Hello, Your urticaria may have been triggered by an urinary tract infection, but if the symptoms of smelly urine has happened after the urticarial eruption it is generally due to either long acting antihistamines or steroids (occasionally given for bad urticaria) that tends to concentrate urine. Have plenty of water, get a urine dipstick or c/s studies and if there is evidence of an UTI, get antibiotics but continue the antihistamines until 4 weeks or at least a week after the infection has cleared as well as the itchy rash. Thanks.