Hi Mark, I was first dx as having chronic idiopathic urticaria. Doctors could find no reason for it and I have it everyday and they come in big wheals that grow in size and join together to form bigger ones. 2 years later, I read about cold urticaria and realise that I also have that because I broke out whenever I go somewhere cold. I live in the tropicals and weather is warm and sunny usually. But I am not free from the triggers of cold! So don't think that summer means trigger-free time!
If you swim, please do not swim alone as this may trigger a serious anaphylactic reaction and is life-threatening. Ask your dr for an epi-pen which will help with the swelling, hives, breathing until you can get to the hospital.
Shopping centres are a big problem in my place, because of the air-con; it seems everywhere public indoors has air-con and that triggers my cold urt. Rainy days are bad for me too.
Some cold urt sufferers develops hives when they come in direct contact with cold or upon getting into cold environment while some gets the hives on re-warming of the body after in a cold environment.
Anyone can develop urticaria or chronic urticaria in any point of their life even though they have no history of any allergies when young. I got this in my teens and have this for 8 years. I had a period where I got mild 'remission' where I have very few attacks. But that period didn't last long and it's back.
Taking antihistamines can help control the hives. Some might need 1 while others need a combination of antihistamines to find good relieve and control of their urticaria. Other than medication, avoiding your trigger is important. Ever since I found out cold was my trigger, I bring a jacket and extra antihistamines along when I head outdoors. However sometimes even with the jacket, I still do break out.
Good luck to you!