44 Fun Facts About Allergies

What are normally harmless substances, such as pollen, that provoke hypersensitivity reactions called?

Allergens are typically harmless substances that can cause an allergic reaction in sensitive individuals, such as pollen, dust mites, or certain foods.

What is the most common immediate treatment for a severe allergic reaction?

Epinephrine is the first-line treatment for anaphylaxis, a severe and potentially life-threatening allergic reaction, and works quickly to reverse symptoms.

Which antibody is primarily responsible for mediating allergic reactions?

Immunoglobulin E (IgE) antibodies are key players in allergic reactions, binding to mast cells and basophils and triggering the release of inflammatory mediators like histamine upon allergen exposure.

What common environmental allergen comes from trees, grasses, and weeds?

Pollen from trees, grasses, and weeds is a widespread outdoor allergen, causing seasonal allergic rhinitis, commonly known as hay fever.

Hay fever in Japan is caused primarily by pollen from which tree?

Sugi, the Japanese cedar, was planted en masse after World War II for timber, and its spring pollen now triggers hay fever in a large share of the country's population.

What type of cells release histamine during an allergic reaction?

Mast cells are immune cells that store histamine and other inflammatory mediators in granules, releasing them upon activation during an allergic response.

Which chronic skin condition, often linked with allergies, is marked by itchy, red, dry and inflamed patches?

Eczema, or atopic dermatitis, is chronic inflammation of the skin that leaves it itchy, red, swollen and cracked, and it often goes hand in hand with allergies.

Which common food allergen is a legume?

Despite their name, peanuts are botanically legumes, not tree nuts, and are one of the most common and potent food allergens.

Which food became the ninth mandatory allergen on US food labels in 2023?

The FASTER Act of 2021 added sesame to the eight allergens already required on US labels; the EU list is longer and includes celery, mustard, and lupin.

What common allergic symptom involves persistent itching and inflammation of the nasal passages?

Allergic rhinitis, or hay fever, is characterized by symptoms such as a runny nose, sneezing, nasal congestion, and itchy nose and eyes, often triggered by airborne allergens.

What is the primary purpose of an antihistamine medication?

Antihistamines primarily work by blocking the action of histamine at its receptors, thereby reducing allergic symptoms like itching, sneezing, and runny nose.

Which allergy causes mouth and throat itching immediately after eating certain raw fruits or vegetables?

Oral Allergy Syndrome (OAS), also known as Pollen-Food Allergy Syndrome, is a type of contact allergic reaction in the mouth and throat that occurs when proteins in certain raw fruits, vegetables, or nuts cross-react with pollen antibodies.

How do dust-mite and pet-dander allergies typically differ from pollen allergies?

Perennial allergies occur year-round because indoor allergens such as dust mites, pet dander and mould never go away, unlike seasonal allergies tied to outdoor pollen.

Which type of medication is the preferred first-line treatment for persistent allergic rhinitis, working by reducing inflammation in the nose?

Nasal steroid sprays are often the first-line treatment for nasal allergy symptoms because they effectively reduce inflammation in the nasal passages, providing relief from congestion, sneezing, and runny nose.

Which metal, common in cheap jewellery, coins, zips and buttons, causes an itchy contact rash in many people?

Nickel allergy is a common cause of allergic contact dermatitis, with rashes wherever skin touches nickel: most often the hands, face, or anywhere in contact with jewellery or metal buttons.

Which kind of pollen is the most common trigger of hay fever worldwide?

Ryegrass and timothy are the usual culprits. Ragweed dominates autumn allergies in North America, but grass pollen reaches the most sufferers overall.

What is the medical term for hives, an itchy rash characterized by raised, red welts on the skin?

Urticaria is the medical term for hives, which are itchy, raised, red, or skin-colored welts that appear on the skin as a symptom of an allergic reaction or other triggers.

What preservative compound in some foods and wines can trigger asthma-like symptoms in sensitive people?

Sulfites are sulfur-based compounds used as preservatives in various foods, beverages, and medications, and can cause asthma-like symptoms, especially in individuals with asthma.

What type of immunotherapy involves placing drops or tablets under the tongue to treat certain allergies?

Sublingual immunotherapy (SLIT) is a form of allergy treatment where allergen extracts are administered as drops or tablets under the tongue, offering a convenient alternative to injections.

Where should an epinephrine auto-injector such as an EpiPen be injected in an emergency, through clothing if necessary?

The middle of the outer thigh, over the vastus lateralis muscle, so the drug reaches muscle quickly; it can go straight through clothing.

Which microscopic allergen feeds on shed skin and thrives in warm, humid bedding and carpets?

Dust mites are common indoor allergens, microscopic arachnids that feed on shed human skin cells and thrive in warm, humid environments like bedding, upholstered furniture, and carpets.

Which chronic condition, in which inflamed and narrowed airways cause wheezing, is often allergic and managed with inhalers?

Asthma, especially allergic asthma, inflames and narrows the airways in response to allergens, causing wheezing, coughing and shortness of breath, often treated with inhalers.

What is the term for swelling beneath the skin, often around the eyes or lips, that can accompany hives?

Angioedema is a type of swelling similar to hives, but it occurs deeper under the skin, often around the eyes, lips, or genitals, and can be a serious symptom if it affects the throat or tongue.

What nickname is given to oral anaphylaxis caused by eating flour infested with tiny arachnids?

Opened bags of flour stored in warm, humid kitchens can become infested, and the resulting batter delivers a dose of allergen straight to the gut.

What is the characteristic habitual upward nose-rub of chronic hay fever sufferers called?

The allergic salute, sometimes called the nasal salute, is the gesture of wiping or rubbing the nose upwards with the fingers, palm or back of the hand.

What type of allergic reaction is triggered by consuming red meat, often linked to a tick bite?

Alpha-gal syndrome is a type of food allergy to red meat and other products made from mammals, where the reaction is triggered by a sugar molecule called alpha-gal, often introduced by a tick bite.

Montelukast treats allergic asthma and rhinitis by blocking receptors for which mediators?

Montelukast is a leukotriene receptor antagonist: it blocks cysteinyl leukotrienes, inflammatory mediators released by mast cells and eosinophils that narrow airways and boost mucus.

Which common allergy trigger grows both indoors and outdoors in damp environments?

Mold, a type of fungus, releases spores that can act as allergens and thrive in damp indoor and outdoor environments, triggering respiratory and skin allergy symptoms.

Which helper T-cell subset drives the IgE response behind most allergies?

Th2 cells drive allergy: their interleukin-4 and interleukin-13 push B cells to switch to IgE production, while their interleukin-5 recruits eosinophils.

Which common food allergen is often found in baked goods, pasta, and cereals?

Wheat is a common food allergen, especially in children, and is a staple ingredient in many processed foods like baked goods, pasta, and cereals.

Which blood test, originally a radioimmunoassay, measures IgE antibodies to specific allergens?

The Radioallergosorbent Test, RAST, detects specific IgE antibodies in the blood to determine what a person is allergic to.

Which common indoor allergen is made up of microscopic skin flakes and dried saliva?

Pet dander, consisting of tiny flakes of skin shed by animals, is a common indoor allergen that can trigger allergic reactions in sensitive individuals.

What is the typical duration of the build-up phase in subcutaneous immunotherapy (allergy shots)?

The build-up phase of subcutaneous immunotherapy (SCIT) typically lasts several months, during which the allergen dose is gradually increased until a maintenance dose is reached.

Which chronic allergic condition causes swallowing difficulty and food getting stuck in the esophagus?

Eosinophilic esophagitis (EoE) is a chronic allergic inflammatory disease of the esophagus characterized by the accumulation of eosinophils, often triggered by certain foods.

Loratadine and cetirizine, which cause less drowsiness than older antihistamines, belong to which generation?

Second-generation antihistamines, such as loratadine and cetirizine, are known for causing less drowsiness compared to older, first-generation antihistamines because they cross the blood-brain barrier less readily.

What is the scientific name for the common house dust mite allergen?

Dermatophagoides species, commonly known as house dust mites, are a primary source of indoor allergens, thriving in human dwellings.

Tropomyosin, the major allergen in house dust mites, is also the protein behind allergy to which food?

Because the muscle protein tropomyosin is so similar across arthropods, people sensitised to mites can react to shrimp, crab, and lobster too.

Which allergy, common among healthcare workers, is triggered by gloves, balloons and condoms?

Latex allergy is an immune system reaction to proteins found in natural rubber latex, which can cause symptoms ranging from skin irritation to severe anaphylaxis upon contact with latex products.

What does the epinephrine in an auto-injector do to counteract an anaphylactic reaction?

It works to constrict blood vessels and open airways: raising blood pressure through vasoconstriction, relaxing the airway muscles (bronchodilation) and increasing cardiac output.

Which diagnostic method is the 'gold standard' for confirming a food allergy?

The oral food challenge is considered the 'gold standard' for diagnosing food allergies, as it involves controlled ingestion of the suspected food under medical supervision to observe for an allergic reaction.

Allergic contact dermatitis from poison ivy is which type of hypersensitivity reaction?

Delayed hypersensitivity reactions, such as allergic contact dermatitis, manifest hours or days after allergen exposure, unlike immediate reactions like anaphylaxis.

Which exercise-triggered condition can progress from hives to a dangerous drop in blood pressure?

Exercise-induced anaphylaxis (EIA) is a rare but serious condition where physical activity triggers an allergic reaction, sometimes requiring the consumption of a specific food beforehand.

What term describes an immediate wheal-and-flare reaction where an allergen has touched the skin?

Contact urticaria is an immediate skin reaction characterized by hives, redness, and itching that occurs at the site of contact with an allergen.

In 1986 the US FDA banned adding sulfite preservatives to which category of food?

The 1986 ban covered fresh produce eaten raw: salad bars had been spraying sulfites on lettuce to keep it crisp, and a string of severe reactions in asthmatics forced the FDA to act.