Milk allergy is primarily seen in infants under a year old, although nearly three-quarters of these children grow out of milk allergy by the time they are 3 or 4. The number of adults in America who suffer from milk allergy is estimated to be less than 1%. However, adults’ intake of milk is considerably less than that of children, so this factor may be one reason for the smaller incidence.
Proteins commonly found in milk cause the allergic reaction. When a person becomes previously sensitized to these proteins, the immune system mistakenly identifies the proteins as foreign and threatening and releases chemicals to fight the perceived intruder. The main chemical is histamine, which dilates the blood vessels and causes fluid leakage, which in turn cause swelling (ie, angioedema), itching, and hives (ie, urticaria). Immune reactions can involve multiple areas of the body and cause mild discomfort and symptoms as well as anaphylaxis, the most severe immune response which can lead in death.
Cow’s milk contains around 30 protein components that are capable of eliciting an immune response in humans. The process of digestion itself increases the number of antigens. Ironically, curds and whey, Little Jack Horner’s favorite meal, are the two main culprits in milk allergy. Curds (otherwise known as casein) form when milk sours, and constitute about 80% of milk protein). Whey constitutes approximately 20% of milk’s protein and is itself composed of still more proteins. Some people who are allergic to milk are allergic to either curds or whey, and others to both.
An allergic reaction can be caused by touching milk, inhaling particles of milk powder, or even kissing someone who has been drinking milk. Allergic reaction times can be divided into three groups:
- Those who show symptoms immediately (within 45 minutes of contact with milk protein).
- Those who show symptoms between 45 minutes and up to 20 hours later.
- Those who show symptoms at 20 hours and over after contact with milk protein.
The symptoms of allergy sufferers in Group 1 are comprised mostly of those affecting the skin and respiratory tract. Symptoms include itchy skin or eyes, hives (urticaria), and rashes, as well as swelling of the airways, face, lips, tongue or throat, coughing, and wheezing. Members of this group have typically developed milk allergy as breast-feeding infants, and are the most likely to experience anaphylactic shock a severe and life-threatening allergic reaction.
The symptoms of allergy sufferers in Group 2 mainly involve the gut, and appear after milk has been consumed. The process of digestion can bring on nausea, flatulence, vomiting and diarrhea.
People in the third group (ie, symptoms appearing over 20 hours after contact with milk), often exhibit a combination of symptoms involving the skin and gut and sometimes the respiratory tract. Eczema, vomiting, diarrhea and even asthmatic symptoms are included in this classification.
The best way to combat the symptoms of milk allergy is to avoid contact with milk and milk byproducts. The grocery store aisles are packed with foodstuffs containing milk and some are easier to identify than others. Milk protein can be found in cereal, bread, soup, pudding, candy, ice cream, baked goods and cheese. Even some cosmetics and medicines contain milk protein or lactose. Milk sufferers must learn to read food labels carefully. Obviously anything with “milk” included in the name should be avoided (eg, dried milk, skim milk powder, pasteurized milk, etc). Some ingredients contain milk proteins (eg, casein, caseinate, and whey) and these should be avoided as well. Then there are those ingredients, that don’t give any clue as to whether they contain milk. For example some emulsions are made with milk, therefore a product containing “emulsifier” should be avoided until further information about the food can be obtained.