The Effect of Baked Milk on Cow's Milk Allergy

Food allergy, as an immune based hypersensitivity reaction, is estimated to be about 6% in young children and 3-4% in adults [1, 2]. Its pathophysiology is defined trough both IgE and non-IgE mediated mechanisms, which lead to skin, gastrointestinal, respiratory and systemic manifestations [1]. This type of allergy is mostly seen trough the first year of life. One study showed that about 2.5% of the neonates show allergy to cow's milk [3].

Most of food allergens are cow's milk, chicken egg, corn, soya, peanut, dried fruits, and fishes. Among them, cow's milk is considered to be the most common one, specifically, among the children [1, 2].

This allergen consists of about 20 proteins which all can induce immune system to produce antibodies. The two major protein components of milk are casein and whey. About 76 to 86% of it is casein, which is responsible for the IgE mediated immune response. On the other hand, whey, which is composed of alpha-lactalbumin, beta-lactoglobulin, and albumin, is mostly induced systemic allergic reactions [4].

Boiling the milk at 95 c for 20 minutes can damage some whey's protein components; however, it cannot damage the major milk's allergens. Pasteurization is also shown to have no effect on these allergens [5].

It was shown that IgE mediated mechanisms are involved in lifelong cow's milk allergy. In spite of that, about 50% of children up to 1 year old and 85% up to 3 years old develop by tolerance to milk's allergen [6].

Oral food challenge (OFC) test confirming by skin prick test and serum IgE levels is one of the most sensitive tools for diagnosis of food allergy. It was shown to have sensitivity about 95 % and specificity about 50%[7].

Comparing baked milk and non-heated milk allergy was shown that ones with allergy to baked milk have more chance of developing anaphylactic reactions. Some studies on patients who can tolerate baked milk suggest that adding these products to the daily diet of sensitive children can improve tolerance to cow's milk [8, 9]. On the other hand, another study in Australia showed that phenotype is the strongest predictor of tolerance development and altered allergen such as baked milk does not have significant effect in this process [10].

Thus, according to the controversies on effect of baked milk in immunotherapy of cow's milk allergy as well as the necessity of developing a safe method of milk's allergy due to high risk of anaphylactic reactions to milk's products in patients, it seems to be essential to perform a study assessing the possibility of tolerance induction by baked milk in cow's milk allergic children.

Inclusion criteria

• The patients' ages between 6 months to 18 years old.
• Having positive histories of cow's milk allergy presenting by dermal, gastrointestinal, respiratory or systemic manifestations.
• Confirmed cow's milk allergy by standard diagnostic tools such as skin prick test more than 8 millimeters or serum IgE levels higher than 5 KIU/L up to 2 years old and 15 KIU/L in other ages.
• Cases who have tolerance to baked milk products confirmed by oral food challenge test.

Exclusion criteria

• Ones with low serum IgE levels and negative skin prick test for milk products.
• Ones with positive histories of unstable asthma.
• Ones with eosinophilic gastrointestinal disorders.
• Ones with history of allergy to baked milk products in last 6 months.
• Ones with positive history of severe anaphylactic reaction to milk and its products in last 6 months.
• Ones with positive allergy history to chicken egg or wheat.
• Patients with celiac disease.