A 51-year-old woman presents to the dermatology clinic requesting treatment of a rash on her lower back, which was first noted by a family member approximately 1 year ago. The site is asymptomatic and does not itch or burn. Her medical history is positive for surgically resected papillary thyroid carcinoma, pulmonary sarcoidosis, and gastroesophageal reflux disease. She is a former smoker. Examination reveals a 5-cm, well-demarcated erythematous patch devoid of scale. No similar lesions are noted elsewhere on her body.
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Granuloma annulare (GA) is a benign, self-limited condition of unknown etiology. The entity was first described in 1895 as a “ringed eruption” and formally named in 1902.1 The condition is most common in individuals younger than 30 years of age and women, with a 2.3:1 ratio over men.2
Subtypes of GA include localized, generalized, and subcutaneous.3 The localized subtype usually presents on the dorsal or lateral surfaces of the hands and feet. The classic appearance of localized GA is an annular flesh-colored to erythematous patch or plaque with a slightly elevated border. Generalized GA usually affects adult women and manifests as multiple erythematous to light brown papules and patches. The trunk and upper thighs are primarily involved. Subcutaneous or deep GA occurs mainly in children and is characterized by firm asymptomatic nodules.3
The diagnosis of GA is often made clinically. Biopsy reveals palisading granulomatous inflammation accompanied by dermal collagen degeneration admixed with macrophages, neutrophils, and multinucleated giant cells.4,5
Isolated lesions of GA may be precipitated by trauma although the underlying pathogenesis is uncertain. An immune-mediated type III reaction that induces chronic vasculitis has been postulated5 as well as a type IV delayed hypersensitivity reaction resulting in activation of macrophages and fibroblasts.6 A link to diabetes is supported by several studies and refuted by others.1
Treatment options for localized disease include topical and intralesional steroids and cryosurgery. Many cases resolve spontaneously within 2 years of onset.
Nicole Schnell, PA-C, is a physician assistant at the DermDox Dermatology Center in Bethlehem, Pennsylvania. Stephen Schleicher, MD, is director of the DermDox Center for Dermatology in Pennsylvania, associate professor of medicine at Commonwealth Medical College, and clinical instructor of dermatology at Arcadia University and Kings College.
1. Piette EW, Rosenbach M. Granuloma annulare: pathogenesis, disease associations and triggers, and therapeutic options. J Am Acad Dermatol. 2016;75(3):467-479. doi:10.1016/j.jaad.2015.03.055
2. Smith MD, Downie JB, DiCostanzo D. Review: Granuloma annulare. Int J Dermatol. 1997;36(5):326-333. doi:10.1046/j.1365-4362.1997.00257.x
3. Habif TP. Granuloma annulare. In: Habif TP, ed. Clinical Dermatology. 5th ed. Elsevier; 2010:976-977.
4. Chatterjee D, Kaur M, Punia RPS, Ghalla M, Handa U. Evaluating the unusual histological aspects of granuloma annulare: a study of 30 cases. Indian Dermatol Online J. 2018;9(6):409-413. doi:10.4103/idoj.IDOJ_75_18
5. Dahl MV, Ullman S, Goltz RW. Vasculitis in granuloma annulare: histopathology and direct immunofluorescence. Arch Dermatol. 1977;113:463-467.
6. Umbert P, Belcher RW, Winkelmann RK. Lymphokines (MIF) in the serum of patients with sarcoidosis and cutaneous granuloma annulare. Br J Dermatol. 1976;95:481-485. doi:10.1111/j.1365-2133.1976.tb00857.x