Don’t confuse lactose intolerance with dairy allergy as they are completely different things which a lot of people aren’t aware of.
And there is no such thing as an ‘intolerance’ these days, it is solely classed as an allergy. Just because the baby doesn’t have an anaphylactic reaction does not mean they aren’t allergic to it. Look up IgE and non-IgE reactions as that is how the allergy is assessed.
My son was EBF and was diagnosed with CMPA when he was
9 weeks old due to really bad skin and pain after feeds. I cut out dairy and within a month he was a completely different baby.
On a few occasions I trialled having dairy (which is standard procedure in order to confirm the allergy) and both times my son reacted awfully within hours after a breast feed.
He is now 16 months, still breast fed, and still can’t tolerate my having full milk in my diet. I can have other forms of dairy now, melted cheese, chocolate etc, but yogurts and cows milk are an absolute no-go.
When he has a reaction to dairy his nappies are vile! Very loose and strong smelling, very acidic.
Your baby’s symptoms definitely sound symptomatic of CMPA so even if the GP brushes you off (a lot of them think breast fed babies can’t be allergic for some reason) just remove dairy from your diet anyway and see what happens. As an aside, soya is a very similar protein to that found in cow’s milk so it is usually advised to remove that too.
Removing dairy and soya can be very hard at first but when you see an improvement (hopefully) in your baby then it makes it all worth it.
If you do remove dairy the general rule is that after 6 weeks have a dairy binge (I had a massive chocolate milkshake and lots of chocolate) and see what happens - if your baby’s symptoms return then it confirms the allergy.
If that is the case then go back to the GP and ask to be referred to an Allergy Team. You will also need a referral to a Dietician but your HV can do that.
Good luck OP 