Allergies in Children

What are allergies?

Allergies are overreactions of the immune system. They happen when the immune system fights harmless foreign substances called allergens, such as dust mites, pollen, pet dander, and food. Therefore, treatments are usually designed to suppress the allergic reaction so your child can be safely exposed to the allergens and/or treat the symptoms when they occur.

Visible allergy symptoms are the body’s reaction to inflammatory chemicals, such as histamines, cytokines, or leukotrienes. Inflammatory chemicals are released from white blood cells to fight foreign substances in the body. Each time your child sneezes or shows some symptom of an allergic reaction, her body is reacting to the allergen. Specifically, the immune system makes immunoglobin E (IgE) antibodies to the allergens, which causes mast cells to release chemicals such as histamines, cytokines, and leukotrienes to fight the allergens. Essentially, the reaction between the IgE and the allergen triggers an allergic reaction.

The process is similar for food allergies. One difference is that with a food allergy, a child is more likely to have dermatologic (skin symptoms) and gastrointestinal symptoms, such as cramps, nausea, and vomiting, than with an inhalant allergy.

What are some symptoms of an allergic reaction?

  • rhinitis: nasal stuffiness, sneezing, nasal itching, nasal discharge, itching in ears or roof of the mouth
  • allergic conjunctivitis: red, itchy, watery eyes
  • atopic dermatitis: red, itchy, dry skin
  • urticaria: hives or itchy welts
  • asthma: shortness of breath, coughing, wheezing
  • Food allergies can be life-threatening. It is important to know the symptoms of a food allergic reaction. See our section on food allergies for signs and symptoms.

What causes an allergic reaction?

Allergens can be breathed in through the air and enter the nose, sinuses, throat, or lungs. Additionally, allergens can enter through the skin with direct physical contact or can be ingested in the case of food allergies.

Some of the allergens that may trigger an allergic reaction are:

Patterns of allergies have been found in families; however, the specific genetic factors are not yet fully understood.

How we care for allergies

Boston Children’s Hospital's Allergy and Asthma Program physicians collaborate with your child’s primary care physician to provide a comprehensive and individualized treatment plan. To help treat individuals with severe atopic dermatitis, we have a multi-disciplinary Atopic Dermatitis Center with a psychologist and a nutritionist. Additionally, our team collaborates with Children’s researchers to conduct clinical trials to evaluate new approaches to allergy treatments.

What makes the Division of Immunology at Boston Children’s unique is the involvement of our researchers. Our scientists see patients, as well as conduct lab research, which helps to raise the level of patient care and brings innovative discoveries directly to our young patients.