People who experience runny noses during allergy season may have different molds in their noses than those who do not.

That’s according to a new study in the journal Frontiers in MicrobiologyPeople who get allergic rhinitis – also known as hay fever – have a greater variety of fungal species in their noses.

This means that future treatments for runny nose during allergy season could target specific types of mold.

“We showed that allergic rhinitis samples showed significantly higher fungal diversity and a different fungal community structure compared to healthy controls,” study co-author Luís Delgado, a researcher at the University of Porto in Portugal, said in a statement.

“This may indicate that allergic rhinitis increases the diversity and changes the composition of the microbiome of the upper respiratory tract.”

Hay fever is an allergic reaction to airborne allergens that cause inflammation and irritation of the nasal passages. It occurs when the immune system overreacts to substances that are usually harmless, such as pollen, dust mites, animal dander, or mold spores.

Symptoms of hay fever include sneezing, a runny or stuffy nose, watery or red eyes, and an itchy nose and throat. Hay fever is also often seen in people with asthma.

In the paper, the researchers describe how they sampled the nasal microbiome of 214 people. Of these, 155 had both allergic rhinitis and asthma, while 47 had only allergic rhinitis and 12 had only asthma.

The researchers took swabs from two different areas of the participants’ noses and sequenced the fungal DNA to determine the species of fungi present.

They found that the most frequently observed fungi came from the Ascomycota and Basidiomycota families, with 14 genera across the two families dominating the participants’ fungal microbiomes.

“Among these dominant genera, we detected common fungi that have been recognized as allergenic or opportunistic pathogenic fungi in humans,” said Delgado. “This suggests that the nasal cavity is a major reservoir of fungi that could be involved in allergic rhinitis and asthma.”

They also found that people with hay fever and asthma had more diverse fungal microbiomes than healthy participants.

“Addressing some of these clinical variables would be an interesting continuation of our study if we could get the appropriate funding,” Delgado said. “If we can’t go any further at this stage, key data and hypotheses are published here for others to replicate and finally link the lab bench to the clinic.”

Reference

Perez-Losada, M. et al. (2024) The nasal mycobiome of individuals with allergic rhinitis and asthma differs from healthy controls in composition, structure and function, Frontiers in Microbiology. DOI: 10.3389/fmicb.2024.1464257