Allergy

Allergy involves an exaggerated response of the immune system, often to common substances such as foods or pollen. The immune system is an intricate system that defends the body against foreign invaders, such as bacteria and viruses, while also surveying for conditions such as cancerand autoimmunity. Allergens are substances that are foreign to the body and can cause an allergic reaction. IgE is the allergic antibody. Allergies can not only develop at any age, but many individuals also outgrow allergies over time. A person has a greater risk of developing allergic conditions if there is a family history of allergy, especially in their parents or siblings, but the environment also plays a role.

In this review you will learn how allergy relates to the immune system. You will begin understanding how and why certain people become allergic. The most common allergic diseases are discussed briefly in this article.

An allergy refers to an exaggerated reaction by our immune system in response to exposure to certain foreign substances. It is exaggerated because these foreign substances are usually seen by the body as harmless and no response occurs in nonallergic people. In allergic individuals, the body recognizes the foreign substance and one arm of the immune system generates a response.

Allergy-producing substances are called "allergens." Examples of allergens include pollens, dust mites, molds, animal proteins, foods, and even medications. To understand the language of allergy it is important to remember that allergens are substances that are foreign to the body and can cause an allergic reaction in certain people. When an allergic individual comes in contact with an allergen, the immune system mounts a response through the IgE antibody. Therefore, people who are prone to allergies are said to be allergic or "atopic."

Austrian pediatrician Clemens Pirquet (1874-1929) first used the term allergy. He referred to both immunity that was beneficial and to the harmful hypersensitivity as "allergy." The word allergy is derived from the Greek words "allos," meaning different or changed and "ergos," meaning work or action. Generally speaking, allergy therefore refers to an "altered reaction." The word allergy was first used in 1905 to describe the adverse reactions of children who were given repeated shots of horse serum to fight infection. The following year, the term allergy was proposed to explain this unexpected "changed reactivity."

Allergy facts:

Approximately 10% to 30% of individuals in the industrialized world are affected by allergic conditions, and this number is increasing. Allergic rhinitis(nasal allergies) affects roughly 20% of Americans. Between prescription costs, physician visits, and missed days of work/school, the economic burden of allergic disease exceeds $3 billion annually. Asthmaaffects roughly 8% to 10% of Americans. The estimated health costs for asthma exceed approximately $20 billion annually. The prevalence of allergic conditions has increased significantly over the last two decades and continues to rise. Reviewed by William C. Shiel Jr., MD, FACP, FACR on 7/2/2013

Allergies - Describe Your Experience Question: Please describe your experience with allergies. Allergies - Symptoms Question: What symptoms did you experience with your allergies? Allergies - Causes Question: What causes your allergy symptoms? What are you allergic to? Allergies - Asthma Question: Do you have asthma along with your allergies? Allergies - Food Question: Have you ever experienced anaphylaxis due to a food allergy?

Medical Reviewer: Melissa Conrad Stoppler, MD

Allergies are exaggerated immune responses to environmental triggers known referred to as allergens.

Eczema Eczema, also known as dermatitis, is a general term for many types of skin inflammation. The most common form of eczema is atopic dermatitis. The otherPoison Ivy Poison ivy, oak, and sumac are plants that cause an itchy skin rash and skin inflamation when contacted directly. This poison can be treated with medicationsRash The word "rash" means an outbreak of red bumps on the body. The way people use this term, "a rash" can refer to many different skin conditions. The mostPink Eye Pink eye, also called conjunctivitis, is redness or irritation of the conjunctivae, the membranes on the inner part of the eyelids and the membranes coveringSinus Infection Sinus infection (sinusitis) signs and symptoms include headache, fever, and facial tenderness, pressure, or pain. Treatments of sinus infections are generallyVitamin D Deficiency Vitamin D deficiency has been linked with rickets, cancer, cardiovascular disease, severe asthma in children and cognitive impairment in older adults.Hives Hives, also called urticaria, is a raised, itchy area of skin that is usually a sign of an allergic reaction. The allergy may be to food or medications,Itching Itching can be a common problem. Itches can be localized or generalized. There are many causes of itching to include: infection (jock itch, vaginal itch),Bee and Wasp Sting Bees, wasps, and fire ants are related insects that belong to the Hymenoptera order. There are thousands of species of wasps found throughout the world.Chronic Rhinitis and Post-Nasal Drip Allergic rhinitis symptoms include an itchy, runny nose, sneezing, itchy ears, eyes, and throat. Seasonal allergic rhinitis (also called hay fever) isFood Allergy The most common food allergies are to eggs, nuts, milk, peanuts, fish, shellfish, strawberries and tomatoes. Symptoms and signs include nausea, vomiting,Atopic Dermatitis Eczema is a general term for many types dermatitis (skin inflammation). Atopic dermatitis is the most common of the many types of eczema. Other types ofEye Allergy Eye allergy (or allergic eye disease) are typically associated with hay fever and atopic dermatitis. Medications and cosmetics may cause eye allergies.Mold Mold exposure may cause symptoms in people who are sensitive to molds. Symptoms of mold allergy include sneezing, runny nose, wheezing, coughing, rednessHoarseness Hoarseness (abnormal deep, harsh, raspy voice) is caused by a variety of conditions in which the larynx (voice box and vocal chords) are irritated or injured.Bug Bites and Stings Bug bites and stings have been known to transmit insect-borne illnesses such as West Nile virus, Rocky Mountain spotted fever, and Lyme disease. ThoughAsthma Asthma is a common disorder in which chronic inflammation of the bronchial tubes (bronchi) makes them swell, narrowing the airways. Signs and symptomsBlepharitis Blepharitis is inflammation of the eyelids. Acne rosacea, Staphylococcal bacteria, allergies, sensitivities to makeup or contact lens solutions, head lice,Sinus Headache Sinus headache is caused by a sinus infection or inflammation of the sinus cavities. The primary symptom of a sinus infection is pain and increasing pressureColic in Babies Colic is crying or fussing that begins suddenly, lasting for a total of three hours a day and happening more than three days a week for about three weeks.Bad Breath Bad breath can result from poor oral hygien habits and may be a sign of other health problems. Bad breath, also called halitosis, can be made worse byAnaphylaxis Anaphylaxis is a serious allergic reaction that affects a number of different areas of the body at one time, and can be fatal. Causes of anaphylaxis canDry Skin Dry skin (xeroderma) may be caused by external factors, like cold temperatures, low humidity, harsh soaps, and certain medications, or internal factors,Hay Fever Hay fever (allergic rhinitis) is an irritation of the nose caused by pollen and is associated with the following allergic symptoms: nasal congestion, runnyIntertrigo Intertrigo is irritant dermatitis, usually found in skin folds, that is caused by rubbing, increased temperature, and moisture. Symptoms and signs includeSick Building Syndrome Multiple chemical sensitivity (MCS) or also referred to as sick building syndrome or environmental illness is the name given by some to a condition inInsect Sting Allergies The majority of stinging insects in the United States are from Bees, Yellow Jackets, Hornets, Wasps and Fire Ants. Severity of reactions to stings variesAsthma in Children Asthma, the main cause of chronic illness in children, has signs and symptoms in children that include frequent coughing spells, low energy while playing,Eye Care Many common eye disorders resolve without treatment and some may be managed with over-the-counter (OTC) products. It's important to visit a physician orSee All Related Diseases & Conditions ? ? var nl_tracking = 'cu-btm-allg_nwl'; function adjustForm() { $('#nl_module_1 iframe').contents().find('#email').css('width', '230px'); $('#nl_module_1 iframe').contents().find('#lid').val('45494'); }

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