I moved away from Chicago about four years ago. I now find myself returning for brief (week or so long) consulting stints.

After a few days in the city, the skin around my eyes turns red and puffy. Hydrocortizone cream helps, sort of. This never happened to me in the 14 years I lived there. I do have an allergy to a pesticide that causes this, but I've been visiting in winter and haven't been near lawns, gardens or parks.

Someone told me this may be due to becoming accustomed to a place with clean air and suddenly getting exposed to nasty air. But I've taken long trips to other polluted cities (LA, Bangkok, Hong Kong) without a problem.

Anyone else experience this? Is it the difference in air quality or something else?

If these are recent trips to Chicago, it is the dead of winter - and a cold and snowy one at that. It's highly unlikely you are experiencing the effects of outdoor airborne allergens, it more likely you are experiencing difficulties with the extremely low indoor humidity - based on recent out door temps, the process to heat the air has resulted in the indoor humidity to be as low as 3%. The comfortable level is 36 to 40%.

I'm coming from the Colorado mountains, which is drier than Chicago and just about as cold.

Point is, this has happened to me EVERY time I've been to Chicago recently and never anywhere else with similar characteristics.