What's the best first substitute for cow's milk if you suspect an intolerance?

[BR44]

My 13mo son has had a mild but persistent rash around his nose and mouth for about 4 months. I haven't thought much of it until now. The GP put it down to teething/colds etc but it is not getting any better and is starting to puzzle me. I wondered if it might be a food intolerance and after doing a bit of reading online last night I thought I'd cut out cow's milk for a while and see if there's any difference. I haven't noticed a pattern with any other specific food consumption and he currently has dairy every day. I understand it's the most common intolerance in small children?

He does eat a lot of cheese and yoghurt but I can easily stop these completely for a while but I still need milk of some sort for breakfast and cooking. (He's still BF too so I'm not too worried about milk as a drink). My first thought was goats milk but apparently the protein is very similar to that in cow's milk, so am I better off with another alternative and, if so, which? I really don't want to give him anything unsuitable for his age.

I use Koro coconut milk and DS loves it. Oatly is supposed to be very nice too and possibly better in cooking.

We use oat milk for dairy allergic DD2 (and it's what I used when I was bf her as I had to exclude dairy and egg too). I was told to avoid soy (potential for allergy also, and she doesn't seem to be able to take large amounts of it) and rice milk (not suitable for under 5s). Almond milk is another option if there is no issue around nuts, but I thought it tasted horrible and chalky.

We've switched to A2 milk which is still cow's milk but is minus a particular protein. It seems to have single handedly got rid of DD's constipation which she'd had for over a year! Maybe worth a try?

Why can't under 5s have rice milk? Surely it's just rice and water

due to arsenic levels I believe

nhs says:

Young children (under five years) should not be given rice drinks as they contain inorganic arsenic. Don't worry if your child has already had rice drinks. There is no immediate risk to children who have been consuming rice drinks, and it is unlikely that there would have been any long-term harmful effects. But to avoid them taking in any more inorganic arsenic, you should stop giving them rice drinks and switch to a different kind of milk.

We use oatly which tastes fine. Coconut milk is ok too. Almond milk is horrible stuff!
Agree with pp -we were told no soy or rice milk.

Ds would drink anything, loves Almond and coconut milk especially

I didn't know there was arsenic in rice milk, I use it.

DS has an intolerance to dairy but it shows as diarrhoea and stomach cramps, so we use the lactofree range. I think this is different to an allergy though. I am allergic to milk and react even to the lactofree, goats, sheeps etc, hence using rice milk.

if he is ok with lactofree then that suggests a problem with the lactose (milk sugar) whereas if you cannot tolerate any cows milk products then that suggests a problem with the cows milk protein (rather than the sugars in the milk)

Koko coconut milk is lovely. I use it all the time now because I prefer it to cows milk.

summerflower I think the levels of arsenic are well within acceptable ranges for an adult - just that they urge caution for children having it as their main milk drink.

Koko milk. If you heat it up, and add porridge/oats to it, you can't tell the difference.

I would eliminate dairy, soya and egg for 2 weeks and see if it makes a difference. My DD is allergic to wheat too (something we were not expecting)