Factors Associated With Treatment Response in Granuloma Annulare

Abstract

Background/purpose: Granuloma annulare (GA) is a chronic inflammatory dermatosis with limited effective treatments and inconsistent response rates across modalities. The Goeckerman protocol, consisting of coal tar, phototherapy, and topical corticosteroids (TCS), has demonstrated robust efficacy in other inflammatory dermatoses but has not been systematically evaluated in GA. This study aimed to characterize treatment outcomes across multiple therapeutic approaches, including the Goeckerman protocol, and to explore clinical factors associated with treatment response.

Methods: A retrospective cohort study was performed at Sheba Medical Center (2010-2024) including 240 patients with biopsy-confirmed GA. Treatment modalities included TCS, phototherapy, combination therapy, the Goeckerman protocol, and observation. Responses were dermatologist-assessed as complete, partial, or none. Multivariate logistic regression was used to examine factors associated with treatment response.

Results: Among 240 patients (mean age 55.4 years; 77.5% female), 184 had follow-up data (median 3.0 months). The overall response rate was 58.2% (107/184). Response differed significantly by modality: Goeckerman protocol 93.5% (29/31), TCS + phototherapy 69.6% (16/23), TCS alone 56.3% (49/87), no active treatment 32.4% (12/37), and phototherapy alone 16.7% (1/6). In multivariate analysis, the Goeckerman protocol was the strongest factor associated with treatment response (odds ratio [OR] 32.52; 95% CI 7.45-233.64; p < 0.001), followed by combination therapy (OR 5.79; p = 0.006) and TCS (OR 2.82; p = 0.015). Hyperlipidemia was associated with response in univariate analysis but did not remain significant in the multivariable model.

Conclusions: Treatment modality was the factor most strongly associated with treatment response in this cohort. The Goeckerman protocol demonstrated a notably high response rate compared with other commonly used therapies. Although these findings should be interpreted in the context of a retrospective design and potential selection bias, they suggest that intensive multimodal anti-inflammatory therapy may represent a promising treatment strategy for this challenging condition.

Keywords: Goeckerman protocol; coal tar; granuloma annulare; phototherapy; topical corticosteroid; treatment outcome.