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A 39-year-old woman presents with raised rings on her right hand only. Not knowing the correct diagnosis, another physician prescribed topical steroids and antifungal medicines with no benefit. The diagnosis of granuloma annulare (GA) was made by the typical clinical appearance and the patient was offered intralesional steroids. Triamcinolone acetonide was injected as seen in Figure 173-1, A. The patient noted improvement over the subsequent weeks, but within a month new lesions began to appear on her other hand (Figure 173-1, B). Additional injections were provided and 1 month later the patient had regression of the treated lesions but had new lesions on the right arm (Figure 173-2, A). At the next visit, the patient had new lesions on her feet as well (Figure 173-2, B). The diagnosis of disseminated GA was made and systemic treatment was started.
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GA is a common dermatologic condition that presents as small, light-red, dermal papules coalescing into annular plaques without scale. As in the above vignette, it is often mistaken as nummular eczema or tinea corporis. Distribution, pattern, and lack of scale are important diagnostic clues.
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- GA affects twice as many women as men.1
- The four presentations of GA are localized, disseminated/generalized, perforating, and subcutaneous.
- Of the four variations, the localized form is seen most often.1
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- Benign cutaneous, inflammatory disorder of unknown origin.1
- Disease may be self-limiting, but may persist for many years.
- Reported associations include diabetes mellitus, viral infections (including HIV), Borrelia and streptococcal infections, insect bites, lymphoma, tuberculosis, and trauma.2,3
- One proposed mechanism for GA is a delayed-type hypersensitivity reaction as a result of T-helper-type cell (Th)-1 lymphocytic differentiation of macrophages. These macrophages become effector cells that express tumor necrosis factor (TNF)-α and matrix metalloproteinases. The activated macrophages are responsible for dermal collagen matrix degradation.4
- An association between high expression of gil-1 oncogene and granulomatous lesions of the skin, including GA, ...