Hi
It seems that your child has milk
protein allergy.
Lactose intolerence,
Milk allergy and Milk protein allergy are three closely related but different situations that people may get confused.
Lactose Intolerance - due to lack of enzyme Lactase, that break down the milk protein to simpler forms to be absorbable for body. May be primary due to genetical inability to produce lactse, or secondary due to Antibiotics treatment. Symptoms - dirrhoea,
blood in stool, itchy rashes etc.
Milk allergy - Allergy to variety of
proteins present in milk (commonly -Alpha S1-
Casein) that leads to hypersensitive reactions . Smptoms -
urticaria, rashes - an emergency.
Milk protein allergy - allergy to variety of milk protein like milk allergy (but the antibody is of different nature). Symptoms are like milk allergy but varies in severity.
As cooking (heating ) causes structural changes in protein, cooked milk product in food may not cause severe symptoms / allergy as the allergen (protein) may not present there. Child may be more tolerant to conventionally prepared yogurt because of lactase produced by bacteria during preparation or boiling the milk before preparation denatures the milk proteins . However, yogurt with more milk solids (sometimes present in commercial yogurts) may cause intolerance.
So, it is better not to be aggressive with introducing non-cooked dairy products to your child. Most of the cases, milk allergy subsides once the child reach above three year age.
Try to wean off with rice / wheat / dal / pulses etc, by making well cooked semisolid food. Then gradually to regular diet. Avoid raw dairy products now. Cooked milk products, as in your case, is OK.