Granuloma annulare or GA is a skin condition identified by circular patterns of bumps on the skin. GA is a chronic, reoccurring disorder that affects women more often than men. Though the condition can affect people of all ages, it is most common in children and young adults.
There are five known variants of granuloma annulare. The localized form of the condition is seen most frequently. Linear, perforating, general or disseminated, and subcutaneous granuloma annulare are less common. Some variants appear to run in families, but there is no concrete evidence that GA is a hereditary disorder.
Symptoms of GA vary between individuals, but all five variants cause small, firm bumps on the skin. Doctors may call these red, yellow, or skin-colored bumps lesions, nodules, or papules. They occur in circular or semicircular rings with diameters of approximately two inches but can be less than half an inch in some cases.
Granuloma annulare can affect any part of the body. Most skin lesions occur on the feet, hands, ankles, and fingers, especially in young adults. The forehead, abdomen, and neck are the second most commonly affected areas. Lesions are almost always symmetrical and occur on both sides of the body, although there are exceptions.
Localized granuloma annulare usually occurs in one specific area of the body. Skin lesions from localized GA are almost always painless and heal quickly. Generalized or disseminated granuloma annulare occurs in several areas simultaneously. This type is most strongly associated with diabetes mellitus. The skin lesions or bumps are smaller and occur in larger numbers than those associated with localized GA, and are often pruritic (itchy) and uncomfortable.
Subcutaneous granuloma annulare is more common in children than adults and is characterized by a single nodule or mass under the skin's surface. Nodules usually develop on the scalp, arms, and legs. Perforating granuloma annulare causes bumps on the skin that become pustules. The bumps have a yellow center and leak clear fluid. The skin lesions develop a crust and leave a scar as they heal. Sometimes pustules coalesce or grow together, forming large plaques. Linear granuloma annulare is very rare and affects the fingers.
Most cases of granuloma annulare are idiopathic, which means there is no known cause. Possible triggers include minor skin injuries, medications, animal or insect bites, sun exposure, vaccinations, and tuberculin skin tests. GA triggered by vaccines or skin tests fades away within a few days or weeks. The condition is also a possible complication of pseudorheumatoid nodules or shingles from the herpes zoster virus and other viral infections, especially hepatitis.
Diabetes mellitus, autoimmune disorders, and thyroid disease appear to be risk factors for developing granuloma annulare, although most people with these conditions will never develop GA. Cancer can trigger granuloma annulare, especially in older people. When prompted by cancer, GA is usually severe, and skin lesions rarely respond to treatment.
Flare-ups of granuloma annularae that result in skin lesions usually enter spontaneous remission within a few weeks. This means the lesions disappear without medical intervention, although in many instances they reappear again. Most people with localized GA stop experiencing flare-ups in fewer than five years. The generalized form often heals spontaneously and reappears months or years later. Approximately 25% of non-localized GA cases affect people for more than five years and sometimes last longer than ten years.
Doctors do not recommend treatment if skin lesions are not itchy or painful because there have been only limited studies into GA treatments. Trial and error is necessary to find an appropriate and effective treatment for individual cases. Options include topical steroid creams, cryotherapy to freeze the lesions, and laser therapy. Injected steroids near affected areas and short-term oral medications can also provide relief.
Generalized forms of granuloma annulare are difficult to treat. Oral, topical, or injectable steroids are usually the first option, but steroids are most effective before the lesions spread to multiple areas. The bumps almost always return when the person stops taking steroid medication, but ongoing steroid treatment has many side effects. Phototherapy is the second most common treatment method. It involves exposing affected areas of skin to ultraviolet light. Doctors may employ UVA1 phototherapy, PUVA photochemotherapy, or photodynamic therapy.
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