Granuloma annulare: what it is, causes and treatment

The NHS describes granuloma annulare as a skin condition that often looks like a ring of bumps. The British Association of Dermatologists (BAD) says it is a common skin condition, benign and not affecting general health, in which a ring of firm bumps (papules) typically occurs on only one or two sites.

The name describes the look: granuloma refers to a cluster of inflammatory cells, and annulare means ring-shaped. Rarely it does not have the characteristic ring shape.

The most common symptom, according to the NHS, is small circular patches of pink, purple or skin-coloured bumps. They tend to affect bony areas such as the back of the hands, fingers, elbows and feet, are usually raised and grow slowly to around 2.5 to 5cm, and may eventually become flatter before gradually fading. It may be harder to see on black and brown skin.

The BAD says in most cases it causes no symptoms, although there could be a mild itch, and the affected skin can feel tender when knocked.

The NHS says granuloma annulare is inflammation in the deep layer of the skin called the dermis. The exact cause is unknown, but some types may be related to other health problems, such as diabetes and thyroid conditions like Graves’ disease.

The BAD says research is ongoing into links with diabetes, dyslipidaemia (abnormal blood fat levels) and thyroid disease, and that the generalised form can be associated with underlying diseases such as diabetes. It is not hereditary. A blood sugar test may be done if symptoms of diabetes are present.

No. The NHS says you cannot catch granuloma annulare from someone who has it, and the BAD says it is not infectious or contagious and is not due to allergies. It is not caused by anything you have done.

A circular rash can also be ringworm, which the NHS says is a common fungal infection usually treated with medicines from a pharmacy. If you are unsure, see a GP.

The NHS says it is harmless and sometimes disappears without treatment, but it can take a long time to clear up (2 to 10 years) and it often comes back. The BAD says there is no specific cure, but in over half of cases it will have disappeared within two years without any treatment, and in 40% of patients it may come back in the future.

The BAD says localised granuloma annulare is limited to a few sites and tends to improve with time, so treatment is usually unnecessary. A skin specialist may suggest treatment if it affects a visible or large area and affects your life, according to the NHS.

The NHS says to see a GP if you have lumps or raised areas of skin that do not go away within a few weeks. The diagnosis is made from the appearance of the skin, and the BAD says a skin biopsy may be arranged in less common types.

A GP can usually diagnose and start simple treatment, and refer you to a dermatologist if it is widespread or difficult to treat. Private dermatology clinics offer the same assessment and treatments such as light therapy; ask what is included. Skin camouflage services are available through some NHS clinics and charities.