Food Allergies

  • Allergic reaction

    Allergic reaction

    Swollen upper lip of a six year-old boy who is experiencing an allergic reaction to peanuts. Eating peanuts has triggered an immune response in which the boy’s body is releasing chemical histamine. Histamine causes blood vessels to widen, fluids to leak into tissues and muscles to spasm. Symptoms can include rashes, itchy swelling, inflamed eyes or vomiting and diarrhea.

  • Urticaria


    Also known as nettle rash or hives, this skin inflammation is caused by a food allergy. In this case it was triggered by cereal.

  • Rash


    A red rash on the arm of a four-month old baby due to an allergic food reaction of unknown origin.

  • Angiodema


    Severe sudden swelling in the lower face of a 50-year-old man experiencing an allergic food reaction. Angioedema can cause difficulty with speaking and breathing, and can potentially block the windpipe and cause suffocation. Anti-inflammatory drugs are administered to treat angiodema.

  • Skin prick testing

    Skin prick testing

    This test is used to identify allergens that may be causing a patient’s allergic reaction. Small amounts of suspected allergy-causing substances are placed on the skin, which is then observed for signs of a reaction.

  • Food challenge

    Food challenge

    A double-blind oral food challenge in which a patient eats a variety of foods one by one, while being watched for symptoms of an allergic reaction by a doctor. The foods will include suspected allergens and placebos. Neither the patient, nor doctor, knows which foods are which. A food challenge is used after other tests, such as skin tests, to confirm an allergy.

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Food allergies are immune system reactions that many people experience after exposure to certain foods — particularly milk, eggs, peanuts and tree nuts — and can involve symptoms including digestive problems, hives or swollen airways. Some people experience severe, life-threatening anaphylaxis.

Food allergy is becoming more common among children, increasing 18% from 1997 to 2007, according to statistics from the American Academy of Asthma, Allergy and Immunology. The cause of the increase remains unknown, but several hypotheses to explain shifts in prevalence are currently being investigated.

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