Granuloma Annulare: A Harmless Ring-like Rash that Can Mimic Ringworm

Granuloma annulare (gran-U-LOW-muh an-u-LAR-E) is a fairly common skin condition. The cause of granuloma annulare (GA) is unknown. It is a benign and often self-limited skin condition. Self-limited means that the condition will resolve overtime even in the absence of treatment. The lesions may be skin colored, pinkish or purplish in color and usually have a raised arc or ring-like shape that sometimes is mistaken for ringworm by non-dermatologists. Unlike ringworm, granuloma annulare is not scaly and not itchy. In fact, it’s rarely associated with any symptoms. The lesions most commonly occur on the hands and arms, but can occur anywhere on the body (face involvement is not common). In rare cases, it can have a more generalized distribution.

The diagnosis of GA is usually very straightforward for the dermatologist, who will often make the diagnosis through simple clinical exam. In some cases a biopsy may be done to solidify the diagnosis, but this is generally not necessary. No laboratory tests help confirm the diagnosis. Given the self-limited nature of granuloma annulare, treatment is optional. About half the cases will resolve within a couple of years, though reoccurrence is possible.  First-line treatment includes high-potency topical corticosteroids. For thicker lesions, injecting them directly with corticosteroids is very helpful.

Follow David Robles, MD, PhD