<s>[INST] I was in a hot tub for about 45 minutes.  When I got out I had hives from my midsection to my feet.  My throat started to close up - scary but didn't affect my breathing.  Felt like cold-induced asthma which I occasionally get when I exercise in the cold.   I'm a 61 yr old woman in excellent health.   Normal breathing resumed in about 20 minutes, hives are mostly gone, but a few remain.   What's up with that?  Might it be the chemicals in the hot tub?  Thanks. [/INST] Hello,Welcome to HCM,You may be having allergy to the detergents you used in the tub, that why the hives are predominately over the immersed part of the body.As your symptoms are coming down nothing to worry. But you should be careful regarding this in future, identify the chemical responsible for the hives and try to avoid that.All the symptoms which you had are the classical effects of allergic reaction.Thank you. </s>