Long-Acting Beta-Agonists and Food Allergy Testing in Children with Asthma: New Insights

Food allergies are a growing concern among children and adolescents, with oral food challenges (OFCs) serving as the gold standard for diagnosis. These tests involve controlled exposure to suspected allergens under medical supervision to confirm or rule out IgE-mediated allergic reactions. Although OFCs are generally safe, severe allergic responses can occur, particularly in individuals with poorly controlled asthma. Historically, clinicians have recommended withholding long-acting beta-agonists (LABAs) for at least eight hours before an OFC. However, recent research suggests this precaution may not be necessary and that continuing asthma control medications could actually improve safety.

Understanding Oral Food Challenges and Asthma

OFCs are essential for accurately diagnosing food allergies. They allow clinicians to observe allergic reactions in a controlled environment and make informed recommendations about dietary restrictions. Severe reactions during these tests are rare, but certain factors, such as uncontrolled asthma, age in the second or third decade of life, and reactions occurring outside a medical setting, can increase risk.

Asthma management is critical in this context. For children with both asthma and food allergies, maintaining optimal asthma control is necessary to minimize complications during OFCs. Traditional guidance has suggested pausing LABA therapy before testing. This recommendation originated from early studies showing prolonged bronchodilator effects of drugs like salmeterol, which could mask early respiratory symptoms during a challenge.

LABAs and Asthma Control

Long-acting beta-agonists are commonly prescribed alongside inhaled corticosteroids (ICS) to manage moderate to severe asthma. These medications relax airway muscles and reduce the likelihood of asthma attacks. While short-acting beta-agonists provide quick relief, LABAs offer extended protection against bronchoconstriction, lasting up to twelve hours in some cases. For many children, the addition of a LABA improves asthma control and reduces exacerbation frequency.

However, this improvement creates a dilemma for OFCs. Withholding LABA therapy might unmask asthma symptoms and increase risk during testing, while continuing the medication could theoretically alter the test’s sensitivity. Until recently, the clinical impact of continuing LABA therapy during OFCs was largely unknown.

The Study: LABA Use and Oral Food Challenge Reactions

A recent study published in the Annals of Allergy, Asthma & Immunology examined whether LABA use affected the severity of reactions during OFCs in children with asthma. Researchers retrospectively reviewed 108 OFCs conducted on 91 patients aged 22 years or younger between 2017 and 2023. Patients were treated either with ICS alone or a combination of ICS and LABA, and their asthma was generally well controlled according to standardized guidelines.

The primary goal was to compare reaction severity between children on ICS alone and those on ICS/LABA therapy. Reaction severity was measured using the Consortium for Food Allergy Research (CoFAR) Grading Scale, while secondary outcomes included the need for epinephrine and occurrence of wheezing.

Key Findings

The study revealed several important findings:

• Reaction Severity: Most reactions in both groups were mild to moderate (CoFAR grades 2 or 3). There were no fatalities, and the highest grade reactions were rare.
• Epinephrine Use: Slightly more children on ICS/LABA required epinephrine (57.1%) compared to ICS-only patients (42.4%), but this difference was not statistically significant. Very few children needed three or more doses.
• Wheezing and Respiratory Symptoms: Lower respiratory symptoms were uncommon in both groups, with no significant differences observed.
• Overall Safety: LABA use did not appear to increase the severity of allergic reactions during OFCs, suggesting that withholding LABAs may not be necessary in well-controlled asthma.

These results challenge the longstanding practice of routinely withholding LABAs before OFCs. Instead, the study supports a more nuanced approach where maintaining good asthma control may outweigh the potential theoretical risks of continuing LABA therapy during testing.

Clinical Implications

For clinicians managing pediatric patients with both asthma and food allergies, these findings have several practical implications:

1. Prioritize Asthma Control: Well-controlled asthma is essential for reducing the risk of severe reactions during OFCs. Withholding effective controller therapy could inadvertently increase risk.
2. Individualized Approach: Rather than adhering strictly to a blanket guideline, healthcare providers should consider each patient’s asthma control, the severity of previous reactions, and overall risk profile.
3. Shared Decision Making: Discussing the potential benefits and risks of continuing or withholding LABAs with families can help guide safer testing practices.
4. SMART Therapy Considerations: Single maintenance and reliever therapy (SMART) regimens, which combine LABAs and ICS, are becoming more common. Findings from this study support the feasibility of performing OFCs without interrupting such therapies.

Limitations of the Study

While the study provides valuable insights, several limitations should be noted:

• Retrospective Design: The study could only establish associations, not causation.
• Medication Adherence: Actual adherence to prescribed therapies could not be confirmed, though nonadherence likely affected both groups similarly.
• Sample Size: A larger, prospective study is needed to validate these findings and assess whether withholding LABAs would significantly alter OFC outcomes.

Recommendations for Practice

Until more definitive evidence is available, clinicians might consider the following strategies:

• Continue LABAs When Beneficial: If a patient’s asthma is well controlled with LABA therapy, continuing medication may help reduce the risk of severe reactions.
• Monitor Carefully During OFCs: Even with well-controlled asthma, children should be closely monitored for early signs of allergic reactions.
• Tailor to Individual Needs: Assess each child’s asthma history, medication regimen, and allergy profile before making adjustments to therapy.

Conclusion

This study adds to a growing body of evidence suggesting that long-acting beta-agonists do not increase the severity of allergic reactions during oral food challenges. Maintaining asthma control remains the top priority, and withholding LABAs may not be necessary for all patients. Shared decision-making between clinicians and families is essential to ensure both effective asthma management and safe allergy testing. Future research should focus on larger, prospective studies to confirm these findings and guide updated clinical guidelines.

References

1. Robillard K, Crooks JL, Leung D, Hui-Beckman JW, Lanser BJ. Long-acting β-agonist (LABA) use in individuals with asthma is not associated with an increased severity of oral food challenge (OFC) reactions. Ann Allergy Asthma Immunol. 2026;127:101-110.
2. Global Initiative for Asthma. Global Strategy for Asthma Management and Prevention. 2025 Update.
3. Ullman A, Svedmyr N. Prolonged bronchodilator effect of salmeterol in adults. J Allergy Clin Immunol. 1993;91:1011–1017.
4. Derom E, et al. Comparison of salbutamol and salmeterol in methacholine-induced bronchoconstriction. Respir Med. 2000;94:1120–1126.
5. Sampson HA, et al. Guidelines for oral food challenge testing. J Allergy Clin Immunol. 2009;123:139–145.
6. PRACTALL Consensus Report on Allergy Testing. Allergy. 2009;64:1–15.
7. CoFAR Grading Scale for Systemic Allergic Reactions v3.0.
8. Global Initiative for Asthma, Controller Medication Guidelines. 2025.

Disclaimer

This blog is intended for informational purposes only and should not replace professional medical advice. Always consult a licensed healthcare provider for guidance on managing asthma or performing oral food challenges. Individual patient factors may influence the safety and appropriateness of specific treatments or testing protocols.