Hi there, Thank you for choosing healthcaremagic. We will try to answer your query. You mentioned that your daughter is being treated for a bladder infection with sulfameth/trimeth and now has a rash after 8 days of treatment. You have been told that it is probably hand foot and mouth. Since I don t have an image of the rash, it will be hard for me to say but I can give you some clues on to what a rash of hand foot and mouth looks like. If it is hand foot and mouth disease, she will have poor apetite from sores or ulcers in the mouth, you have to look carefully by everting her lip and looking at her gingiva, under the tongue and sides of mouth as well. It also causes blisters on the palms and soles. It s most prominent in buttocks as well. Whereas if you have seen what an allergic rash looks like, it looks like hives which causes itching and may be present all over the body including trunk. There is another reaction which is unpredictable and can happen with certain medications like sulfamethoxazole called erythema multiforme which can cause peeling of the mucus membranes and rash all over the body, this reaction can be dangerous if it is spreading and will need urgent evaluation by a physician. I would suggest you to take your daughter to her pediatrician soon for the rash especially if you are unsure if it is allergy or not and get treated accordingly. Hope this helps. Best wishes. Regards, Dr. Sumeet.