Why Do Rainy Arizona Days Make Allergy Symptoms Worse?

By Nicholas Gerbis
Published: Thursday, December 26, 2019 - 1:07pm
Updated: Friday, December 27, 2019 - 8:19am

Bridget Dowd/KJZZ
Tempe is greeted with rain on Dec. 25, 2019.

Why do rainy days seem to worsen symptoms for some allergy sufferers? Changes in barometric pressure or humidity bear part of the blame.

But allergy and asthma expert Dr. Matthew Rank of Mayo Clinic says Arizona's unique environment also plays a role.

"There's a long timeframe when allergens can be present because the ground doesn't freeze like it would in the East or the Midwest. So, throughout the year, almost every time of the year, we can detect some allergens in the air."

Desert plants tend to proliferate and release pollen during wet periods, and rainfall can break up larger spores and pollens into tinier pieces that more readily penetrate into the nose, eyes or lower airways.

Mold spores are currently the chief allergen in circulation.