Different types of allergies
In my experience, people blame different things for their allergies depending on what stage of life they are in. If I see a baby or young child with allergy symptoms, the parents almost always assume it’s a food allergy. With adults, they seem far more likely to assume pollen or other environmental factors. Are they all right? No, but they aren’t necessarily wrong either. Anyone can have an allergy to anything at any time, so figuring out the culprit involves detective work, maybe an educated guess, and sometimes even a trip to the allergist for testing.
Food allergies are more common in children, so it’s not unreasonable to look to foods for the source of that itchy rash or runny nose and dark circles under the eyes. It is common, though, for parents to come in confident that food isn’t the source of the problem because “we took her off wheat and dairy and corn for a week and nothing got better.” In these cases, I have to explain that a week isn’t usually long enough to see a difference and it is possible that the child is reacting to something other than the three things they removed. I’ve seen kids with allergic reactions to bananas, apples, rice, pork, all kinds of nuts, oranges, berries, pineapple, soy, and so many more foods. Going off a random selection of foods for a short time might help, but more often than not it isn’t enough.
Of course, sometimes food isn’t the problem—or isn’t the only problem. A lot of people react to household dust, and mold in the home is the cause of many, many allergies. I have talked people through some “allergy hygiene” and had them return to tell me they didn’t think mold could have been a problem then they pulled the bed out from the wall and found mold growing behind the bed. Small leaks can be just bad enough to allow a lot of mold growth but not bad enough for you to know there’s a leak that needs fixing. In the Pacific NW, dampness is a way of life but it can allow a lot of mold and mildew growth that can cause a lot of people to be miserable.
Allergies can also be caused by environmental factors like pollution or workplace chemicals. Sometimes hobbies expose us to things that cause reactions. Cigarette or camp fire smoke, auto exhaust, or just a new shampoo or lotion can cause allergic reactions in some people. Whether you know what your allergens are or not, talking it through with your doctor can help you get to the answer.