TOPLINE:

Birch rust spores, prevalent in autumn, were possibly associated with allergic airway symptoms including rhinitis, conjunctivitis, and asthma in susceptible individuals. The study revealed that 76.9% of tested patients had specific immunoglobulin E reactivity to birch rust spores, whereas control individuals remained symptom-free.

METHODOLOGY:

• Researchers conducted a pilot study to investigate whether an association exists between exposure to birch rust spores and allergic airway symptoms in autumn — a period when levels of other aeroallergens are minimal.
• They included 31 patients with clinical symptoms of allergic airway disease (64.5% women) during birch pollen season and compared them with 17 control individuals without symptoms or a history of allergy (70.6% women).
• Symptoms were classified as total allergic symptoms, rhinitis, conjunctivitis, or asthma, and severity was assessed using a visual analog scale (VAS).
• The annual mean concentration of birch rust spores was 1504 spores per m³ of air (2004-2023).

TAKEAWAY:

• A positive but nonsignificant association between symptom severity and amount of birch rust spores was observed.
• Patients exhibited significantly higher mean VAS scores across all symptom categories than control individuals during spore season (P < .001).
• Among the 13 patients tested, 76.9% had specific immunoglobulin E reactivity to birch rust spores, whereas all five patients who underwent skin prick testing had positive reactions.

IN PRACTICE:

“Our findings indicate that BR [birch rust] spores may function as aeroallergens and represent an underrecognized source of seasonal allergic airway symptoms in autumn,” the authors wrote. 

SOURCE:

Randi Falnes Olsen, MD, with the University Hospital of North Norway in Tromsø, Norway, was the corresponding author of the study, which was published online on November 6 in The Journal of Allergy and Clinical Immunology: Global.

LIMITATIONS:

This study was limited by the small sample size and the lack of standardized extracts for testing as birch rust is not yet medically recognized as an allergen. Additionally, individual-level exposure to birch rust spores could not be measured directly as regional spore counts may not have reflected personal exposure due to differences in activities, locations, and microenvironments.

DISCLOSURES:

This study was funded by the Northern Norway Regional Health Authority; the University Hospital of North Norway; a research fund from the Norwegian Asthma and Allergy Association; a medical research fund from the Odd Berg Group; and the Ministry of Higher Education and Research, Luxembourg. The authors declared having no conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.