In the first minute
It all begins with a mating game. Male pollen grains drift off in search of female plant parts to fertilize. Cute, except that the powdery stuff is so pervasive that you'll undoubtedly breathe it in or rub it into your eyes. If you're allergic, your body makes antibodies called IgE. Pollen launches them into action.
IgE antibodies coat the outside of mast cells, which are part of the immune system and are abundant in the nose, throat, eyes, skin, and lungs. As pollen binds to IgE, mast cells release a trove of chemicals, the most famous of which is histamine, the marine corps of allergy warfare.
Mast cells continue to fire off, releasing more and more histamine. Problem is, the tricky chemical can be tough on your body.
After five minutes
Histamine has set your mucous membranes into overdrive—by now you've said hello to sneezing, a runny nose, and watery eyes.
Your airways may begin to constrict, leaving you short of breath or with a tight feeling in your chest. Histamine may also make your throat itch.
As long as you're exposed to pollen, the miserable cycle keeps going—unless you take an antihistamine. It's best to pop one stat (or better yet, in anticipation of an attack), because mast cells are popping off like crazy.
In the next few hours
The mast cells release a second offensive wave of immune mediators, which turn your dripping, sneezing nose into a stopped-up disaster. An antihistamine will be less effective now.
If you're very allergic, your eyelids might begin to swell.
After a few days
If you're still in pollen territory, mucus has set up camp in your nose and sinuses. Gone are the days of suffering in silence with a tissue—the phlegm in your throat makes you cough and snore. (Using a prescription nasal steroid, such as Flonase or Nasonex, before this point might have quieted the reaction.)
Your respiratory system, normally able to sweep out germs with its tiny hairlike cilia, is now gridlocked with congestion, creating an ideal bacterial breeding ground. You're at higher risk for a sinus or ear infection. If you have seasonal asthma, you could develop a chronic cough. Only a visit to a doctor, who can give you a stronger treatment, can quell your advanced allergic reaction.
After a few months
It's fall—you're home free! Unless, of course, you're allergic to ragweed...
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