Does one build up a tolerance to antihistamines?

I’m not asking for medical advice, but just to clarify via back story: For many years, I did quite well on one Zyrtec daily to treat dermagraphia. Then last summer, it suddenly got much worse, and the Zyrtec alone wasn’t putting a dent in it. The doc tried a number of antihistamines, and the only thing that works is a daily combination of Zyrtec and Allegra, each at twice the recommended dose. (Dr. says this is safe.)

I’ve heard that people on antihistamines for long periods eventually find them less effective (though I was on Zyrtec, first Rx and then OTC, for 20 years), and the solution seems to be to rotate types. However, in my case, there doesn’t seem to be an effective antihistamine to rotate with the two I’m on.

So disregarding the rotation method, do people on antihistamines build up a tolerance. like people on some painkillers do? I don’t want to have to take dangerously high levels of antihistamines to keep this condition under control.

Any information would be greatly appreciated.