Extensive Foreign Body Granulomas Induced by Calcium Hydroxyapatite Filler

Background: Calcium hydroxylapatite (CaHA) is a biocompatible dermal filler used for soft tissue augmentation and collagen stimulation. While generally well-tolerated, rare cases of delayed onset inflammatory nodules, including foreign body granulomas, have been reported. The mechanism for these reactions remains unclear, with potential contributing factors including large particle size, injection technique, and pathogenic contamination leading to biofilm formation. Case presentation: A 69-year-old female presented with multiple firm, erythematous nodules on the face and neck six months after receiving CaHA filler injections at her esthetician’s house. Histopathologic analysis revealed granulomatous inflammation with foreign body giant cells surrounding birefringent material, consistent with a foreign body reaction to CaHA. Although no biofilm was identified, concerns were raised regarding potential contamination due to the non-sterile injection environment. The patient was treated with oral corticosteroids and weekly intralesional triamcinolone injections, leading to gradual improvement over ten months, though residual nodules remained. Conclusion: This case underscores the potential for granulomatous reactions following CaHA filler injections, especially in non-sterile environments. Given the increasing popularity of soft-tissue fillers, dermatologists should maintain a high index of suspicion for inflammatory reactions and emphasize the importance of sterile injection practices.