Granuloma annulare, which is a frequent companion to diabetes, causes a localized or generalized rash characterized by small bumps that link to form circles.
Granuloma annulare, which is suspected of having an autoimmune origin, is a benign autoimmune-related dermatological condition that can occur in people with autoimmune disorders, including autoimmune thyroiditis, Graves’ disease, and insulin-dependent diabetes mellitus. Granuloma annulare is also known to occur in patients with a family history of autoimmune polyglandular syndrome type II. Older children and young adults are most often affected although people of any age may be affected. Females are affected twice as often as males.
Symptoms
Granuloma annulare causes a raised symmetrical (occurring evenly on both sides of the body) rash characterized by bumps that often expand or connect to form rings. The bumps or lesions in granuloma annulare are usually skin-colored, pearly white, red, or purple. The center of each ring is often slightly depressed with a clear area although the center of the ring may be pale or light brown. The area of the rash may be tender although it is generally not painful. The rash often tends to recur, resolving after a few years.
The rash in granuloma annulare may be localized to small areas or diffuse. Localized granuloma annulare usually develops over the knuckles, elbows, knees, and other joints. It can also develop on areas of the skin prone to injury such as the back of the hands or the tops of the feet.
Granuloma annulare may be confused with ringworm or the characteristic erythema migrans rash seen in Lyme disease. Besides its association with autoimmune disorders, granuloma annulare is associated with Bacillus Calmetter-Guerin vaccinations, certain drugs, such as allopurinol used for gout and zalcitabine, viral infections, including human parvovirus B19 and hepatitis C, as well as certain malignancies such as Hodgkin's disease and breast and ovarian cancers.
Generalized or Diffuse Granuloma Annulare
In generalized granuloma annulare, which primarily affects people younger than 10 years or older than 40 years, the rash is widespread, usually covering the face, neck, arms, trunk, and legs. The bumps in generalized granuloma annulare are typically smaller and the rings aren’t as noticeable. However, they are more likely to cause severe itching.
Diagnosis
Granuloma annulare is diagnosed with a biopsy of the skin bumps. Tissue studies of lesions shown white blood cell infiltration and inflammation with blue-gray degenerated elastic fibers within the cell cytoplasm.
Treatment
Localized granuloma annulare often resolves on its own without treatment. Generalized conditions, however, usually need to be treated. Available treatments include isotrentnoin, topical corticosteroids, and ultraviolet treatment (PUVA) although the rash often returns after treatment is discontinued. In these recurring cases, intralesional corticosteroids, liquid nitrogen cryotherapy, pentoxifylline, cylosporineDapsone, and potassium iodide may be used.
Resources:
Dirk Kappeler, Amineh Troendle, and Bruno Mueller, Localized granuloma annulare associated with autoimmune thyroid disease in a patient with a positive family history for autoimmune polylandular syndrome type II, Letter To the Editor, European Journal of Endocrinology, 2001, 146: 101-102.
Martha Arroyo, Generalized granuloma annulare, Dermatology Online Journal, 9 (4), Feb 2002.
F Vazquez-Lopez, M Gonzalez-Lioez, C Raya-Aguadco, and N Perez-Oliva, Localized granuloma annulare and autoimmune thyroiditis: A new case report, Journal of the American Academy of Dermatology, Nov, 2000; 43: 943-945.
