Food Allergy Clinical Presentation and Diagnosis

Health problems associated with food allergies can involve the gastrointestinal system, the respiratory system, the skin, and the eyes. Persons with a food allergy may have difficulty breathing, or they may have problems with itching, rashes, swelling, nausea, or vomiting. A food allergy may also be a cause of asthma.

allergic reaction: immune system reaction against a substance that is otherwise harmless processed food: food that has been cooked, milled, or otherwise manipulated to change its quality gastrointestinal: related to the stomach and intestines respiratory system: the lungs, throat, and muscles of respiration, or breathing nausea: unpleasant sensation in the gut that precedes vomiting asthma: respiratory disorder marked by wheezing, shortness of breath, and mucus production

Antihistamines can give some relief of minor allergic reactions, such as skin irritation. For more severe reactions, administering a dose of epinephrine may halt life-threatening anaphylactic shock. [Erik Freeland/Corbis. Reproduced by permission.]

anaphylaxis: life-threatening allergic reaction, involving drop in blood pressure and swelling of soft tissues especially surrounding the airways diet: the total daily food intake, or the types of foods eaten prevalence: describing the number of cases in a population at any one time anxiety: nervousness elimination diet: diet in which particular foods are eliminated to observe the effect glucose: a simple sugar; the most commonly used fuel in cells

The symptoms of food allergy vary widely from person to person. Food allergies can also cause a severe clinical reaction known as anaphylaxis, which can result in death. Anaphylaxis may be characterized by throat and lip swelling, shortness of breath, sweating, itching, and feeling very faint.

Diagnosis of a food allergy usually involves a careful examination of the patient's symptom history. Other causes of symptoms must be ruled out, and in some instances the suspected food or foods will be eliminated from the diet to see if symptoms stop. Blood tests or skin tests may also be performed. One test sometimes used to diagnose food allergy is the doubleblind, placebo-controlled food challenge. This test involves giving a patient a capsule containing a suspected food allergen and a capsule without the allergen (the placebo) and seeing if either causes symptoms in a controlled clinical setting. The test is called double-blind because neither the patient nor the physician evaluating the symptoms is aware of which capsule contains the allergen at the time the testing occurs.

Food Allergies

Food Allergies

Peanuts can leave you breathless. Cat dander can lead to itchy eyes, a stuffy nose, coughing and sneezing. And most of us have suffered through those seasonal allergies with horrible pollen counts. Learn more...

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