Food Allergy Glossary

See Epinephrine.
Anything that triggers an allergic reaction. See also food allergen and environmental allergen.
A food that has the properties to trigger an allergic reaction.
A doctor who specializes in the diagnosis and treatment of allergies. Some allergists have more knowledge of and experience with treating food allergies than others.
Amino acid
A basic building block for protein molecules.
An immediate, severe, and sometimes fatal allergic reaction that can cause respiratory failure or shock due to a severe drop in blood pressure.
Swelling that typically accompanies hives and may result in welts (particularly on the face and around the eyes), stomachache (if the selling is in the intestines), or restricted or obstructed breathing (due to swelling in the airway).
A good-guy protein that your body releases to attack what your immune system perceives as a threatening intruder. Unfortunately, when you have a food allergy, your body produces antibodies to perfectly harmless foods.
Anti-IgE antibody therapy
An allergy treatment that consists of IgG antibodies that bind with the IgE antibodies. IgG renders the IgE powerless and unable to trigger the massive release of histamines, which cause most symptoms. This therapy is still in the testing phase.
Medication that prevents the body’s release of histamine during an allergic reaction from affecting the tissues. Antihistamines do not stop the reaction but prevent the reaction from triggering some symptoms.
Of or relating to allergies or asthma. Atopic conditions include asthma, hay fever, and some types of eczema.
Atopic dermatitis
Eczema that’s triggered by or made worse by an allergic condition. See also Eczema.
Autoimmune disease
Any condition caused by the failure of the body’s immune system to function normally. In some cases, the autoimmune system overreacts, and in other cases, it under-reacts.
A device that enables patients to inject themselves with a pre-measured dose of medication, such as epinephrine. The two most common autoinjectors are the EpiPen and Twinject.
Avoidance diet
A food regimen designed to assist patients in steering clear of the foods that trigger reactions. The avoidance diet is the primary treatment approach for food allergies.
White blood cells that protect the body from invading bacteria and viruses but that are also involved in the immune system’s response to allergens. See also Mast cell.
Benadryl (Diphendydramine)
An antihistamine that’s one of the more effective medications in treating food allergy reactions. In the event of a severe reaction, however, Benadryl may not be effective, and epinephrine is required.
Complementary treatments
Any therapy that contributes to relieving symptoms but is not sufficient, in and of itself, to effectively treat a condition.
A steroid-based medication, such as prednisone, that can help prevent a recurrence of symptoms in the hours following a severe reaction and prevent late reactions, but that don’t work rapidly enough to provide immediate relief.
Cross contamination
A situation in which a safe food is tainted with allergens from an unsafe food. Cross contamination can occur when a safe food is manufactured on the same equipment as an unsafe food, when safe food is prepared or served with tainted utensils, or when an unsafe food drops, splashes, or splatters into a safe food.
Cytotoxic testing
Any of several unproven methods of diagnosing allergies by exposing blood cells to suspected allergens and then examining the changes in those cells under a microscope.
Double-blind test
A treatment study in which neither the researchers nor the patients know who’s receiving treatment and who’s not until after the study is completed. See also Open test and Single-blind test.
A persistent rash that is characterized by extreme dryness and itching of the skin and may or may not be caused by a food allergy. When food allergy is involved, the condition is commonly referred to as atopic dermatitis.
Inflammation of the small and large intestine, commonly producing symptoms of fever, abdominal swelling, diarrhea, food malabsorption, constipation, and abdominal pain.
Environmental allergen
Airborne particles, including dust, molds, and pollens that trigger allergic reactions in some individuals.
A catalyst (speeder-upper) for the body’s chemical reactions. In cases of food intolerance, you may be lacking an enzyme necessary for digesting a particular food.
Eosinophilic esophagitis
Inflammation of the esophagus often accompanied by pain, reflux, poor appetite, and difficulty swallowing.
Eosinophilic gastroenteritis
A chronic inflammation in the GI tract, sometimes localized and sometimes involving the entire GI tract. Eosinophilic gastroenteritis may or may not be related to food allergy and when it is, it’s usually not IgE-mediated. See also Eosinophilic esophagitis and IgE-mediated food allergy.
Another name for adrenaline, epinephrine is often administered via a shot during a severe allergic reaction to quickly alleviate symptoms.
An ancient Chinese herbal formula that has proven somewhat effective in virtually curing peanut allergy in mice.
A variant of this FAHF-1 that has proven as effective in treating peanut allergy in mice but is considered safer.
False negative
A test result that mistakenly shows that you’re not allergic to something you really are allergic to.
False positive
A test result that mistakenly shows that you’re allergic to something you’re really not allergic to. False positives often convince some doctors to overly restrict a patient’s diet.
Food allergen
A substance in a food, typically a protein, that triggers the immune system to overreact.
Food allergy
A condition that results when the body’s immune system mistakenly identifies a particular food as an evil invader. Not to be confused with food intolerance.
Food challenge
An allergy test that consists of the patient consuming the food that the patient is suspected of being allergic to. Food challenges should be performed only under a qualified doctor’s supervision and with emergency medications and equipment readily available.
Food intolerance
An inability of the body to digest a particular food or component of that food, typically due to the lack of an enzyme required to break down the food.
Food poisoning
The introduction of a poisonous substance, bacteria, virus, parasite, or other toxin into the body, often causing flu-like symptoms, including nausea, vomiting, and diarrhea.
Gastroesophageal reflux disease (GERD)
Irritation or inflammation of the esophagus often caused by stomach acid backing up on the esophagus. Food allergy plays a role in up to one-third of cases of GERD in infants and may be the sole cause of the reflux in these cases.
Genetically engineered immunization shots
A treatment still in the testing phase that’s designed to re-train the immune system to function properly by ramping up its response to disease-causing organisms and cranking down its response to food allergens.
The protein in wheat and other grains that commonly triggers reactions in those with Celiac disease.
H2 blockers
A class of antihistamines, including Zantac (ranitidine) and Tagament (cimetidine), that are often effective when combined with antihistamines in the H1 class, such as Benadryl.
A substance that your body produces during an allergic reaction that triggers the most symptoms, including runny nose, swelling, hives, and rashes. Histamine swells the blood vessels and makes them highly permeable.
Histamine poisoning
A condition in which enough histamine is ingested to produce symptoms very similar to those that appear during an allergic reaction. Several foods, including strawberries, chocolate, wine, and beer, may contain enough histamines to cause allergy-like symptoms.
See Urticaria.
Hygiene hypothesis
A theory that attributes the increasing incidence of food allergies in more developed countries over the past 20 years to the fact that people in developed countries are more obsessed with proper hygiene. The theory proposes that the less the immune system is exposed to germs and bacterial by-products the more energy it has to unleash on allergens.
A product that’s been produced to contain as few allergens as possible and is less likely to trigger an allergic reaction.
IgE-mediated food allergy
A food allergy in which the immune system produces IgE antibodies that trigger symptoms. Doctors can test the levels of IgE in your system to determine the likelihood that you’re actually allergic to a specific food. See also Non-IgE-mediated food allergy.
Immune system
The body’s defense system against bacteria, viruses, and anything else it identifies as an enemy invader. Unfortunately for those with food allergies, the immune system identifies one or more foods as harmful.
Immunoglobulin E (IgE)
One of your body’s antibodies that the immune system commonly releases during its overreaction to an allergenic food. Allergists often test for the presence of IgE in order to diagnose or rule out an allergy to a particular substance.
Any of various treatments designed to make the immune system more tolerant of allergens. Immunotherapy often consists of exposing the immune system to gradually increasing doses of the allergen over time.
The enzyme required to break down lactose (milk sugar).
Lactose intolerance
An inability to digest milk sugar that triggers symptoms often mistakenly attributed to food allergy.
Leaky gut syndrome
A condition in which the walls of the intestines enable undigested food particles to pass through. Leaky gut syndrome is often mistakenly identified as a potential cause of food allergies.
White blood cells that that are the key to the immune system’s response to defend the body against whatever the immune system identifies as a threat.
Mast cell
An immune system cell that releases histamine when an allergen enters the body, resulting in the most common allergy symptoms. See also Basophils.
Non-IgE-mediated food allergy
A food allergy in which symptoms are not triggered by the presence of higher than normal concentrations of IgE antibodies. Non-IgE-mediated food allergies typically produce symptoms that appear more gradually and last longer, such as gastro-intestinal problems.
Open test
A treatment study in which researchers and patients know who’s receiving treatment and who’s not. Because everyone is aware of what’s going on, results may be influenced by the placebo effect. See also Double-blind test and Single blind test.
Oral allergy syndrome
A reaction restricted to the lips and mouth and is characterized by itching (sometimes severe) and swelling (usually mild). Oral allergy syndrome is most often caused by allergies to fresh fruits and vegetables in people with severe pollen allergies.
Beneficial bacteria, such as those found in yogurt, that may optimize the functioning of the immune system, improving its ability to defend the body against harmful bacteria and viruses while decreasing its tendency to overreact to food allergens.
Inflammation, itching, or soreness around the rectum which may or may not be related to food allergy. When it is related to food allergy, it’s called allergic proctitis.
An assemblage of amino acid chains that’s present in foods and throughout the body. Foods that cause allergic reactions commonly contain proteins that the immune system mistakenly identifies as dangerous.
Short for radioallergosorbent test, RAST is a blood test that helps diagnose the presence of IgE antibodies to specific foods. RASTs can help your doctor identify or rule out particular food allergies, but RAST results are not always conclusive. (Sometimes referred to as called the CAP-RAST or ImmunoCap test, which are the RASTs that have been best tested for the diagnosis of food allergy.)
Rotation diet
A treatment approach that consists of avoiding certain foods or food groups on a temporary basis. Rotation diets are not considered a primary treatment for people with food allergies, especially those who experience severe reactions.
The process by which a genetic susceptibility to an allergy develops into an actual allergy through one or more exposures to an allergen.
Single-blind test
A treatment study in which researchers know who’s receiving treatment and who’s not, but the patients don’t. Because the researcher may unknowingly communicate, through body language, who’s getting treatment and who’s not, single-blind testing may also be influenced by the placebo effect. See also Double-blind test and Open test.
Skin test
An allergy test in which suspected allergens are placed below the top layer of skin to determine whether the body reacts to the substance.
A substance found in relatively high concentrations in some wines and food additives, including MSG (monosodium glutamate), that can cause chemical reactions in the body that produce symptoms very similar to those that appear in allergic reactions.
Fancy name for hives—reddish raised itchy areas that form on the skin often as the result of an allergic reaction, or a variety of other causes.