Botulinum Toxin-Induced Nodules: A Review and Report of Five New Cases

Background

Botulinum toxin, commonly used for cosmetic and therapeutic purposes, is generally safe. However, rare complications, such as nodular granuloma formation at injection sites, can arise, leading to significant distress for affected patients.

Objective

To analyze the clinical presentation, etiopathogenesis, diagnosis, and management of botulinum toxin-induced nodules, consolidating existing knowledge and introducing five new cases from our practice.

Methods

A systematic review of the literature was conducted, identifying reported cases of nodules following botulinum toxin injections. Data from 23 cases, including 5 new cases, were analyzed to identify common patterns. A stepwise algorithmic approach for diagnosis and management was proposed.

Results

Nodules developed weeks to months postinjection. Histopathology revealed granulomatous inflammation, confirming the diagnosis. Etiologies included infectious causes (e.g., nontuberculous mycobacteria) and noninfectious causes (e.g., foreign body reactions and sarcoidal granulomas). Management strategies varied based on etiology, ranging from conservative approaches to systemic immunosuppressants or antimicrobial therapy.

Conclusion

Botulinum toxin-induced nodules, though rare, represent a significant complication. Preventive measures, such as aseptic techniques and thorough patient screening, are crucial. Our findings underscore the importance of cause-directed treatments and propose an algorithmic approach to enhance diagnosis and management.