I recently developed strep throat and around the first day I had it I was in a pool and I broke out in hives all over my waist, knees, arms, and thighs. (I’m a swimmer and rarely go a week without being in a pool and this has never happened before.) The s

Drug reaction. I presume that you were given an antibiotic for your strep throat. If this is the first time you took this kind of abx, you may develop an allergy to it in about 10 days. However if the hives occur only when you are in water, it is called aquagenic urticaria for which pre-medication with an antihistamine may help. Note that if cold water is the issue , you need to see an allergist.