Rash on baby?

maria

My 8 month old has has this rash for the last two weeks. It’s on his back and chest. Sometimes it’s worse than other times but it doesn’t seem to bother him at all. Does it look like a food allergy rash or an allergy to detergent. He did have this rash around the time he had rsv so I was thinking it was a viral rash but it never went away completely.