Was in the sun, used sunblock, didnt burn but my stomach and back developed a rash in areas that were exposed to the sun. itchy!what is this? why? three days, still there. skin is normal were the straps were. its not the sunblock. arms/legs fine?

Photo-activated dermatitis is a term applied to a poorly understood set of skin reactions limited to sun exposed areas. Some antibiotics that are otherwise not causing a rash may trigger this response. There are other poorly understood triggering factors that may be contained in foods you consume. In most cases the rash resolves over time. Any progression or addition of symptoms should be reported