We have just spent 8 days trying to figure out why my 3 YO had a crazy rash (red cheeks and very very mottled skin) and high fevers of almost 105. (scary) After tons of bloodwork including negative parvovirus, an ID doctor visit and a cardiology exam for Kawasaki disease the cardiologist said "has anyone mentioned drug fever to you? I think Bactrim is one of those drugs that can cause that." Upon scanning the internet have found that every scary symptom DD had could be caused by Bactrim. Since I stopped it fever vanished. Yikes, sharing this in case others have these symptoms. DD had been on ZIth/Bactrim combo for 10-12 days before this started.