Milk allergy

Milk allergy is one of the most common food allergies in children. Although cow's milk is the usual cause of milk allergy, milk from sheep, goats and buffalo also can cause a reaction. And, some children who are allergic to cow's milk are allergic to soy milk too.

A milk allergy usually occurs a few minutes to a few hours after you consume 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.

Symptoms

Milk allergy symptoms differ from person to person and occur within a few minutes to a few hours after ingesting milk.

Immediately after consuming milk, signs and symptoms of a milk allergy might include:

• Hives
• Wheezing
• Vomiting

Signs and symptoms that may take more time to develop include:

• Loose stools, which may contain blood
• Diarrhea
• Abdominal cramps
• Coughing or wheezing
• Runny nose
• Watery eyes
• Itchy skin rash, often around the mouth
• Colic, in babies

Milk allergy or milk intolerance? 
It's important to differentiate a true milk allergy from milk protein intolerance or lactose intolerance. Unlike a milk allergy, intolerance doesn't involve the immune system. Milk intolerance causes different symptoms and requires different treatment than does a true milk allergy. Common signs and symptoms of milk protein or lactose intolerance include digestive problems, such as bloating, gas or diarrhea, after consuming milk or products containing milk.

Anaphylaxis 
Rarely, milk allergy can cause anaphylaxis, a life-threatening reaction that can narrow the airways and block breathing. If you or your child has a reaction to milk, tell your doctor about it no matter how mild the reaction was. Tests can help confirm a milk allergy, so you can take steps to avoid future and potentially worse reactions. Anaphylaxis is a medical emergency and requires treatment with an epinephrine (adrenaline) shot and a trip to the emergency room. Signs and symptoms start soon after consuming milk and can include:

• Constriction of airways, including a swollen throat that makes it difficult to breathe
• Facial flushing
• Itching
• Shock, with a severe drop in blood pressure

When to see doctor
See a doctor or allergist if you experience milk allergy symptoms shortly after consuming milk. If possible, see your doctor when the allergic reaction is occurring. This will help the doctor make a diagnosis. Seek emergency treatment if you develop any signs or symptoms of anaphylaxis.

Causes

All 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, labored breathing and anaphylactic shock.

There are two types of protein in cow's milk that can cause an allergic reaction:

• Casein, which is found in the solid part (curd) of milk that curdles
• Whey, which is found in the liquid part of milk that remains after milk curdles

You or your child may be allergic to only one milk protein or allergic to both casein and whey. These proteins are not only present in milk — but also are 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.

Risk factors

Certain factors may put you at greater risk of developing a milk allergy:

• Other allergies. Many children allergic to milk also have other allergies. Often, however, milk allergy is the first to develop.
• Atopic dermatitis. Children with this type of skin reaction are much more likely to develop a food allergy.
• Family history. You're at increased risk of a food allergy if one or both of your parents have a food allergy or another type of allergy — such as hay fever, asthma, hives or eczema.
• Age. Milk allergy is more common in children. As you grow older, your digestive system matures and your body is less likely to react to milk.

Complications

Children who are allergic to milk are much more likely to develop certain other health problems, including:

• Allergies to other foods — such as eggs, soy, peanuts or even beef
• Hay fever — a reaction to pet dander, dust mites, grass pollen and other substances

Tests and diagnosis

When food is the cause of an allergic reaction, it isn't always easy to pinpoint the exact food that's to blame. To evaluate whether you or your child has a milk allergy, your doctor may:

• Ask detailed questions about signs and symptoms
• Perform a physical exam
• Have you keep a detailed diary of the foods you or your child eats
• Have you eliminate milk from your diet or your child's diet (elimination diet) — and then have you add back the food to see if it causes a reaction

He or she may also recommend one or both of the following tests:

• Skin test. In this test, your skin is pricked and exposed to small amounts of the proteins found in milk. If you're allergic, you develop a raised bump (hive) at the test location on your skin. Allergy specialists usually are best equipped to perform and interpret allergy skin tests. This type of test isn't always accurate for detecting a milk allergy.
• Blood test. A blood test can measure your immune system's response to milk by measuring the amount of certain antibodies in your bloodstream, known as immunoglobulin E (IgE) antibodies. A blood sample is sent to a medical laboratory, where it can be tested for evidence of sensitivity to milk. However, this test isn't always accurate in correctly identifying a milk allergy either.

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, as 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 that you're prepared for an emergency.

Allergy shots, also sometimes called immunotherapy, haven't been proven effective for treating food allergies, but research is ongoing.

Prevention

There's no sure way to prevent a food allergy from occurring in the first place — 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.

Some research suggests that breast-feeding during the first four months of a baby's life instead of giving a standard cow's milk formula can help prevent milk allergy.

In children who are allergic to milk, breast-feeding and use of hypoallergenic formula can prevent allergic reactions.

• Breast-feeding is the best source of nutrition for your child. Experts recommend breast-feeding for at least the first four to six months of life if possible, especially if your infant is at high risk of developing a milk allergy. Breast-feeding may reduce your baby's chance of developing a milk allergy. Your doctor may also recommend eliminating cow's milk from your diet while nursing your baby if you have a strong family history of food allergy.
• Hypoallergenic formulas are produced by using enzymes to break down (hydrolyze) milk proteins, such as casein or whey. Further processing can include heat and filtering. Depending on the level of processing, products are classified as either partially or extensively hydrolyzed. Or, they may also be called elemental formulas. Some hypoallergenic formulas aren't milk based, but instead contain amino acids. Along with extensively hydrolyzed products, amino-acid-based formulas are the least likely to cause an allergic reaction.
• Soy-based formulas are based on soy protein instead of milk. Soy formulas are fortified to be nutritionally complete — but, unfortunately, some children with a milk allergy also develop an allergy to soy.

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. What's more, children who are allergic to cow's milk may also be allergic to soy 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.

Hidden sources of milk products 
Allergy-causing milk proteins are found in dairy products, such as yogurt, cheese, butter, half-and-half and sour cream. But milk can be harder to identify when it's used as an ingredient in processed food products ranging from sausage to breakfast cereals. Hidden sources of milk include:

• Whey
• Casein
• Ingredients that contain the prefix "lact" — such as lactose and lactate
• Candies, such as chocolate, nougat and caramel
• Fat-replacement products, such as Simplesse
• Protein powders
• Artificial butter flavor
• Artificial cheese flavor
• Hydrosolate

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.