Any idea about this rash?

[cakefairy7]

I have a one month old baby, this rash has been here now for over a week anyway and it will get flare up during the day. He’s ebf but we have all also been sick with the cold for the last week and he’s got it too so I’m not sure if it’s to do with his cold, an allergy or just a baby skin problem. Doctor saw it last Friday and said nothing so the health visitors coming out tomorrow to check it

Possibly post viral rash.

I’m wondering if it’s a milk rash (bit of a reaction when posseting/saliva etc containing BM gets on skin) one of mine had it, that was 17 years ago so memory is fuzzy. Speak to HV today

Oh, poor little mite!
Rashes come and go in little ones; it could be post viral, or sweat/ dribble excoriation.
It doesn't look ominous. I would pop him in the bath with an emollient wash ( so not a 'detergent' wash). Then get a hairdryer, (on low, obviously!) And gently dry. I don't think you need creams at this stage, but, if it persists, then some Canesten with Hydrocortisone might help.

The only other thing I would consider, ( again, only if it persists,) is possible CMPA...Cow's Miilk Protein Allergy?