What Are the Symptoms of a Milk Allergy in Adults?

Milk contains water, proteins, minerals, fats and carbohydrates (lactose is the milk sugar). Those who are allergic to milk have a reaction to the proteins, which in cow’s milk are whey found in the liquid portion and casein found in the solid or curd portion. Although more common in infants and children, adults can develop an allergy to milk in their 30s and 40s, according to Allergy Escape 12. The symptoms induced by a milk allergy can affect the skin, the digestive system and the respiratory system 12.


The symptoms of a milk allergy can occur within minutes from ingesting a product containing milk 12. Often a rash forms on the skin around the mouth first and then may occur all over the body. The rash may appear red and bumpy as hives or may just be patches of red dry skin similar to eczema.

Some of those allergic to milk may react with what is called allergic shiners. This is the appearance of black circles around the eyes that look like a typical black eye.

Intestinal Discomfort

Many people often confuse a milk allergy with lactose intolerance 12. Although both conditions can cause intestinal discomfort, lactose intolerance is strictly a digestive issue, whereas a milk allergy is an immune response 12. For those allergic to milk, their body sees milk proteins as foreign invaders, and the white blood cells attack them and produce antibodies against them. The body releases chemicals called histamines, which are what cause the symptoms of the allergy.

A milk allergy will cause intestinal cramping and abdominal bloating 12. Nausea and vomiting also may occur.

Trouble Breathing

For those allergic to milk, when milk proteins are ingested, the body’s immune system responds. This triggers inflammation, which can occur in the sinuses. The inflammation causes an overproduction of mucus, resulting in the common symptoms of a stuffy and runny nose. The increase in mucus production can also cause watery eyes.

Inflammation of the trachea and bronchi (the tubes that lead to the lungs) can inhibit the flow of air and create trouble breathing. Symptoms can include wheezing, coughing and asthma.

Anaphylactic Shock

Anaphylactic shock, also called anaphylaxis, is a severe and potentially life-threatening allergic reaction. Although a rare reaction to a milk allergy, it can occur 12. When the body’s immune system attacks the milk proteins, the large amount of chemicals released in the body can trigger shock. The symptoms include:

  • a sudden drop in blood pressure
  • airway constriction
  • rapid weak pulse
  • rash
  • nausea
  • vomiting