Granuloma annulare is a fairly common long-lasting skin rash that looks like a ring of small red bumps, usually over the backs of your forearms, hands or feet.
It tends to affect children and young adults, and is slightly more common in females. The cause is unknown.
The rash is usually the only symptom – most people with granuloma annulare are otherwise healthy.
About the rash
The rash may be slightly itchy and there may be a number of rings.
Typically, the rings grow slowly until they are around 2.5-5cm across, becoming flatter and more purple in colour before they eventually fade.
Rarely, the rash may spread all over the body, or there may be one or more firm lumps under the skin of the arms or legs (this is known as subcutaneous granuloma annulare).
Granuloma annulare usually disappears without treatment within two years, although it can sometimes last for many years and new rings may appear.
Granuloma annulare is not infectious or caused by allergies.
What to do
You should contact your doctor if you notice a ring anywhere on your skin that does not go away within a few weeks, so they can rule out other possible causes like a fungal infection.
Because granuloma annulare is harmless, you may not need any treatment for the rash. However, you may wish to consider treatment if the appearance is upsetting you.
How it is treated
There is no effective treatment specifically for granuloma annulare.
Very strong steroid creams or ointments, or steroid injections directly into the rings, may help to clear up the rash. However, steroids must be used carefully, as long-term use can thin the skin. Read about corticosteroids (steroid medication).
Some doctors may suggest freezing the bumps with liquid nitrogen.
Severe or widespread cases can be treated with ultraviolet light therapy (PUVA) or medicines that suppress the immune system – usually imiquimod sachets, tacrolimus or pimecrolimus cream.