The interplay between allergic rhinitis and COVID-19 continues to reveal surprising complexities. Novel research indicates that individuals with allergic rhinitis may experience COVID-19 differently than those without, exhibiting a lower likelihood of typical respiratory symptoms but a heightened risk of losing their sense of smell or taste, as well as developing a fever. Understanding this connection, and how treatments like sublingual immunotherapy might influence these outcomes, is becoming increasingly important as we navigate ongoing respiratory virus seasons. This research into allergic rhinitis and COVID-19 offers valuable insights for both patients, and clinicians.
A retrospective cohort study, conducted in China, examined the COVID-19 experiences of 1,368 participants. The study, published in Scientific Reports in 2026, included 746 individuals diagnosed with allergic rhinitis and 622 control subjects without allergic diseases. Researchers analyzed data collected within one month of adjustments to COVID-19 response measures, providing a snapshot of real-world experiences during a period of evolving public health strategies. Among the allergic rhinitis group, 122 were receiving sublingual immunotherapy, while 483 were not. Propensity score matching was used to ensure a fair comparison between groups.
A Dual Effect: How Allergic Rhinitis Impacts COVID-19
The study revealed a seemingly paradoxical effect of allergic rhinitis on COVID-19. Compared to individuals without allergies, those with allergic rhinitis were less likely to report traditional respiratory symptoms like cough or shortness of breath. This suggests a potential protective association, though the underlying mechanisms remain under investigation. However, the research likewise found a significantly higher risk of olfactory (smell) and gustatory (taste) dysfunction, commonly known as loss of smell and taste, among those with allergic rhinitis who contracted COVID-19. The incidence of fever was also elevated in this group. These findings, detailed in the study by Zhang Y-Y et al., suggest that allergic rhinitis may modulate the body’s immune response to the virus in complex ways.
Sublingual Immunotherapy: A Modifying Influence?
The impact of sublingual immunotherapy (SLIT), a form of allergy treatment involving placing a small dose of allergen under the tongue, further complicated the picture. Among patients with allergic rhinitis who were receiving SLIT, researchers observed a higher risk of respiratory symptoms compared to those with allergic rhinitis who were not undergoing immunotherapy. This suggests that SLIT might, in some cases, alter the way the body responds to a COVID-19 infection, potentially increasing the likelihood of respiratory involvement. Conversely, the study found that SLIT was associated with a lower risk of fever in individuals with allergic rhinitis. Notably, SLIT did not appear to significantly affect the occurrence of olfactory or gustatory dysfunction.
These observations point to the possibility that immunomodulatory treatments like SLIT can influence specific inflammatory pathways involved in both respiratory and systemic manifestations of COVID-19. The researchers hypothesize that SLIT may shift the immune response, potentially impacting the severity and presentation of the illness. Further investigation is needed to fully elucidate these mechanisms.
Clinical Implications for Managing Allergic Rhinitis During Viral Transmission
The findings have important implications for clinicians managing patients with allergic rhinitis, particularly during periods of heightened respiratory virus transmission. The study underscores the need for careful evaluation of respiratory symptoms when considering whether to continue or initiate sublingual immunotherapy in patients who may be infected with COVID-19. The altered risk of fever also warrants close monitoring and clinical assessment. Clinicians should be aware of the potential for atypical COVID-19 presentations in patients with allergic rhinitis, particularly the increased risk of losing smell or taste.
The study authors emphasize the need for further research to clarify the underlying mechanisms driving these associations and to inform personalized treatment strategies. A deeper understanding of the interplay between allergic rhinitis, immunotherapy, and viral infections could lead to more effective approaches to managing both conditions. The study, published in Front Allergy, highlights the importance of considering individual patient factors when making clinical decisions.
What Does This Mean for Patients?
For individuals with allergic rhinitis, these findings suggest that being aware of potential atypical COVID-19 symptoms – particularly loss of smell or taste – is crucial. If you experience these symptoms, even without a cough or fever, it’s important to consider testing for COVID-19 and consulting with a healthcare professional. If you are undergoing sublingual immunotherapy, discuss with your doctor whether it’s appropriate to continue treatment during periods of high viral transmission, weighing the potential benefits and risks.
The research team acknowledges that further studies are needed to confirm these findings and to explore the long-term effects of allergic rhinitis and immunotherapy on COVID-19 outcomes. Ongoing research will help refine our understanding of these complex interactions and guide clinical practice.
Disclaimer: This article provides general information and should not be considered medical advice. Always consult with a qualified healthcare professional for diagnosis and treatment of any medical condition.
The next step in understanding this complex relationship will be larger, multi-center studies to validate these findings across diverse populations. Researchers are also planning to investigate the specific immune mechanisms involved in these associations, which could pave the way for targeted therapies. Share this information with your network and continue to stay informed about the latest developments in respiratory health.
