Successful Treatment of Cutaneous Foreign Body Granuloma with JAK Inhibitor Abrocitinib and Prednisone: A Case Report.

Background: Foreign body granuloma (FBG) formation is linked to chronic persistent cutaneous inflammation, representing a severe delayed complication characterized histologically by infiltration of multinucleated giant cells and aggregation of lymphocytes. In filler-induced FBG following cosmetic injections, implanted materials represent a key driver of sustained inflammatory responses. Achieving complete resolution remains challenging, with current therapeutic outcomes for FBG being suboptimal. Emerging evidence suggests that Janus kinase (JAK) inhibitors may constitute a promising therapeutic strategy for refractory granulomatous conditions.

Objective: This case report describes the successful management of FBG using JAK inhibitors and synthesizes existing literature to evaluate the efficacy, safety, and potential mechanisms of abrocitinib in treating filler-induced cutaneous FBG.

Methods: We present a case of post-filler FBG that presents with multiple smooth-surfaced, hemispherical lesions (3-5 mm in diameter) distributed across the entire facial region. The patient was treated with oral abrocitinib (100 mg daily) and prednisone (30 mg daily, tapered over 9 weeks). Clinical outcomes were assessed weekly for 13 weeks through serial clinical photography, dermoscopy, reflectance confocal microscopy, and multispectral imaging. Adverse events, including rash exacerbation, vomiting, dizziness, and fever, were systematically monitored. A comprehensive literature review was conducted to elucidate JAK inhibitors' therapeutic rationale in filler-associated FBG.

Results: The patient achieved complete granuloma resolution within 13 weeks following failed corticosteroid monotherapy. No treatment-related adverse effects were observed during the one-month follow-up period, supporting the favorable safety profile of this therapeutic approach.

Conclusion: This report provides preliminary evidence for JAK inhibitors' efficacy in managing refractory filler-induced FBG. Large-scale controlled trials are warranted to validate long-term safety and therapeutic benefits.