In need of help navigating life with diabetes? You can always Ask D’Mine! Yep, our weekly Q&A column by veteran type 1 and diabetes author Wil Dubois is here for you.

This time of year often brings seasonal allergies — causing watery eyes, stuffy nose, and more pesky allergy symptoms. Today, Wil takes on a question about how those allergies may impact diabetes control.

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Becky, type 2 from Wisconsin, asks: What effects do seasonal allergies have on blood sugars?


Wil@Ask D’Mine answers: Apparently, none. Yeah, that came as a surprise to me, too. I figured anyone suffering from the runny nose, sneezing, itchy eyes, sore throat, coughing, and fatigue of hay fever (more correctly allergic rhinitis) would be suffering a blood sugar disaster—but all the experts say otherwise. And what little science there is to be found on the subject backs them up, although the primary study on the relationship between “hay fever” and blood sugar—you’d better sit down—is from 1936!  

Talk about being the final word on a subject.

The researchers—Doctors MacQuiddy and McIntrye, along with Harvard grad Mr. Koser—wrote in the July 1936 edition of The Journal of Allergy and Clinical Immunology that they found no “significant difference between the normal and the allergic individual” both in regard to their fasting BGs, or in response to a 100-gram dextrose hit.

Of course, the study subjects didn’t have diabetes. Have there been no studies of seasonal allergy in persons with diabetes? Not as such, although interestingly, I did find one large study from Korea that showed that people with metabolic syndrome are less likely to suffer allergic rhinitis than “healthy” folks, what medical researchers like to call an inverse relationship. How about that? Finally, a benefit from having some sort of blood sugar problem! Of course, metabolic syndrome isn’t diabetes, but it’s only one off-ramp away.

And while hay fever doesn’t seem to raise blood sugar, apparently, high blood sugar can lower hay fever. Another large study, published in the journal Diabetes Care, found that PWDs with higher blood sugars had a lower prevalence of hay fever. Not that I’m advocating leaving your blood sugar high to avoid hay fever, but I found that fascinating.

Meanwhile, in the trenches, things are more complex, as is often the case. In diabetes community forums there seems to be a mixed bag of anecdotal responses, with some people reporting that their sugar levels are unaffected even though they are suffering tremendously from their hay fever symptoms, while others are reporting their BGs are “off the chart” even when suffering only mild hay fever.

Could the body’s response be that variable from person to person, or is there something else going on here?

The first thing to consider is that when you feel like crap, it’s hard to stay focused on your diabetes. So no doubt, some folks dealing with the runny nose, sneezing, itchy eyes, sore throat, coughing, and fatigue of hay fever (or for others, congestion and pain) probably aren’t as focused on their diabetes care as they need to be to keep their blood sugar in target range.

Oh, and speaking of care and treatment, how is hay fever treated, and can that have an impact on blood sugar?

In ascending order hay fever treatments are: antihistamines, decongestants, and finally steroids.

The common wisdom is that antihistamines—which are the premier meds for reversing allergy symptoms—don’t have a direct impact on blood sugar. But they do make some folks sleepy, so if you dose up, you might snooze through taking your diabetes meds. Or as Certified Diabetes Educator Amy Campbell points out, you might be less alert to the symptoms of a low blood sugar should you have the bad luck to have one at this time. And while the allergic reaction itself isn’t raising blood sugar like most other illnesses, it is most likely interfering with the joy of eating, so that raises the risk of a low blood sugar as well. 

Decongestants, the second line of defense during many hay fever attacks, is another story altogether. A number of them do have the side effect of rising blood sugar.

And of course, really severe allergy reactions may require a steroid, a family of meds notorious for sending blood sugar through the roof. Be aware that some over-the-counter nasal sprays have steroids, so be sure to check the label before you buy!

So what to do? While hay fever itself is harmless to our blood sugar, the treatments for it can raise our glucose.

Well… can we talk condoms? Don’t freak out. It’s just an analogy. Condoms won’t help reduce hay fever, but just like condoms can prevent unwanted pregnancies and STDs (which are always unwanted), there are things you can do to prevent hay fever before it strikes. 

I probably should have mentioned this earlier, but hay fever happens when the body’s immune system over-reacts to allergens in the air. These allergens can be pollen from trees, grasses, and weeds; dust mites; pet dander; and sometimes even mold spores. So avoiding hay fever means avoiding, or minimizing, contact with these allergens.

To do that, the Mayo Clinic recommends that allergy sufferers stay indoors on windy days, presumably because this is when there’s the most pollen in the air. They say the best allergy avoidance exercise time is right after a rain storm when the air is washed clean and pollens are not easily stirred from the ground. Speaking of washing, they advise taking a quick shower after coming in from outdoors to rinse pollen from your hair and skin, changing and washing clothes after you’ve been outside, and fer God’s sake don’t hang your clothes on an outdoor laundry line—that just makes them pollen magnets. Oh, and in the best advice ever: Mayo says seasonal allergy sufferers should “delegate lawn mowing.”

Honey, I can’t mow the lawn, my allergic rhinitis is flaring up…

Other tips from Hayfeverologists are to sleep with a HEPA filter in your bedroom, and to track local pollen counts through local news outlets or weather forecasts and proactively take meds when high counts are forecast, rather than waiting until you start feeling like hell.

Of course, then we’re right back to the hay fever treatment messin’ with your blood sugar — but at least if you’re suffering less, you’ll be more focused on your diabetes.


This is not a medical advice column. We are PWDs freely and openly sharing the wisdom of our collected experiences — our been-there-done-that knowledge from the trenches. Bottom Line: You still need the guidance and care of a licensed medical professional.