Maybe if your mom hadn’t stopped you from eating dirt at the playground, you wouldn’t be all itchy now and runny-nosed because it’s allergy season.

It is that time of the year again, as nature sends out millions of grains of pollen, seemingly mostly into your eyeballs and nostrils.

Are you part of that select club of 3 to 5 percent of the population who experts say are severely affected by airborne allergens?

How severe? Oh, maybe like this:

As James Thurber, the celebrated humorist, is said to have complained, “I used to wake up at 4 a.m. and start sneezing, sometimes for five hours. I tried to find out what sort of allergy I had but finally came to the conclusion that it must be an allergy to consciousness.”

And guess what, pollen sufferers? It’s only going to get worse.

The allergy season is expected to last for longer stretches, because of — what else? — global warming.

Plus, pollen allergies may also affect a larger group of people as more and more of the world’s population lives in … too-hygienic a society. Yes, too clean.

“One of the ideas about why allergies seem to be increasing in the developed world is that we have all these cells that function as a defense mechanism against parasites — bad water, bad food, mosquito-borne diseases, even snake venom,” says Dr. David Robinson, a Virginia Mason Medical Center allergist.

As hygiene increases, these cells have fewer parasites to fight, but they’ve got to fight something.

They decide to fight pollens, which they do by releasing a compound called histamine, which gives us a runny nose and watery eyes to expel those pollens the cells believe are parasites.

The ‘hygiene hypothesis’

The “hygiene hypothesis” was the subject of a 1999 study comparing asthma and allergic reactions in children before and after the reunification of East and West Germany.

A Tufts Medical Center report says, “Before unification, East Germany had more children growing up on farms and in larger families than West Germany; the population also had much lower rates of allergies and asthma than West Germany.

“After unification, however, when East Germany developed a more Western culture, its rates of allergies and asthma increased to the degree that they now resemble those of West Germany.”

By the way, when you buy over-the-counter allergy medication that contains antihistamines, you’re not buying something that stops histamine production. The antihistamine simply attaches itself to the receptor sites to which the histamine would attach itself, and blocks it by having gotten there first.

As for climate change, a 2011 report by the federal Environmental Protection Agency says warmer temperatures and more rain will cause some plants to grow faster, bloom earlier and produce more pollen. And, says the EPA, we can expect “allergy seasons to begin earlier and last longer.”

That doesn’t mean a drastic change in pollen seasons.

What the EPA says “makes a lot of sense,” says Dr. Reynold Karr, a clinical professor in the University of Washington’s Division of Allergy and Infectious Diseases, and the Division of Rheumatology. “But I haven’t seen a significant change at this point.”