

The cause of granuloma annulare is not clear, but doctors suspect it is the result of an immune reaction. Having granuloma annulare does not mean that another disorder is present.
In a few people who have granuloma annulare, certain factors may cause clusters of granuloma annulare bumps to erupt. Such factors include exposure to sunlight, insect bites, skin testing for tuberculosis, bacille Calmette-Gu