As far as we can tell, no one knows! As with most allergies you can inherit it, although that doesn’t mean that parents who are allergy will pass it on, just a bit more likely. It’ not that you pass on the specific allergy, just that you pass on a susceptibility to having allergic reactions. How strong and fast your immune system develops and whether it gets challenged at a young age would probably also be contributing factors.
It has been noted that there are basically three different groups sufferers. The first group reacts immediately, within 45 minutes of drinking cows milk. These people may have either urticaria, angio-oedema and possibly a true anaphylactic reaction. The second group may take from 45 minutes to 20 hours to exhibit pallor, vomiting and diarrhoea. The third group may take longer than 20 hours and have mixed reactions involving the skin, respiratory tract and gut.
Further information can be found in Hill D J et al. A study of 100 infants and young children with cow’s milk allergy. Clinical Reviews in Allergy 1984; 2:125
“Milk protein allergy” is an allergic reaction to proteins commonly found in cows milk. It is caused by your immune system reacting because it believes the protein in the milk is a threat to your body. Your immune system will do it’s best to get rid of the invader, just as it would a foreign virus or poison. During the allergic reaction your body releases histamine, a chemical which causes blood vessels to dilate and leak, mucous membranes to start producing and other effects.
The leaking blood vessels causes redness and itching over certain parts of the body or even all of it. The increased mucous may make you congested. Other reactions include nausea, vomiting, diarrhoea and behavioural changes. It can also lead to anaphylaxis in which the patient’s air passages swell and close and blood pressure falls abruptly, leading, if untreated to death.
From our experience, the attack will last for about 1 to 2 hours. See “Rhiannon’s Story” for typical graphic details. On the other hand, depending on where the allergic reaction occurs in the digestive tract, it might take up to 8 hours, or more.
The doctors initially said our daughter would probably grow out of it by the time she is two or three. She is now nearly seven and shows no sign of out-growing it at all. Maybe when she’s 10 or so…. they now say. Each child is different and how long it takes their immune system to come to grips with it will vary. Just take each year as it comes, don’t build up expectations and see what happens. In our case , our daughter fights off flu’s easily that totally lay mum and dad low, her “over-reactive” immune system seems to have built up a pretty good repertoire of anti-bodies. We see this as a bit a reward for the rest of the hassle!