Granuloma annulare is a benign, usually self-limited condition of unknown cause. It usually consists of bumps or lumps in the skin most often less than a quarter of an inch in diameter, which tend to be arranged in a ring-like distribution under the skin. Although it may appear at any age, it occurs primarily in children and young adults and affects women more commonly then men. A number of treatments are used, but their effectiveness is difficult to measure because this condition often spontaneously clears. Recurrence and flares are also very frequent.
Granuloma annulare generally occurs in four clinical types— localized, generalized, perforating, and deep.
Localized granuloma annulare, the most common type, presents with a limited number of flesh-colored to red or purple, 1-5millimeter bumps in the skin, often arranged in a semi-circular or circular pattern with a tendency to spread away from the center. They are found most commonly on the backs of the hands and feet, although involvement of the arms, legs, trunk, and face may occur. In about half the patients, only one ring of these bumps may be present.
The generalized form occurs in only 1% of patients. The spots may number in the hundreds and may be distributed over the trunk, neck, and the outter bend of the elbows. Other areas may be involved.
Perforating granuloma annulare is characterized by similar bumps usually with a central dell or pinpoint indention.
The fourth type, subcutaneous granuloma annulare, or deep granuloma annulare, consists of larger, usually flesh colored, painless nodules, deeper in the skin and fat. This form generally involves the lower legs, hands, scalp and occasionally the eyes.