Delayed Inflammatory Reaction to Hyaluronic Acid Dermal Filler Following Zoledronic Acid Administration: A Case Report.

Zoledronic acid is a bisphosphonate that can be administered intravenously and used to treat several bone disorders. It decreases bone resorption, thereby improving bone mineral density (BMD) and reducing fractures. The Food and Drug Administration (FDA) has approved zoledronic acid for the prevention and treatment of osteoporosis in postmenopausal females and males and for other conditions. Zoledronic acid is generally well tolerated, with most side effects being musculoskeletal or gastrointestinal. Cutaneous side effects include maculopapular rash and other mild skin reactions. Rare severe skin rashes, such as toxic epidermal necrolysis, have been reported. Here, we report the case of a 64-year-old female with a medical history of breast cancer status post-radical mastectomy and chemotherapy presenting with delayed hypersensitivity reaction to a hyaluronic acid dermal filler two days after receiving zoledronic acid intravenously given to maintain bone density, symptoms completely resolved with oral prednisolone 20 mg once daily and cetirizine 10 mg. Cases of delayed inflammatory reaction to hyaluronic acid soft tissue filler have previously been reported in patients who have received vaccination or those with viral infections. However, to our knowledge, there have been no reports of delayed inflammatory reactions to facial hyaluronic acid injections after zoledronic acid administration.