Welcome to HCM,
might be due to some allergen, either internally or from external allergen.
Try to find out the allergen and avoid it.
External allergen might be from, soap,shampoos, clothes, scent, spray, dust, pollen bodies, some food etc.
Internal allergens might be due to worm infestation.
As you gained weight there might be possibility of having diabetes
In diabetes again chronic urticaria is common.
So consult your doctor and get investigated.
Ok and bye.