Milk allergy
Milk allergy is an adverse immune reaction to one or more proteins in cow's milk. Symptoms may take hours to days to manifest, with symptoms including atopic dermatitis, inflammation of the esophagus, enteropathy involving the small intestine and proctocolitis involving the rectum and colon. However, rapid anaphylaxis is possible, a potentially life-threatening condition that requires treatment with epinephrine, among other measures.
| Milk allergy | |
|---|---|
| A glass of cow's milk | |
| Specialty | Emergency medicine Allergy & immunology |
| Symptoms | itchiness, rash, swelling of lips, tongue or the whole face, eczema, wheezing and shortness of breath, nausea, vomiting, abdominal pain, diarrhea, anaphylaxis |
| Causes | Type I hypersensitivity |
| Risk factors | Childhood in developed countries where cow's milk infant formula is introduced to supplement or after breast feeding ends |
| Diagnostic method | Medical history and standard allergy tests |
| Prevention | Introduction to allergenic foods during infancy |
| Treatment | Epinephrine Antihistamines (mild) |
| Prognosis | approximately 20% persist into adulthood |
| Frequency | 2–3% in infants, declining to 0.6% in adults |
In the United States, 90% of allergic responses to foods are caused by eight foods, and cow's milk is the most common. Recognition that a small number of foods are responsible for the majority of food allergies has led to requirements to prominently list these common allergens, including dairy, on food labels. One function of the immune system is to defend against infections by recognizing foreign proteins, but it should not overreact to food proteins. Heating milk proteins can cause them to become denatured, losing their three-dimensional configuration and allergenicity, so baked goods containing dairy products may be tolerated while fresh milk triggers an allergic reaction.
The condition may be managed by avoiding consumption of any dairy products or foods that contain dairy ingredients. For people subject to rapid reactions (IgE-mediated milk allergy), the dose capable of provoking an allergic response can be as low as a few milligrams, so such people must strictly avoid dairy. The declaration of the presence of trace amounts of milk or dairy in foods is not mandatory in any country, with the exception of Brazil.
Milk allergy affects between 2% and 3% of babies and young children. To reduce risk, recommendations are that babies should be exclusively breastfed for at least four months, preferably six months, before introducing cow's milk. If there is a family history of dairy allergy, then soy infant formula can be considered, but about 10 to 15% of babies allergic to cow's milk will also react to soy. The majority of children outgrow milk allergy, but for about 0.4% the condition persists into adulthood. Oral immunotherapy is being researched, but it is of unclear benefit.