Eczema

My son had that I took him to the doctors and it turns out it was eczema

Looks like allergic reaction to me

Looks like eczema. My son gets it try using aveeno. My son has sensitive skin so he can't use any other soaps or creams.

Looks like eczema. My son has had it since about 4 months old and that's what it looks like when it first starts for him.

Looks like Eczema, my daughter and son both have it.

Has he had a fever recently? Looks like roseola to me.

Looks like a heat rash.

Rashes are very common with little ones as they are so sensitive but if call his dr and have him checked just to make sure ?

It could be your laundry detergent, but my friend's baby started getting baby eczema around 5 months. I dont mean to scare you or anything but maybe get it checked by a doctor of it doesn't clear up.