Hi Doctor, my concern is that my grandson has had a bad reaction possibly after taking a drug Keflex. We are told the manifestion was ERYTHEMA MULTIFLORA, possibly, the skin developed hives like skin blotches all over his body, very pronounced on the back, buttocks, down his legs , hands fingers & face. We are following up further blood tests skin & urine analysis. Do you have knowledge of reaction of Keflex in your experience. Thank you for your help . SEL.