Food Allergy

  • Medical Author:
    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

  • Medical Editor: William C. Shiel Jr., MD, FACP, FACR
    William C. Shiel Jr., MD, FACP, FACR

    William C. Shiel Jr., MD, FACP, FACR

    Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

Quick GuideThe Most Common Food Allergies for Kids and Adults

The Most Common Food Allergies for Kids and Adults

What are food allergy risk factors?

Both adults and children may develop food allergies. Factors that increase one's risk of having a food allergy include the following:

  • Young age: Food allergies are most common in infants and toddlers.
  • Having a past food allergy as a child or an allergy to another food: Those who are allergic to one type of food are more likely to develop other food allergies. Adults who have outgrown food allergies they had as children are more likely to develop subsequent food allergies than people who have never had them.
  • Family or personal history of allergy, eczema, asthma, or hay fever increases the chances for developing a food allergy.

Do infants and children have problems with food allergy?

Most allergies to foods begin in the first or second year of life. While some of these reactions may resolve over time (such as allergies to cow's milk or eggs), other food allergies acquired in infancy (such as allergies to nuts or shellfish) typically persist throughout life. Allergies to milk or soy formula (a milk substitute made from soybeans) sometimes occur in infants and young children. These early allergies sometimes do not involve the usual hives or asthma but rather can cause symptoms in babies resembling infantile colic, and perhaps blood in the stool, or poor growth.

The clinical picture of infantile colic, which usually starts within one month of birth, is that of a crying child who sleeps poorly at night. The cause of colic is uncertain. A variety of psychosocial and dietary factors have been implicated, however, and allergy to milk or soy has been proposed as a cause of colic in a minority of infants with colic.

In infants, food allergy is usually diagnosed by observing the effect of changing the infant's diet; rarely, by using a food challenge. If the baby is on cow's milk, the doctor will suggest a change to soy formula or breast milk only, if possible. If the soy causes an allergic reaction, the baby can be placed on an elemental formula. These formulas are processed proteins and carbohydrates, basically amino acids and sugars, and contain few, if any, allergens.

Food protein-induced enterocolitis syndrome (FPIES) is a bowel condition that affects children and is sometimes referred to as a delayed food allergy. It often occurs in infants who are beginning to eat solid foods. Unlike a typical food allergy, the symptoms come on hours after a food is consumed. It is a serious illness accompanied by vomiting and diarrhea. In severe cases, dehydration and shock can result due to the fluid lost from diarrhea and vomiting. Milk, soy, and grains are the foods that most often trigger FPIES. Research has suggested that FPIES results from a different mechanism than the production of IgE antibodies seen with typical allergic reactions.

Breastfeeding: Exclusive breastfeeding, that is, excluding all other foods, for at least the first four months of life appears to help protect high-risk children against milk allergy and eczema in the first two years of life. Breast milk contains less protein that is foreign to the infant and, therefore, is less allergenic than cow's milk or soy formula. Exclusive breastfeeding should be a consideration, therefore, especially in infants who are predisposed to food allergy. Some children are so sensitive to a certain food, however, that if the mother eats that food, sufficient quantities enter the breast milk to cause a reaction to the food in the child. In this situation, the mothers themselves must avoid eating those foods to which the baby is allergic. No conclusive evidence has been obtained that suggests that breastfeeding prevents the development of allergies later in life.

Special considerations in children: An allergic child who itches, sneezes, and wheezes a lot can feel miserable and, therefore, sometimes misbehave or appear hyperactive. At the other extreme, children who are on allergy medicines that can cause drowsiness may become sleepy in school or at home. Parents and caregivers must understand these different behaviors, protect the children from the foods that induce their allergies, and know how to manage an allergic reaction, including how to administer epinephrine. Also, schools need to have plans in place to address emergencies, including anaphylactic shock.

Medically Reviewed by a Doctor on 2/24/2017

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