Rash on 11 month old

Have any of your babies had a rash like this? He woke up with it this morning. It’s strictly only on his stomach and a little on his chest. It’s not bothering him at all and he has no other symptoms. I did start using a different laundry detergent 2 weeks ago but I figured that would be more of an immediate reaction and would effect his whole body. We’ve also been giving him some cow milk here and he’s had no other reaction to any of the other dairy he’s had since he’s been 6 months.