Complex Hypersensitivity and Irritation Reaction (CHAIR) Phenomenon after Cyanoacrylate Closure of Varicose Vein.

Cyanoacrylate glue is a non-thermal, non-tumescent agent used to treat saphenous reflux. It was introduced to overcome heat-related discomfort and complications. Multiple randomized controlled trials using this therapy have demonstrated excellent clinical outcomes at long-term follow-up. However, diffuse injection-site inflammation and systemic urticaria are worrisome complications. In preclinical studies, serial histopathological findings demonstrated acute inflammatory reaction, subacute vasculitis, chronic granulomatous foreign body reaction, fibrotic changes with partial vascular recanalization, and chronic foreign body-type inflammatory response. While the exact nature of this unique complication remains undefined, complex hypersensitivity and irritation reaction phenomena have been suggested based on reported clinical presentations. The incidence of this complication has been reported as ranging from 0.3%-25.4%. Typically, erythematous reactions can occur near treatment sites, with symptoms ranging from mild pruritus and/or erythema that resolves without treatment to recurrent severe inflammation and pruritus requiring nonsteroidal anti-inflammatory drugs, antihistamines, and/or corticosteroids. Surgical excision has been rarely reported in patients with severe intractable inflammation or treatment-site infections. Although several anecdotal studies reported on using antihistaminics or corticosteroids, no effective strategies have been established to prevent this complication.