Do I Have a Milk Allergy? Here’s How to Tell

If you or your child experiences itchy, red bumps (welts) on the skin, stomach problems, or difficulty breathing after consuming milk products, you could have a milk allergy.

Cow's milk or dairy allergy is relatively common in children and is often outgrown by adulthood. Unlike lactose intolerance, a milk allergy occurs when the immune system mistakenly identifies milk proteins as harmful, leading to mild to life-threatening symptoms.

This article discusses the symptoms of a milk allergy, foods to avoid, and what may bring it on suddenly.

What It Means to Have a Milk Allergy

A cow's milk allergy is one of the most common food allergies, affecting up to 3% of children under 3 years old. While 80% of children outgrow their milk allergy by age 16, it may persist into adulthood.

Milk allergies occur when the immune system recognizes the proteins in milk as harmful and overreacts, producing immunoglobulin E (IgE) antibodies. These antibodies travel to cells that trigger the release of chemicals that cause an allergic reaction.

Cow's milk contains at least 20 potentially allergic proteins, with whey and casein being the main ones. Many people with cow's milk allergy react to several milk proteins at once.

Although the cause is poorly understood, a person may also have a non-IgE milk allergy not caused by allergic antibodies. However, unlike lactose intolerance, reactions are still caused by the immune system.

Non-IgE-mediated forms of milk allergy include:

• Food protein-induced enterocolitis syndrome (FPIES), causing vomiting and diarrhea
• Food protein-induced proctitis (FPIAP), causing inflammation in the last part of the colon
• Food protein-induced enteropathy (FPE), causing diarrhea and malabsorption (inability to take in nutrients from food)
• Eosinophilic esophagitis (EoE), causing inflammation in the esophagus (food tube) due to a single white blood cell (eosinophil)
• Heiner syndrome, causing coughing, wheezing, difficulty breathing, and nasal congestion and runny nose

Sudden or Recurring Milk Allergy Symptoms

Milk allergy symptoms generally begin to appear within the first year of life. A sudden milk allergy in adults can happen, but it is rare. Researchers aren't sure exactly why it may occur.

Symptoms of classic IgE-mediated milk allergy often appear within minutes of eating. They can be unpredictable, ranging from mild to severe. Common symptoms include:

• Hives
• Upset stomach
• Vomiting
• Bloody stools (primarily in infants)
• Anaphylaxis

In non-IgE-mediated milk allergy, symptoms are delayed and may take up to 48 hours to develop. They aren't life-threatening and primarily affect the gastrointestinal tract, causing diarrhea, bloody stools, and weight loss. However, they may also affect the skin and respiratory tract.

Can You Suddenly Become Lactose Intolerant?

Lactose intolerance occurs in people who have trouble digesting lactose, a sugar in milk and dairy products. It causes symptoms such as gas, bloating, nausea, and abdominal pain after eating lactose-containing foods.

Lactose intolerance can occur suddenly, even if you've never had a problem eating or drinking dairy products.

Its sudden onset is often triggered by illness, infection, or surgery that affects your small intestine. This includes conditions like celiac disease, Crohn's disease, and illnesses that cause diarrhea.

Unlike those with a milk allergy, people with lactose intolerance can often tolerate small amounts of milk and other dairy products.

Dairy-Free Choices With a Milk Allergy

Many non-dairy alternatives are available if you have a milk allergy and need to avoid it. Some popular options include:

• Almond milk
• Coconut milk
• Hemp milk
• Cashew milk
• Pea milk
• Oat milk

Most grocery stores sell nondairy butter, yogurt, ice cream, cheese, and chocolate.

Dairy-free milk alternatives typically have fewer calories, grams of protein, and other nutrients than cow's milk. However, many brands fortify their milk alternatives with vitamin D and calcium, helping consumers meet their nutritional needs while sticking to their diets.

Always read the food label to ensure you choose the best product to meet your nutrient needs.

What to Avoid With a Milk Allergy

If you have a cow's milk allergy, avoiding milk and other foods containing milk proteins is important. Common sources of milk proteins include:

• Butter and butter fat
• Ghee (semifluid clarified butter)
• Milk, including powdered milk, buttermilk, condensed milk, and evaporated milk
• Cheese, including cottage cheese and cream cheese
• Ice cream
• Pudding
• Yogurt
• Sour cream
• Whey and casein protein powder

Milk products may also be hidden in commonly eaten foods, including:

• Chocolate and caramel candies
• Bread, pasta, and tortillas
• Sherbet
• Tuna fish (some brands contain casein)
• Margarine and artificial butter flavor
• Breakfast cereals, pancakes, and waffles
• Baked goods and desserts
• Deli meat, hot dogs, and sausage (may use casein as a binder)
• Steaks and other meats from restaurants that may be prepared with butter

If you have a cow's milk allergy, you may also react to goat milk and milk from other domestic animals. This is because the proteins in goat's milk are similar to those found in cow's milk.

Summary

Cow's milk allergy occurs when the immune system overreacts to milk proteins. It can trigger hives, an upset stomach, bloody stools, or even a life-threatening reaction called anaphylaxis.

While it's uncommon to develop an allergy to milk proteins in adulthood, it's possible to develop lactose intolerance at any age. Lactose intolerance can lead to similar digestive symptoms but does not involve the immune system like a milk allergy.

If you are experiencing symptoms after consuming milk or dairy products, it's important to see your healthcare provider. They can determine whether an allergy or intolerance is present and suggest appropriate treatment recommendations to help you manage your condition.