Re-appearing rash on 4 month old

[Becky6X]

Does anyone have any idea what this looks like? This rash comes and goes quite often and has done for around a month. It's mostly on his neck, behind ears and top of back, sometimes chest.

I always say I'll mention it to the health visitor but it goes as quick as it comes and then I forget to. It will come and 10 minutes later disappear completely.

Thanks!

Hi Op could it be a sweat/heat rash? I was going to say possible eczema but if it goes quickly then that's unlikely to be I would ask your HV now that you have the photo show them set a reminder in your phone when your next due to see HV to remind you it's so hard I do the same forget stuff to ask all the time