Adverse Reactions Following Intradermal Injection of Exosome‐Based Formulations: A Case Series

BACKGROUND: Exosome-containing formulations have recently gained popularity in aesthetic dermatology because of their regenerative and anti-inflammatory properties. Although approved for topical use, intradermal injection of these cosmetic products remains off-label and unregulated in many countries, including South Korea. AIMS: To describe four cases of severe cutaneous adverse reactions following the intradermal injection of unregulated exosome-based formulations. METHODS: Four adult women developed persistent erythema, nodules, granulomatous inflammation, and scarring following intradermal administration of exosome-containing products in a nonclinical setting. The clinical course, treatment, and outcomes of the patients were documented. RESULTS: All the patients experienced persistent inflammatory lesions. Treatments included corticosteroids (systemic and intralesional), laser therapy, and surgical removal. The outcomes varied, with all patients experiencing incomplete resolution and residual scarring. CONCLUSION: Intradermal injection of unapproved exosome-based formulations may cause serious and persistent cutaneous complications. This case series underscores the need for regulatory enforcement, practitioner education, and public awareness to prevent off-label use and protect patient safety in aesthetic practice.