Milk allergy is an abnormal response by the body's immune system to milk and products containing milk. Cow's milk is the usual cause of milk allergy, but milk from sheep, goats and buffalo also can cause a reaction. Some children who are allergic to cow's milk are allergic to soy milk, too. Milk allergy is one of the most common food allergies in children.
A milk allergy usually occurs minutes to hours after consuming milk. Signs and symptoms of milk allergy range from mild to severe and can include wheezing, vomiting, hives and digestive problems. Rarely, milk allergy can cause anaphylaxis — a severe, life-threatening reaction.
Avoidance is the primary treatment for milk allergy. Fortunately, most children outgrow a milk allergy by age 3.
Milk allergy symptoms, which differ from person to person, occur a few minutes to a few hours after drinking milk or eating milk products.
Immediately after consuming milk, signs and symptoms of a milk allergy might include:
Signs and symptoms that may take more time to develop include:
Milk allergy or milk intolerance?
When to see doctor
All true food allergies are caused by an immune system malfunction. Your immune system identifies certain milk proteins as harmful, triggering the production of immunoglobulin E (IgE) antibodies to neutralize the protein (allergen). The next time you come in contact with these proteins, these IgE antibodies recognize them and signal your immune system to release histamine and other chemicals. Histamine and other body chemicals cause a range of allergic signs and symptoms. Histamine is partly responsible for most allergic responses, including runny nose, itchy eyes, dry throat, rashes, hives, nausea, diarrhea, difficulty breathing and anaphylactic shock.
There are two main proteins in cow's milk that can cause an allergic reaction:
You or your child may be allergic to only one milk protein or allergic to both casein and whey. These proteins not only are present in milk, but they're also found in processed foods. Additionally, most people who react to cow's milk will also be allergic to sheep, goat and buffalo milk. Less commonly, people allergic to cow's milk are also allergic to soy milk.
Certain factors may increase the risk of developing a milk allergy:
Children who are allergic to milk are much more likely to develop certain other health problems, including:
Preparing for your appointment
You're likely to start by seeing your family doctor, a general practitioner or your child's pediatrician. However, you may then be referred to a doctor who specializes in allergic disorders (allergist-immunologist).
Here's some information to help you get ready for your appointment and to know what to expect from your doctor.
What you can do
Preparing a list of questions can help you make the most of your time with your doctor. For a milk allergy, some basic questions to ask your doctor include:
Don't hesitate to ask any other questions that occur to you.
What to expect from your doctor
What you can do in the meantime
Tests and diagnosis
When food is the cause of an allergic reaction, it isn't always easy to pinpoint what food is to blame. To evaluate whether you or your child has a milk allergy, your doctor may:
He or she may also recommend one or both of the following tests:
If your examination and test results can't confirm a milk allergy, your doctor might administer an oral challenge, in which you are fed different foods that may or may not contain milk in increasing amounts to see if you react to the ones that contain milk.
If your doctor suspects your symptoms are caused by something other than a food allergy, you may need other tests to identify — or rule out — other medical problems.
Treatments and drugs
The only way to prevent an allergic reaction is to avoid milk and milk proteins altogether. This can be difficult because milk is a common ingredient in many foods.
Despite your best efforts, you or your child may still come into contact with milk. If this happens, medications, such as antihistamines, may reduce signs and symptoms of a mild milk allergic reaction. These drugs can be taken after exposure to milk to control an allergic reaction and help relieve discomfort. Talk with your doctor about which medications might work best for you.
If you or your child has a serious allergic reaction (anaphylaxis), you may need an emergency injection of epinephrine (adrenaline) and a trip to the emergency room. If you're at risk of having a severe reaction, you or your child may need to carry injectable epinephrine (such as an EpiPen) at all times. Have your doctor or pharmacist demonstrate how to use this device so you're prepared for an emergency.
Allergy shots, also sometimes called immunotherapy, haven't been proved effective for treating food allergies, but research is ongoing.
There's no sure way to prevent a food allergy, but you can prevent signs and symptoms by avoiding the food that causes them. If you know you or your child is allergic to milk, the only sure way to avoid an allergic reaction is to avoid milk products. Know what you or your child is eating and drinking. Be sure to read food labels carefully. Look for casein, a milk derivative, which can be found in some unexpected places, such as in some canned tuna or other meats. Ask questions about ingredients when ordering in restaurants.
Sources of milk products
Milk can be harder to identify when it's used as an ingredient in processed food products, including baked goods, processed meats and breakfast cereals. Hidden sources of milk include:
Even if a food is labeled "milk-free" or "nondairy," it may still contain allergy-causing milk proteins — so you have to read the label carefully. When in doubt, contact the manufacturer to be sure a product doesn't contain milk ingredients.
When eating out, ask how foods have been prepared. Does your steak have melted butter on it? Was your seafood dipped in milk before being cooked?
While there's no sure way to prevent an allergic reaction to milk, reading labels, being cautious when eating out, and using hypoallergenic or milk-free products can help you or your child avoid an unpleasant or dangerous reaction.
If you're at risk of a serious allergic reaction, talk with your doctor about carrying and using emergency epinephrine (adrenaline). If you have already had a severe reaction, wear a medical alert bracelet or necklace that lets others know that you have a food allergy.
Milk alternatives for infants
Milk from other animals, such as goats or sheep, isn't a good substitute for cow's milk, as these types of milk contain proteins similar to the allergy-causing proteins in cow's milk.
If you're breast-feeding and your child has a milk allergy, cow's milk proteins passed through your breast milk may cause an allergic reaction. If this is the case, you may need to exclude all products that contain milk from your diet. Talk to your doctor if you know — or suspect — your child has a milk allergy and has allergy signs and symptoms that occur after breast-feeding.
If you or your child is on a milk-free diet, your doctor or dietitian can help you plan nutritionally balanced meals. You or your child may need to take supplements to replace calcium and nutrients found in milk, such as vitamin D and riboflavin.
Coping and support
Having a serious allergy or being the parent of a child with a potentially life-threatening allergy can be stressful. Talking to others that share your situation can be helpful. Besides offering support and encouragement, they also may provide useful coping tips, such as how to deal effectively with school officials so that your child's medical needs are met. Ask your doctor if there are any support groups in your area, or contact the Asthma and Allergy Foundation of America.
Last Updated: 2011-08-11
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