It's also possible for them to go away again. My mother had a wide variety of allergies over her life, and some stayed a long time and some only a little while.
Look at what other things are outgassing or giving off pollen or spores or smells in the area. The thing is, when one thing starts to irritate you, others jump in that you don't expect. My allergies here in Maryland are much different than when I was in New York state -- different climate, different local pollutants, much more humidity.
ETA: When we had Simba the Magnificent, the 18-lb Maine Coon cat with the thick fur, I was allergic to him -- but it was *much* less when he did not eat fish. There is apparently some enzyme in cat saliva when they have to digest fish that is not there the rest of the time, and that enzyme is an allergen -- and since they lick themselves, it gets on all of them and into the dander. No fish? Much less problem.
no subject
Look at what other things are outgassing or giving off pollen or spores or smells in the area. The thing is, when one thing starts to irritate you, others jump in that you don't expect. My allergies here in Maryland are much different than when I was in New York state -- different climate, different local pollutants, much more humidity.
ETA: When we had Simba the Magnificent, the 18-lb Maine Coon cat with the thick fur, I was allergic to him -- but it was *much* less when he did not eat fish. There is apparently some enzyme in cat saliva when they have to digest fish that is not there the rest of the time, and that enzyme is an allergen -- and since they lick themselves, it gets on all of them and into the dander. No fish? Much less problem.