Hi
Thanks for writing to the forum!
Have you changed the type of work too? What do you do? Certain occupations are linked to allergies due to dust, pollen, fungus, molds (as in Air conditioners), zinc, asbestos, lead, tin etc. An allergy panel should be done for this. It appears that warm and humid atmosphere suits you. Warm and dry or cold and dry climate harms you. Maybe you should try steam inhalation twice a day until your system gets acclimatized to the new weather.
Hope this helps. It is difficult to comment beyond this at this stage. Please let me know if there is any thing else and do keep me posted. Take care!
I would suggest having an allergy test (skin-*****) test done to determine if it's allergy-related (particularly pollen, dust, and mold). But you mentioned that anti-histamines didn't help so that may not be the problem.
My other thought is that it could be caused by a fungus, not necessarily a mold-allergy, but just irritation from the mold or fungus. Is there a lot of industrial pollution in the area? It could be air pollutants that your body isn't used to.