This is my best friends son. Any idea what this is? She thought baby acne at first but it just keeps spreading.

Looks like a form of cradle cap. My daughter had the same thing. It's surprising because I thought cradle cap was limited to the scalp, but its not. Bathe and shampoo with head and shoulders is what our pediatrician told us. It went away fairly quick.

Could be a heat rash, reaction to soaps or lotion or could be a viral rash.

Best to get the baby checked out.

Looks like an allergy. Call pediatrician.

Def allergy!

My son has an allergy to bananas. That looks similar to the rash he got...

One time I thought he was exposed to bananas at school and brought him to the doctors. .. Thst time they diagnosed hum with 5ths disease..

Was odd but they said it was common...

Either way I would suggest to check in with Pedi... let us know. Goodluck sorry for Lil one..

I told her I thought an allergic reaction too. She's going to take him in tomorrow. Thanks so much!!

This looks very similer to something my neice had. It was called 5ths disease. . She had to grow out of it and it would effect her at random but def tell your friend to have them checked for allergys first.. im just making a suggestion

I was going to say roseola. When my daughter had it, it was only on her face, neck, back, and chest. No limbs.

Did he recently have a fever? The rash went away after 3-4 days.

If it's hot where you live or where baby's at it could be prickly heat. My daughter had that.

Heat rash? My nephew got it bad and it got worse anytime she put lotion on it.

She's been putting breast milk on it for over a week. It hasn't been hot this week either, in the 70's so beautiful weather! He hasn't had a fever and it doesn't seem to be bothering him.

My son has the same rash it's just a milk rash from her hormones. Some babies get it on their chest and back as well as their face. My son has it on his ears too, the advice is just to bathe it with water only twice a day and it will go with time.

My dd would look like this when she had days where she nursed a lot and I just figured it was from my sweat and her strong warm next to me. Is he nursing ?

Yes, he nurses exclusively. She's going to get him checked out today though, just in case!