The role of biologics in the treatment of chronic granuloma annulare

Background Granuloma annulare (GA), a benign inflammatory skin disease, is considered a Th1-type delayed hypersensitivity reaction. Localized GA is likely to resolve spontaneously, whereas disseminated GA (DGA) may persist for decades and can be resistant to treatment. Biologics including TNF-alpha inhibitors have been proposed and utilized as salvage therapy for GA and other related diseases, interstitial granulomatous dermatitis (IGD), and actinic granuloma (AG). Methods A systematic review was conducted using the combination of search terms "granuloma annulare," "interstitial granulomatous dermatitis," or "actinic granuloma" and either "biologics," "etanercept," "adalimumab," "infliximab," "ustekinumab," "ixekizumab," "secukinumab," "guselkumab," "golimumab," "brodalumab," "tildrakizumab," or "certolizumab" from the years 1970-2017. Results Review of the literature revealed that 79.3% of the patients with GA, IGD, or AG who had been treated with demonstrated TNF-alpha inhibitor therapy a clinical response. Conclusions TNF-alpha inhibitor therapy has been used to treat chronic GA, IGD, and AG that involved extensive body surface areas. However, the literature is limited to case series lacking control groups. Randomized, controlled trials are required to establish evidence-based treatment of GA and related cutaneous, granulomatous conditions.