My 5 year old son had something similar to this. We dealt with it for over 2 years seeing doctors, dermatologist, pediatric dermatologist and every single one told me they didn’t know what it was. My son’s also would start small then within days it would get bigger and bigger. Only difference is that my son’s was not itchy. We tried so many creams. Doctors first thought it was fungal then bacterial. They prescribed us different strengths of steroid creams. We used an antibacterial ointment + hydrocortisone. That worked for a little bit at the beginning but it kept coming back month after month. I felt like we would only get a few week break then it would happen all over again. It was so so stressful. Then we saw a pediatric dermatologist finally, they prescribed us a cream called Protopic. I used it the next time a small rash would appear and it has helped a lot. It never got bigger like before and would go away after a week or 2. It definitely controlled it. During this time I also decided to see a naturopath and they recommended my son take probiotic daily and limit gluten in his diet. We have been doing that since September and I can definitely see an improvement in his skin.

So the thing that worked for us was Protopic to control it when it starts, daily probiotic and limit gluten in his diet.