Poor Allergic Rhinitis Symptoms in Air Conditioning May Predict Greater Severity

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A new study showed that children with allergic rhinitis who experience worsening symptoms in air-conditioned environments may be more likely to have a more severe form of the condition.¹

“Our findings suggest that symptom exacerbation during air-conditioner use can predict [allergic rhinitis] severity in children,” wrote investigators, led by Yinhui Zeng, from the department of Otolaryngology, Guangzhou Women and Children’s Medical Center at Guangzhou Medical University in China.

Numerous studies have examined diagnostic biomarkers to help identify allergic rhinitis, finding people with seasonal allergies have nasal inflammation—demonstrated with increased eosinophils and neutrophils levels—and increased markers of inflammatory cell activation, such as tryptase, eosinophil protein X, and myeloperoxidase.² People with allergic rhinitis also had increased ICAM-1 expression.

Despite evidence on the biomarkers of allergic rhinitis, little data exists on the characteristics of pediatric allergic rhinitis with different severity. Some studies have identified air conditioners in the summer as a risk factor for the progression of allergic rhinitis, but other studies indicated that air conditioners protect against wheezing by decreasing outdoor allergen exposure.^3,4 Investigators sought to compare the characteristics of pediatric allergic rhinitis with different severity.

The study included 1054 children and adolescents aged 3 – 18 years (68.1% male) with allergic rhinitis who visited the Guangzhou Women and Children’s Medical Center in China between August 2015 and August 2023.¹ Children had typical nasal symptoms based on ARIA Guidelines and a positive serum-specific IgE test or skin prick test for ≥ 1 aeroallergen, such as house dust mites, cockroaches, weed pollen, fungi, cat dander, and dog dander. The study excluded children with tumors, mental disorders, asthma, and atopic dermatitis.

Children were classified by allergic rhinitis severity, with levels being mild intermittent (10.5%), mild persistent (32.2%), moderate-to-severe intermittent (8.6%), and moderate-to-severe persistent (48.7%). The severity was determined by the total nasal symptom score, evaluating nasal itchiness, nasal congestion, sneezing, and rhinorrhea on a 3-point scale. A score from 0 – 4 indicated mild allergic rhinitis and a score from 4 – 12 indicated moderate-to-severe allergic rhinitis.

Children completed a questionnaire on demographic information, including age, gender, height, weight, family history, dietary habits, and living environment. The Phadia UniCap 100 analyzer measured the serum total IgE and allergen-specific IgE, and blood cells were analyzed using an automatic hematology analyzer.

Children with different allergic rhinitis severity levels had no significant differences in the demographic characteristics of age, gender, and BMI. The groups also had no significant differences in feeding patterns, dietary habits, outdoor activity time, total IgE, eosinophil count, and eosinophil percentage. When examining environmental factors, patients across the severity levels had no significant differences in living environment, region, pet, plush toy ownership, smoking history, air conditioning usage frequency, bedding cleaning frequency, bedroom occupancy time, and carpet ownership.

A multivariate regression analysis revealed participants with moderate-to-severe persistent allergic rhinitis were more likely to have worsened symptoms when using air conditioning. This suggested symptom exacerbation when using air conditioning was linked to disease severity. The study also showed that more participants with moderate-to-severe persistent allergic rhinitis had a family history of the condition.

Investigators wrote the study was limited by its single-center design and its focus on mite-allergic children which limits the generalizability of the findings to regions with more pollen or other allergens. They noted that since mites are a major allergen in southern China, air conditioning may expose children with allergic rhinitis to greater mite levels.

“We found that the exacerbation of symptoms during air-conditioner use was the only factor associated with [allergic rhinitis] severity,” investigators concluded. “…doctors and parents should closely monitor children with [allergic rhinitis] whose symptoms worsen when using an air-conditioner, as this may indicate a higher initial severity.”

References

1. ^{Zeng Y, Lin T, Xie W, Gao S, Zeng Q, Luo X, Liu W. Characteristics of Pediatric Allergic Rhinitis With Different Disease Severity. Mediators Inflamm. 2025 Jan 16;2025:5553039. doi: 10.1155/mi/5553039. PMCID: PMC11756943.}
2. ^{Canonica GW, Compalati E. Minimal persistent inflammation in allergic rhinitis: implications for current treatment strategies. Clin Exp Immunol. 2009 Dec;158(3):260-71. doi: 10.1111/j.1365-2249.2009.04017.x. Epub 2009 Aug 25. PMID: 19765020; PMCID: PMC2792821.}
3. ^{Sun Y, Hou J, Sheng Y, Kong X, Weschler LB, Sundell J. Modern life makes children allergic. A cross-sectional study: associations of home environment and lifestyles with asthma and allergy among children in Tianjin region, China. Int Arch Occup Environ Health. 2019 May;92(4):587-598. doi: 10.1007/s00420-018-1395-3. Epub 2019 Jan 9. PMID: 30627853.}
4. ^{Huang S., Garshick E., Weschler L. B., et al. Home Environmental and Lifestyle Factors Associated With Asthma, Rhinitis and Wheeze in Children in Beijing, China. Environmental Pollution . 2020;256:p. 113426.}