Symptoms of a Milk Allergy

Milk allergies are surprisingly common, most often affecting young children. Three to 4 percent of infants suffer from allergies to milk protein, and a smaller number of adults and older children also experience it. Allergic reactions to milk tend to cause noticeable symptoms several minutes to a few hours after milk is ingested. Milk allergy symptoms can vary drastically from person to person. Symptoms may be so mild that they go relatively unnoticed, or so severe that they are acutely life-threatening.

Intolerance vs. Allergy

• Despite common misconceptions, milk intolerance and milk allergy are completely different conditions with different routes of treatment. Milk intolerance is generally more mild; it's caused by an inability to efficiently digest lactose, the primary sugar found in milk products. This reaction is limited to the digestive tract and can often be treated with digestive enzymes or lactose-free milk products.
  A true milk allergy is not a reaction to the sugar (lactose) but to the proteins found in milk. Although lactose intolerance results in gastric disturbances, milk allergies actually stimulate a histamine reaction in the body similar to the reaction caused by other food allergies. In some cases, medical tests may be necessary to determine whether symptoms are caused by milk allergy or milk intolerance.

Skin Symptoms

• Immediately after consuming milk, some people with severe milk allergies develop hives--swollen, reddish bumps that may occur in patches or throughout the body. Hives may appear to be similar to other rashes, but they develop suddenly and only in reaction to acute exposure to a severe allergen. Hives are always an indication of an overproduction of histamine, caused by allergic reaction.
  Over the course of several hours or days after exposure, milk allergies may present with rashes or skin discoloration. Milk allergies often cause or worsen chronic skin conditions such as eczema, or they may cause rashes in the mouth and on the lips. Rashes caused by allergies are often bumpy, flaky, discolored and red.

Gastrointestinal Effects

• Almost immediately after exposure to milk, some people with milk allergies experience extreme nausea accompanied by vomiting. Several hours after consuming dairy products, it's not uncommon to experience a sensation of cramping burning, or gnawing in the stomach or intestines.
  One of the most common symptoms of milk allergy is a tendency toward loose stools and diarrhea in the hours or days following consumption of milk; these may occur with or without abdominal cramping. Because diarrhea and loose stools are sometimes caused by milk intolerance, not milk allergy, it's important to monitor other symptoms to help differentiate between the two conditions.

Mucus Production

• Many people--even those without otherwise-noticeable milk allergies--experience a sharp increase in mucus production after exposure to milk. This may manifest with worsened seasonal allergies, runny nose, sneezing, post-nasal drip or coughing, and may even cause an occlusion of the nasal passages. These signs are sometimes misdiagnosed as a cold or seasonal allergies because of a similarity of symptoms.
  Increased mucus production from milk allergies may also cause bowel movements to contain noticeable traces of mucus. Because of this, stool from people with milk allergies may be discolored or contain strands of white, clear or yellowish matter.

Anaphylaxis

• Life-threatening allergic reactions to milk, in the form of anaphylaxis, are somewhat rare. When they do occur, they manifest very shortly after exposure to milk protein and require prompt treatment. Symptoms of anaphylactic shock include a rapid heartbeat, weakness, confusion, low blood pressure and hives.
  Without treatment, anaphylaxis can cause the airways to become blocked by inflammation, which can lead to death from hypoxia. Untreated anaphylaxis can also cause shock, cardiac arrest or respiratory arrest. Symptoms of anaphylaxis from any allergen should be promptly reported to a professional health care provider.