Medications for Allergy

Milk allergy results when the immune system produces antibodies against milk allergens.

♦ Milk allergens are proteins; more than 25 distinct milk proteins have been identified in the various fractions of milk. The fractions include casein, whey serum, and certain additional ingredients (see Table INDIVIDUAL PROTEINS IN COW’S MILK).

♦ Most milk-allergic children and adults react to more than one milk protein.

♦ The potential of individual milk proteins to cause allergy has been studied by skin tests and oral challenge. Casein proteins produced the highest number of positive skin tests in children with milk allergy, whereas beta-lactoglobulin produced the highest number of positive oral challenges.

♦ More than 25 proteins in cow’s milk can induce antibody production in humans.

♦ Beta-lactoglobulin (in whey); alpha, beta, and kappa caseins; and bovine serum albumin are the most important allergens.

♦ Clinical reactions to all the major cow’s milk antigens have been documented.

Heat will change the nature of some milk proteins (they are described as heat-labile), but others remain unaffected (they are heat-stable). Serum proteins and beta-casein are the most labile and are readily denatured by heat, whereas beta-lactoglobulin and alpha-lactalbumin are the most heat-stable. This means that persons who are allergic to the heat-labile proteins will be able to drink boiled or cooked milk; those who are allergic to proteins unaffected by heat (heat-stable proteins) will not be able to drink either boiled or unboiled milk.

Table INDIVIDUAL PROTEINS IN COW’S MILK

Antibodies produced against milk proteins may be IgE, IgM, IgG, or sometimes IgA. Coupling of the milk protein antigen with its homologous (matching) antibody leads to the release of inflammatory mediators, which act directly on body tissues and cause inflammation. The tissues may be in the digestive tract, the skin, or the respiratory tract. Symptoms typical of allergy result in the affected tissues.

Milk allergy is much more common in young infants and children than in adults, so it is considered a condition of childhood rather than adulthood. More than 90% of cases of IgE-mediated allergy occur within the first year of life, the majority of these within the first six months. However, in most cases children “outgrow” IgE-mediated allergy to cow’s milk by the age of 18 months to 2 years, due to the maturing of their immune system and the lining of the digestive tract.

It is necessary to differentiate between lactose intolerance (lactase deficiency) and milk protein allergy as some symptoms, such as abdominal pain, diarrhea, and vomiting, may be common to both conditions. However, in some cases, sensitivity to milk protein may cause inflammation of the gastrointestinal tract and may lead to a lactase deficiency, so it is possible for a person to have both conditions. Symptoms in other organ systems such as the respiratory tract and the skin are not symptoms of lactose intolerance. Management of lactose intolerance is discussed in further detail later.

In order to successfully manage adverse reactions to cow’s milk constituents, whether it is an IgE-mediated allergy to cow’s milk proteins or an inability to tolerate lactose, a diet free from all sources of milk proteins and lactose is necessary. When the culprit components have been identified by appropriate challenge, the tolerated milk fractions can be reintroduced into the diet.

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This entry was posted on Wednesday, May 25th, 2011 at 2:56 am and is filed under Food Allergy. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.