Granuloma Annulare: Epidemiology, Clinical Variants, Pathogenesis, and Treatment

Granuloma annulare (GA) is a rare, often under-studied skin disease with no FDA-approved treatments, so management is largely off-label and based on clinical experience. It is more common in women, often appears in middle age, and is seen frequently in white women. GA is associated with dyslipidemia, thyroid disease, and diabetes, and may also be linked to autoimmune connective tissue disease, HIV, hepatitis, and, especially in older patients with generalized or atypical disease, hematologic malignancies; age-appropriate cancer screening is recommended, with more focused evaluation in higher-risk cases. Clinically, GA presents as pink-to-brown papules or plaques on the extremities, often with minimal scale, a raised border, and sometimes central hypopigmentation; there are localized, generalized, papular, patch, subcutaneous, perforating, and other variants. Histology typically shows interstitial or palisading histiocytic inflammation with mucin and may include eosinophils. Pathogenesis appears to involve overlapping Th1 and Th2 immune responses with macrophage activation and tissue damage, much of it JAK-STAT mediated. Many localized cases can be observed or treated with potent topical steroids, intralesional steroids, calcineurin inhibitors, or topical JAK inhibitors. For generalized GA, a stepwise approach often begins with hydroxychloroquine, then narrow-band UVB, doxycycline or pentoxifylline, then TNF inhibitors, with methotrexate or oral JAK inhibitors as options for refractory disease. The presenter emphasized that GA treatment should be individualized based on severity and patient preference.