# Serum Sickness After Cosmetic Botulinum Toxin Type A Injections

## TL;DR

A rare case of serum sickness after cosmetic Botox injections highlights the need for awareness of immune reactions to botulinum toxin.

## Contribution

Reports a novel case of serum sickness following cosmetic Botox injections and discusses hypersensitivity mechanisms.

## Key findings

- Serum sickness occurred after cosmetic Botox administration, indicating a systemic immune response.
- Hypersensitivity reactions to BoNT-A may involve complexing proteins and formulation excipients.
- The case underscores the need for vigilance in identifying immune responses in cosmetic settings.

## Abstract

Botulinum toxin type A (BoNT-A) is widely used in therapeutic and cosmetic settings for neuromuscular and aesthetic indications. Although generally well tolerated, reports of hypersensitivity reactions—ranging from localized erythema to systemic immune syndromes—underscore its immunological complexity. This case report and literature review demonstrates a novel case of serum sickness following cosmetic Botox® (onabotulinumtoxin-A, Allergan Aesthetics, an AbbVie company, Irvine, CA) administration, categorizes hypersensitivity reactions according to the Gell and Coombs classification (Types I–IV), explores the role of complexing proteins and formulation excipients, and highlights emerging clinical concerns. This will underscore the need for greater vigilance in identifying systemic immune responses to BoNT-A especially within the cosmetic medicine industry.

Level of Evidence: 5 (Therapeutic)