Milk Allergies and Intolerance in Babies

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We often hear about people who can’t have dairy products — milk, cheese, yogurt and ice cream. Lactose intolerance is common in older children, adolescents and adults. In fact, up to 70 percent of the world’s population is affected; however, the condition varies with ethnicity. Lactose intolerance rarely occurs in infants.

Lactose is a sugar found exclusively in mammalian milk, such as cow’s milk and human milk. Lactose intolerance occurs when the intestines do not make enough of the enzyme lactase to digest the lactose. The undigested sugar travels to the large intestine and becomes food for the normal bacteria living there. As a result, as bacteria break down the lactose, gas and acid are produced, which cause symptoms such as pain, nausea, diarrhea and bloating. This can start shortly after a meal or several hours later. The severity usually is related to the amount of lactose ingested.

Premature babies born between 28 and 32 weeks gestation can have a deficiency of lactase, the enzyme that helps the body absorb lactose. But preemies usually do not experience significant symptoms. As these infants mature, lactase activity increases to allow for easier digestion of milk products.

How is lactose intolerance diagnosed?

In older children and adults, doctors recommend a lactose-free diet for two weeks. If symptoms disappear and then return within four hours of ingesting milk, it’s likely the problem is lactose intolerance. Sometimes stool testing or a hydrogen breath test can aide diagnosis. In some cases, consulting with a gastroenterologist may be necessary.

If your baby is lactose intolerant, the pediatrician will recommend a lactose-free formula, or a lactose-free diet for the breastfeeding mother. Because the nutrients in milk products are important for growth, check with your doctor before switching formulas or changing your diet (if breastfeeding). Goat’s milk, rice milk and almond milk are NOT recommended for infants.

What is cow’s milk protein allergy?

This is far more common in infants than lactose intolerance. A milk protein allergy occurs when the immune system mistakenly sees the milk protein as something the body should fight off. This starts an allergic reaction, which can cause a baby to become fussy and irritable.

Symptoms of a milk protein allergy start most commonly by 1 month of age and usually get better by 1-2 years of age, although some children never outgrow it. Symptoms include vomiting, reflux, feeding problems, diarrhea (occasionally with streaks of blood or mucus), skin rash or fussiness. Cow’s milk protein is similar to soy protein, and up to 50 percent of babies with cow’s milk protein allergy also will have symptoms with soy formula.

So what should I feed my baby?

If cow’s milk protein allergy is suspected, your baby’s doctor may suggest avoidance of cow’s milk products for the breastfeeding mother, because the milk protein crosses into the breast milk. If this does not decrease the infant’s symptoms, a trial of hypoallergenic formula may be warranted. But be assured that Mom can pump her breast milk to continue with breast milk production during this trial period.

Many infants with cow’s milk protein allergy require a partially hydrolyzed or extensively hydrolyzed formula to reduce symptoms. These formulas are expensive and first should be discussed with your pediatrician. The two most commonly tried formula types are:

• Extensively hydrolyzed formulas (Nutramigen®, Pregestimil®, Alimentum®). These formulas have cow’s milk protein that is broken down into smaller particles that are less likely to cause symptoms. Most infants who have a milk protein allergy can tolerate these formulas.

• Amino acid-based infant formulas (Neocate®, Elecare®,Nutramigen AA®). These formulas contain protein broken down into its simplest form, called amino acids. This may be recommended if your baby continues to have problems after switching to a hydrolyzed formula.

Many infants will outgrow cow’s milk protein allergy by age 1-2. Breast or formula feeding is recommended until the first birthday, at which time your baby’s doctor may recommend gradually introducing cow’s milk into the diet while observing for the return of symptoms.

Dr. Alicia Maddix is a resident pediatrician at Carolinas Medical Center and Dr. Erin Stubbs is a board-certified pediatrician at CMC Myers Park Pediatrics.