Persistent Unilateral Facial Inflammation Associated With a Calcium Hydroxylapatite-Compatible Foreign-Body Reaction: A Case Report

Calcium hydroxylapatite (CaHA) is a widely used biostimulatory dermal filler, although persistent inflammatory complications may occur.We report the case of a 23-year-old woman who developed progressive unilateral inflammation of the left midface and lower face several weeks after CaHA injection.Symptoms persisted for approximately two years despite previous diagnoses and treatments.At presentation, she had facial asymmetry, persistent edema, induration, severe pain, and mechanical allodynia.High-resolution ultrasound showed diffuse abnormalities of the subcutaneous adipose tissue, consistent with edema and inflammatory involvement.An incisional biopsy demonstrated fibrous tissue containing exogenous spherules compatible with CaHA and a foreign-body granulomatous reaction.The patient received a multimodal regimen comprising oral and intralesional corticosteroids, pregabalin, collagenase, and lipase.Clinical and ultrasound improvement was observed during ongoing treatment, with residual tissue abnormalities at the latest follow-up.Ultrasound findings did not establish histological resolution of fibrosis.Because interventions were administered sequentially and in combination, improvement cannot be attributed to any single treatment.This case illustrates the complementary roles of clinical assessment, ultrasound, and histopathology in evaluating persistent inflammation after CaHA injection.