When Debbie Feit travels, she knows an unwelcome guest is likely to follow her home -- a sinus infection. Feit, 37, who lives near Detroit and has long suffered from asthma and allergies, attributes the inevitable infections to the conditions she encounters while traveling. Recirculated air in planes, stale-smelling hotel rooms and allergens that irritate her respiratory system, all tend to exacerbate symptoms and leave her vulnerable to infection.

“Things go kind of kablooey. I have constant congestion and sneezing. It takes away from the fun and relaxation—or my productivity if I’m traveling for business—of the trip.” Traveling presents many challenges to more than 50 million Americans who suffer from allergies, asthma and other environmental sensitivities. And it may be the very place we think of as our home away from home that causes the most discomfort.

“Hotels are notoriously problematic because they move a lot of people and dogs and cats and foods, things that wind up being allergens to many people,” says Nancy Sander, president of allergy & Asthma Network Mothers of Asthmatics. “There’s just a lot of volume.”

These days, in addition to offering nonsmoking rooms, “hotels are attempting to provide more healthy environments and cleaner rooms,” says Sander, who suffers from asthma herself.