Granuloma annulare — Clinical Case (Wikimedia Commons)

Diagnosis: Granuloma annulare

Granuloma anulare. Clinical photograph sourced from Wikimedia Commons (CC BY-SA 4.0). Attribution: Mravlja Matjaz.

Clinical Presentation

Localized (most common): flesh-colored to erythematous, annular plaques with raised borders and central clearing on dorsal hands/feet. Generalized: widespread papules, often truncal. Subcutaneous: firm nodules in children, often pretibial.

Clinical History

Often asymptomatic and incidentally discovered. May follow trauma or insect bites. Localized form is usually self-limited (resolving within 2 years in 50%). Generalized form may be associated with diabetes, dyslipidemia, thyroid disease.

Treatment

Localized: often observation (self-limited). Potent topical/intralesional corticosteroids. Cryotherapy. Generalized: phototherapy (NB-UVB, PUVA), dapsone, hydroxychloroquine, biologics (dupilumab, JAK inhibitors in refractory cases).

Differential Diagnosis

Tinea corporis, Annular lichen planus, Necrobiosis lipoidica, Sarcoidosis, Erythema annulare centrifugum, Morphea

Key Learnings

KOH preparation helps exclude tinea corporis. GA lacks scale (unlike tinea — 'the ringworm that doesn't scale'). Palisading granulomas with mucin deposition on histopathology are characteristic. Screen for diabetes in generalized GA.

Tags: granuloma annulare, granulomatous, benign, annular