Subcutaneous Granuloma Annulare: A Rare Case Associated With Acetazolamide

Area of Science:

• Dermatology
• Pharmacology
• Immunology

Background:

• Granuloma annulare (GA) is a benign granulomatous skin condition.
• Drug-induced GA, including interstitial granulomatous drug reactions (IDG), can mimic idiopathic GA.
• Carbonic anhydrase inhibitors (CAIs) like acetazolamide have been linked to subcutaneous GA (SGA).

Purpose of the Study:

• To report a case of acetazolamide-induced SGA in a pediatric patient.
• To explore the potential immunologic mechanisms underlying CAI-associated granulomatous inflammation.

Main Methods:

• Case report of a 16-year-old female presenting with subcutaneous nodules.
• Histopathological examination of skin biopsy.
• Clinical observation of response to drug discontinuation.

Main Results:

• The patient developed firm subcutaneous nodules on her hands after starting acetazolamide.
• Histopathology confirmed subcutaneous palisading granulomas with central necrobiosis, consistent with SGA.
• Nodules resolved almost completely within two weeks of discontinuing acetazolamide.

Conclusions:

• Acetazolamide can induce subcutaneous granuloma annulare (SGA).
• The mechanism may involve carbonic anhydrase inhibition leading to endothelial cell apoptosis and altered macrophage activation.
• This case expands the understanding of granulomatous inflammation associated with CAIs.