Can Botulinum toxin (Botox) injections cause urticaria?

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Last updated: May 17, 2025View editorial policy

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From the Guidelines

Botox injections can cause urticaria, although the exact incidence is not well established, and the risk is considered low. According to a systematic review by the joint task force involving the American Academy of Allergy, Asthma & Immunology (AAAAI) and the Centers for Disease Control and Prevention botulism clinical treatment guidelines workgroup 1, the potential for botulinum antitoxin to induce an IgE-mediated response is present, and remnants of additives in the product may themselves induce reactions in susceptible individuals.

Key Points to Consider

  • The study found that data on allergic reactions and anaphylaxis rates in botulinum antitoxin recipients were sparse and not specific to the new HBAT 1.
  • The rate of anaphylaxis to botulinum antitoxin is estimated at 1%–2%, with no reports of fatal anaphylaxis to botulinum antitoxin 1.
  • Skin testing (ST) has been used to identify patients likely to experience allergic reactions, but its predictive value is limited, and it is not practical in a mass-exposure event 1.
  • A test dose approach, where individuals with known potential risk factors for reaction are given a small dose of HBAT followed by the full dose if no reaction occurs, may be prudent to minimize the risk of severe anaphylaxis 1.

Management of Urticaria

If urticaria develops after Botox, patients should seek medical attention promptly. Treatment typically includes antihistamines, and in severe cases, corticosteroids or epinephrine may be necessary. Patients with a history of allergic reactions to Botox should inform their healthcare provider before treatment and may need to consider alternative treatments.

Prevention

Given the potential for allergic reactions, it is essential to establish standardized reporting of adverse immune-mediated reactions to antitoxin, allowing for more accurate assessment of the frequency and risk factors for adverse reactions 1. Additionally, patients with known risk factors for reaction, such as allergies to horse, horse serum, or horse products, should be closely monitored and considered for alternative treatments.

From the FDA Drug Label

  1. 4 Hypersensitivity Reactions Serious and/or immediate hypersensitivity reactions have been reported for botulinum toxin products. These reactions include anaphylaxis, serum sickness, urticaria, soft tissue edema, and dyspnea.

Yes, Botox injections can cause urticaria, as stated in the hypersensitivity reactions section of the drug label 2.

From the Research

Botox Injections and Urticaria

  • Botox injections have been associated with various adverse effects, including urticaria-like hypersensitivity reactions 3.
  • A case report described a 35-year-old woman who developed urticaria-like symptoms after receiving botulinum toxin serotype A (CBTX-A) injections, which resolved within 24 hours after administration of antihistamines 3.
  • Another case report documented a patient who experienced anaphylaxis after botulinum toxin type A injection, with symptoms suggestive of angio-oedema and anaphylaxis developing about 5 minutes after injection 4.
  • While urticaria is not a commonly reported side effect of Botox injections, these cases highlight the potential for hypersensitivity reactions to occur 3, 4.
  • Other studies have reported various adverse effects associated with Botox injections, including erythema, oedema, pain, ptosis of eyelid or brow, and ecchymosis, but urticaria is not specifically mentioned as a common side effect 5, 6, 7.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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