Granuloma annulare is a chronic skin condition which is characterized by small, raised bumps that form a ring with a normal or sunken center. Granuloma annulare occurs most often in children and young adults, though it can affect people of all ages. Most patients are over age 40, and there is often severe itching. Patients with generalized GA may have a tendency to diabetes mellitus and other internal problems.
The cause is unknown, but granuloma annulare does not damage the general health, and is not infectious or due to allergies. Some types of granuloma annulare have been linked with diabetes but this is very uncommon in the ordinary type. Granuloma annulare is occasionally associated with diabetes, thyroid disease and HIV infection, but most people with granuloma annulare are otherwise healthy.
The rash of GA is symmetrical and formed by skin colored bumps. The bumps often expand or join to form rings. Patients usually notice a ring of small, firm bumps over the backs of the forearms, hands or feet. Occasionally, multiple rings may be found. The center of each ring may be a little depressed, pale or light brown. The centre of each ring is often a little depressed. It usually affects the fingers or the backs of both hands, but is also common on top of the foot or ankle, and over one or both elbows. GA usually has no symptoms, but it may be tender. It may come and go, only to return again.
Most often granuloma annulare is recognised because of its characteristic apppearance. But sometimes the diagnosis is not obvious, and other conditions may be considered. In such cases, a small biopsy will help to establish the cause of the rash. The biopsy shows characteristic necrobiotic degeneration of dermal collagen surrounded by an inflammatory reaction.
Very strong topical steroid creams or ointments are sometimes used to speed the disappearance of the lesions. Injections of steroids directly into the rings may also be effective.
People with large affected areas often benefit from treatment that combines phototherapy (exposure to ultraviolet light) with the use of psoralens (drugs that make the skin more sensitive to the effects of ultraviolet light). This treatment is called PUVA.