Why your allergies might get worse the more you're exposed
October 21, 2026
Summarised by Centrist
Scientists have discovered that nerve cells may develop a kind of memory of allergens, helping explain why repeated exposure to pollen, dust mites and other everyday substances can make allergic reactions worse over time.
Researchers at the Ragon Institute of Mass General Brigham, MIT and Harvard University found that sensory neurons, the nerve cells responsible for sensations such as touch and itching, play an unexpected role in developing allergies.
"The hypothesis was just: What if the neurons are developing a 'memory' of this allergen?" said immunologist Caroline Sokol.
In experiments involving mice, researchers exposed the animals to substances including dust mite allergens and papain, a compound derived from papaya.
They discovered that repeated exposure left the energy-producing structures inside nerve cells in a
heightened state of alert, triggering increasingly strong immune responses and more severe itching.
Surprisingly, the effect was not limited to the original allergen. Mice exposed to papain subsequently reacted more strongly to dust mites and mould, suggesting the mechanism might help explain why people develop multiple allergies.
The findings, published in the journal Cell, could eventually lead to treatments that target the underlying process rather than simply relieving symptoms.
Researchers have already identified a protein involved in this nerve-cell response, although the findings are currently limited to animal experiments involving skin inflammation and itching.
Sokol hopes further research will establish whether the process can be reversed.
"Can we reverse it?" she asked.
For allergy sufferers, that could eventually mean something more than avoiding pollen or reaching for another antihistamine.
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