cholinergic urticaria

what causes cholinergic urticaria?  food, allergy, pollen, climate, ect..........?  ive been to many dermatologists and all have told me that they cannot determine what is causing me to have this allergy?  can someone please tell me.  rsvp.  thank you. 

This is just my experience having gone to three doctors , two allergists and one dermotologist.. All told me it is histamines in my stomach going haywire. But they do not know what is causing it.. I wish i did know but i have done done food journals, vitamins , meds all of it and cant figure it out.. I have taken xolair shots for a year and that is the only thing giving me relief but i still have outbreaks here and there and they dont last long but come on for no reason i can figure out.. I hope you can figure out where yours are coming from but i doubt i will ever find out why i have them

I have Homeopathic treatment successful in my case where I had sever anaphylactic type urticaria.Epipen and prednisolones have much side effects on a long term.Meanwhile have an allergy test done to find out the exact reason and avoid that reason if at all possible,

Irregular thyroid functions are the basic reasons I felt