Can Xolair (omalizumab) cause fever?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: June 25, 2025View editorial policy

Personalize

Help us tailor your experience

Which best describes you? Your choice helps us use language that's most understandable for you.

From the Guidelines

Xolair (omalizumab) can cause fever as a side effect, although the provided evidence does not directly quantify the incidence of fever as a specific adverse reaction. The available data primarily focuses on anaphylaxis and anaphylactic reactions associated with Xolair, with a reported rate of 0.09% of patients experiencing anaphylaxis 1. While fever is not explicitly mentioned in the provided studies as a common side effect, it is reasonable to consider it as part of the spectrum of hypersensitivity reactions that can occur with monoclonal antibodies like omalizumab.

Key Considerations

  • The mechanism behind potential Xolair-induced fever could involve the immune system's response to the medication, similar to how it causes anaphylaxis in some patients 1.
  • Patients experiencing fever after receiving Xolair, especially if accompanied by other symptoms like rash, difficulty breathing, or swelling, should promptly contact their healthcare provider.
  • It is crucial for healthcare providers to monitor patients closely, especially after the first few injections, due to the higher likelihood of reactions occurring during this period.
  • Management of fever might include antipyretics like acetaminophen, and the decision to continue Xolair treatment should be made on a case-by-case basis, weighing the benefits against the risks of adverse reactions. Given the potential for fever as part of a hypersensitivity reaction, it is essential for patients and healthcare providers to be vigilant for any signs of adverse reactions following Xolair administration.

From the FDA Drug Label

  1. 6 Fever, Arthralgia, and Rash In post-approval use, some patients have experienced a constellation of signs and symptoms including arthritis/arthralgia, rash, fever, and lymphadenopathy with an onset 1 to 5 days after the first or subsequent injections of XOLAIR.

Xolair can cause fever as part of a constellation of signs and symptoms that have been reported in post-approval use, including arthritis/arthralgia, rash, and lymphadenopathy, typically occurring 1 to 5 days after the first or subsequent injections of XOLAIR 2.

From the Research

Xolair and Fever

  • There is no direct evidence in the provided studies that Xolair (omalizumab) causes fever as a side effect 3, 4, 5, 6.
  • However, a study on drug-induced fever suggests that some medications can cause fever as a result of a hypersensitivity reaction, which may be a possibility with any drug, including Xolair 7.
  • The studies on Xolair focus on its effectiveness in treating allergic asthma and its effects on immunological parameters, but do not mention fever as a common side effect 3, 4, 5, 6.
  • It is possible that fever could occur as a rare or idiosyncratic reaction to Xolair, but there is no evidence to support this in the provided studies.

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.

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.