The prevalence of allergies to cow's milk

In the data presented by different authors, the various figures illustrate the prevalence of allergies to cow's milk. This is due to the fact that the research results are affected by a number of factors.
1. Different groups surveyed. In patients suffering from any illness or disease, especially in subjects in Allergy clinics, one should expect a greater prevalence of allergies to milk than the rest of the population.
2. The method of feeding the child. In children receiving cow's milk since birth, we can expect greater frequency of allergic reactions to it than those who began to receive it later [11, 12]. On average prevalence of allergies to milk, apparently, much lower in countries where the predominant breastfeeding.
3. Age. Allergy to cow's milk is mainly a disease of children under the age of 2 years, and its prevalence is falling sharply in children older than 2 or 3 years [13, 14].
4. The attitude of the researcher to the problem. It is understandable that are allergic to milk rather be diagnosed by those professionals who are convinced of its existence, than those who are skeptical about it.
5. Diagnostic criteria. The diagnosis of Allergy to cow's milk bet too often, when it is based only on the disappearance of symptoms in the single exception of milk from the diet. On the other hand, cannot be used as a simple criterion of any one laboratory analysis, because you can miss many cases of true Allergy to milk. This also applies to those cases when the disappearance of the symptoms of allergies after three exceptions milk from the diet and their recurrence after taking milk. According to A. Goldman [15], only 12.7% of cases with suspected allergic meet these criteria.
6. Study type. Retrospective studies are less reliable, because the diagnosis was set by different doctors without any pre-established criteria.
7. The duration of the study. The longer the monitoring of patients, more often and more carefully survey, the more will be diagnosed patients, symptoms which can be associated with allergies to milk.
According to different authors, the prevalence of allergies to cow's milk varies from 0,3 up to 7.5% (table. 1). Apparently, the average number of this Type of Allergy in children in Western countries is 1-3%. Thus, in the USA, where born annually more than 3 million children, it can be expected that with the current feeding practices from 30 000 to 90 000 children annually will suffer from allergies to cow's milk.