Pool allergy

[missribbit]

I joined the YMCA and began water aerobics in September of last year. I went twice a week in the warm water pool. In February, I got out of the pool as usual and went to take a shower and my back was itching. I washed thoroughly as usual and drove home. By the time I got home I was ready to crawl out of my skin. My back was broken out in a rash. I went to my doctor the next day and he told me I had an allergic reaction to something. I tried the pool again the next week and the same thing happened. My back looked like I was a burn victim. I have had skin patch testing done and I am not allergic to the water in the pool nor any detergents. I have talked to the YMCA and they have not changed the pool chemicals since I started there. Before doing the patch testing, the doctor performed a thyroid test and found that my TSH levels were high enough for medicine, but once on the medicine my thyroid level was to low. So I don't take thyroid medicine any more. It didn't do any good at relieving the allergic reaction to the pool either. Any advice, any direction I should start researching, or any doctors I can contact would be appreciated.