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|Classification and external resources|
A milk allergy is a food allergy, an adverse immune reaction to one or more of the constituents of milk from any animal (most commonly alpha S1-casein, a protein in cow's milk). This milk-induced allergic reaction can involve anaphylaxis, a potentially life-threatening condition.
Milk allergy is distinct from lactose intolerance.
Alpha S1-caseins differ between species. This explains why someone with an allergic reaction to sheep's milk cannot drink goat's milk but can drink breast milk without an allergic reaction.
The principal symptoms are gastrointestinal, dermatological and respiratory. These can translate to: skin rash, hives, vomiting, and gastric distress such as diarrhea, constipation, rhinitis, stomach pain or flatulence. The clinical spectrum extends to diverse disorders: anaphylactic reactions, atopic dermatitis, wheeze, infantile colic, gastroesophageal reflux (GER), oesophagitis, allergic colitis, headache/migraine, tachycardia, oral irritation, and constipation.
The symptoms may occur within a few minutes after exposure in immediate reactions, or after hours (and in some cases after several days) in delayed reactions.
Milk allergy is a food allergy, an adverse immune reaction to a food protein that is normally harmless to the non-allergic individual. Lactose intolerance is a non-allergic food sensitivity, and comes from a lack of production of the enzyme lactase, required to digest the predominant sugar in milk. Adverse effects of lactose intolerance generally occur after much higher levels of milk consumption than do adverse effects of milk allergy.
Lactose intolerance is considered the normal state for most adults on a worldwide scale and is not typically considered to be a disease condition.
Milk protein intolerance (MPI) is delayed reaction to a food protein that is normally harmless to the non-allergic, non-intolerant individual. Milk protein intolerance produces a non-IgE antibody and is not detected by allergy blood tests. Milk protein intolerance produces a range of symptoms very similar to milk allergy symptoms, but can also include blood and/or mucus in the stool. Treatment for milk protein intolerance is the same as for milk allergy. Some people may also have an intolerance to soy protein(s), this combination called a milk soy protein intolerance.
The main treatment for milk allergy is total avoidance of milk proteins. Products in addition to milk itself to be avoided by those with milk allergy include yogurt, butter, cheese, and cream. Goats' milk products may also need to be avoided. In extreme cases, rare, or un-cooked beef may also cause a mild reaction.
Ingredients that also denote that food product contains dairy milk include whey, casein, caseinate, butter flavor, lactic acid (lactic acid derived from dairy products), natural or artificial flavors such as milk or butter flavor, and sodium caseinate.
It is commonplace for milk or milk derivatives to be included in processed foods such as bread, crackers, cookies, cakes, prepared meats, "soy cheese", soups, gravies, crisps, margarine, and products labeled "non-dairy", such as whipped topping and creamer (non-dairy simply means less than 0.5% milk by weight).
It is also commonplace for milk derivatives, like casamino acid, to be in vaccines.
In some cases, heating the dairy product to force an exothermic chemical reaction can denature the proteins, (e.g. baking bread, or other baked goods). Only the ingredients that are chemically reacting will denature. Consequently, some allergic people are able to tolerate cooked foods that contain some milk.
It is important to note that many processed foods that do not contain milk may be processed on equipment contaminated with dairy foods, which may cause an allergic reaction in some sensitive individuals.
Since milk protein may be transferred from a breastfeeding mother to an allergic infant, lactating mothers of allergic infants can simply be put on a dairy elimination diet. For formula fed infants, milk substitute formulas are used to provide a complete source of nutrition. Milk substitutes include soy based formulas, hypoallergenic formulas based on partially or extensively hydrolyzed protein, and free amino acid-based formulas.
Non-milk derived amino acid-based formulas, known as amino acid formulas or elemental formulas, are considered the gold standard in the treatment of cows milk allergy when the mother is unable to breastfeed.
Hydrolyzed formulas come in partially hydrolyzed and extensively hydrolyzed varieties. Partially hydrolyzed formulas (PHFs) are characterized by a larger proportion of long chain peptides and are considered more palatable. However, they are intended for milder cases and are not considered suitable for treatment of moderate to severe milk allergy or intolerance. Extensively hydrolyzed formulas (EHFs) are composed of proteins that have been largely broken down into free amino acids and short peptides. Casein and whey are the most commonly used sources of protein in hydrolyzed formulas because of their high nutritional quality and their amino acid composition.
Soy based formula poses a risk of allergic sensitivity, as some infants who are allergic to milk may also be allergic to soy. Formula of any kind is not recommended for infants under 6 months.
There are many commercially available replacements for milk for children and adults. Rice milk, soy milk, oat milk, coconut milk, almond milk, or milk based on carob seeds are sometimes used as milk substitutes.
On an avoidance diet, it may be possible to reduce the longer-term risk of calcium deficiency and osteoporosis by incorporating other sources of calcium, although the effect of calcium and vitamin D supplementation on osteoporosis is not always clear. There are fruit juices supplemented with calcium, sesame seeds, hemp seeds and some kinds of tofu.
Treatment for accidental ingestion of milk products by allergic individuals varies depending on the sensitivity of the allergic person. Frequently medications such as an Epinephrine pen or an antihistamine such as diphenhydramine (Benadryl) are prescribed by an allergist in case of accidental ingestion. Milk allergy can cause anaphylaxis, a severe, life-threatening allergic reaction.
Desensitization, which is a slow process of eating tiny amounts of milk, until the body is able to tolerate more significant exposure, results in reduced symptoms or even remission of the allergy in some people. Sometimes this is done by putting a tiny amount of milk under the tongue, which is called sublingual immunotherapy. The other main approach for milk allergy involves eating a small amount of milk, perhaps baked into food. This is called oral immunotherapy. Sublingual immunotherapy may be somewhat safer but less effective. However, this may not be permanent and is still being researched.
Milk allergy is the most common food allergy in early childhood. It affects somewhere between 2% and 3% of infants in developed countries, but approximately 85–90% of affected children lose clinical reactivity to milk once they surpass 3 years of age. The prevalence of milk allergy in adults is between 0.1% and 0.5%.
Between 13% and 20% of children allergic to milk are also allergic to beef.
It is advisable to try and identify the offending agents early especially in patients with high risk and avoid them for a better long term prognosis.