The impacts of a changing climate on human health are becoming increasingly apparent. Researchers are now exploring whether extreme heat and cold could influence the development of allergic disease, including food allergy, by disrupting the protective barriers that help determine how our bodies encounter and respond to allergens.
A recent review examines temperature extremes through the lens of the epithelial barrier theory, which proposes that damage to the protective surfaces of the skin, airways and gastrointestinal tract can contribute to inflammation, changes in the microbiome and dysfunctional immune responses. Past research into the theory has often focused on chemical pollutants and other modern environmental exposures. The authors argue that extreme heat and cold should also be considered potential contributors to barrier dysfunction.
Temperature extremes can affect the proteins that maintain tight junctions between epithelial cells, while promoting oxidative and cellular stress, inflammation and cell death. Together, these changes may make epithelial surfaces more permeable and potentially increase susceptibility to allergens, pollutants and pathogens.
Climatic temperature extremes rarely occur in isolation. Heatwaves, drought, floods and wildfires can coincide with changes in humidity, ultraviolet radiation, smoke and pollution, while affecting microbial and particulate contamination of food and water. Such combined exposures may further influence epithelial barrier health and immune regulation.
As climatic temperature extremes become more frequent, understanding these interactions could help determine how changing environmental conditions may influence allergen exposure and susceptibility.
Reference: Ogulur. et al. Extreme temperatures and the epithelial barrier theory. Semin Immunopathol 48, 22 (2026). DOI: 10.1007/s00281-026-01087-8. Available with Open Access here.
