Your condition could be a physical allergy.Physical allergies are allergic reactions to cold, sunlight, heat, or minor injury.The immune system usually responds only to certain kinds of chemicals, namely proteins. However, non-proteins can trigger the same sort of response, probably by altering a protein to make it look like a target. Physical allergy refers to reactions in which a protein is not the initial inciting agent.
Heat allergies can be caused by exercise or even strong emotions in sensitive people.
nervousness raise the body temperature and can trigger this off.Some people can be allergic to their own sweat.
Water contact can cause aquagenic urticaria, presumably due to chlorine or some other trace chemical in the water, although distilled water has been known to cause this reaction.The textures of certain clothing can cause this to happen.
Removing the offending agent is the first step to treatment.
The reaction can usually be controlled with oral antihistamines, or cortisone-like drugs. Itching can be controlled with cold packs or commercial topical agents that contain menthol, camphor, eucalyptus oil, aloe, antihistamines, or cortisone preparations.
Since aquagenic urticaria and aquagenic pruritis are pretty rare, what you are most likely suffering from is cholinergic urticaria. You can research it by googling. That is what I am looking into right now.