Allergic Colitis

What is allergic colitis?

Allergic colitis is a condition in which your baby's immune system overreacts to the proteins found in cow's milk, leading to inflammation in the colon.

Babies differ in how sensitive they are to milk. Some have very few symptoms, and others might experience blood in the stools if a breast-feeding mother has even a small splash of milk in her morning coffee.

Allergic colitis isn't uncommon; it affects between two and 3 percent of infants. Babies from families with a history of food allergies, asthma, or environmental allergies seem to have a slightly higher risk of developing the condition.

Allergic colitis often has few symptoms, but may be associated with irritability, gassiness, and with blood or mucus in the stools can make eating very uncomfortable for a baby, so they may not get the nutrition they need.

What are the symptoms of allergic colitis?

While symptoms may not appear until a baby turns 6 months old, most babies show signs within the first two months of life. In most babies, the symptoms are mild, but occasionally may worsen.

A baby with allergic colitis may be extremely fussy, difficult to console, and develop flecks or streaks of blood in the stool. Some infants also have diarrhea and vomiting, and some may show other signs of allergies, such as nasal congestion or eczema. It's important to remember that allergic colitis falls on a spectrum — some babies are much more sensitive to milk protein (and have more severe symptoms) than others.

Many babies go through a period of reflux (spitting up food) in the first year of life, but babies with allergic colitis may have an especially hard time with reflux. Treating the colitis may lead to an improvement in the reflux, but some of the reflux maybe not be related to the allergy process.

What are the causes of allergic colitis?

Allergic colitis seems to be caused by a combination of changes to the mother's immune system during pregnancy and the immaturity of a baby's own immune system. But it's not yet known why some babies develop the condition and others don't.

There may be a hereditary component, since babies who come from families with a history of food allergies, asthma, or environmental allergies seem to be more likely to have allergic colitis.

How is allergic colitis diagnosed?

If your baby is extremely irritable and you notice vomiting and gassiness, it's a good idea to make an appointment to see a pediatrician. The doctor will check for blood in your baby's stool. This might be blood that can only be seen through a microscope. If blood is found, the symptoms are most likely caused by an allergic reaction.

What are the treatment options for allergic colitis?

Most of the time, when an infant has blood in the stool, it's caused by a milk allergy, which is very treatable. The mother is placed on a dairy-free diet (if she's breast-feeding) or the baby is switched to a hypoallergenic formula. It takes up to 72 hours for the mother's breast milk to become free of milk protein, so until you're ready to nurse again, your baby will be given a hypoallergenic formula.

Roughly 30 percent of babies who are allergic to cow's milk protein are also allergic to soy protein, so if your baby's symptoms don't clear up, it is recommended that a nursing mother avoid soy as well as dairy (or use a soy-free formula).

Keep in mind, even if your baby is no longer ingesting the proteins that are causing reactions in the intestine, the intestines still need to heal. That's why you may continue to notice blood in the stool for three to four weeks after starting a milk/soy-free diet. But you should notice that your infant seems to be feeling better — less irritable and less reluctant to feed and also may be putting on weight, which is a good sign.

How we care for allergic colitis

The Boston Children's Hospital Division of Gastroenterology, Hepatology and Nutrition has been treating children with GI conditions, like allergic colitis, for more than 65 years.