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Family Healthcare ResourceONLINE HEALTH AND MEDICAL INFORMATION |
ALLERGY REVIEW | Learn more about Allergy [Allergies] What is an allergy?An allergy refers to a misguided reaction by our immune system in response to bodily contact with certain foreign substances. When these allergens come in contact with the body, it causes the immune system to develop an allergic reaction in persons who are allergic to it. It is estimated that 50 million North Americans are affected by allergic conditions. The parts of the body that are prone to react to allergies include the eyes, nose, lungs, skin, and stomach. Common allergic disorders include: hay fever, asthma, allergic eyes, allergic eczema, hives, and allergic shock; all of which are discussed in the article. Most Prescribed Medications [Sorted by Popularity]Prednisone®, Deltasone®, Allegra®, Beconase AQ®, Hydroxyzine®, Vistaril®, Aristocort®, Atarax®, Diphenhydramine®, Benadryl®, Prednisolone®, Pediapred Oral Liquid, Medrol®, Loratadine®, Claritin®, Alavert®, Fluticasone propionate nasal inhaler-spray, Flonase®, Cetirizine®, Zyrtec®, Fexofenadine®, Allegra®, Chlorpheniramine®, Pseudoephedrine®, Deconamine®, Sudafed®, Promethazine®, Phen-Tuss®, Phenergan®, Cyproheptadine®, Rhinocort®, Flovent®, Cromolyn®, Flunisolide nasal spray, Nasacort®, Beclomethasone dipropionate inhaler, Vanceril®, Azelastine®, Astelin®, Desloratadine®, Clarinex®, Salmeterol®, Serevent® BUY ANTIALLERGY RX MEDICATIONSHow the immune system responds to allergies?Why certain people have an allergy? In fact, by far the most important indoor pollutant is a cigarette [tobacco smoke], which is bly associated with allergic sensitization, asthma, and other respiratory illnesses. Exposure to smoke results in the body's enhanced ability to produce IgE (the allergy antibody) that attaches to allergens (e.g. pollen, dust mites and dander). The IgE response is a key trigger of allergic reactions. Parental smoking increases the risk of their children having many respiratory illnesses, including bronchitis, chronic cough, and asthma. Smoking during pregnancy and breastfeeding results in a higher risk for the children to develop allergic eczema (atopic dermatitis). Does the air we breathe have an impact on the rising incidence of allergies and asthma? Hay fever was rare in Japan before World War II. However, pollen allergy is now common and mostly affects those living in Japanese cities and near highways. Allergic disease is also more common in highly developed countries in North America and Europe and less common in Third World countries. This suggests that there must be something about modern, urban life that promotes allergy. Let us examine the impact of air pollution. Allergy | what does it mean?Austrian pediatrician Clemens Pirquet (1874-1929) first used the term allergy. He referred to both immunity that was useful and to the harmful hypersensitivity as "allergy." The word allergy is taken from the Greek words "allos," meaning different or changed and "ergos," meaning work or action. Allergy roughly refers to an "altered reaction." The word allergy was first used in 1900s 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." An allergy refers to an exaggerated reaction by our immune system in response to bodily contact with certain foreign substances. It is exaggerated because these foreign substances are usually seen by the body as harmless and no response occurs in non- allergic people. Allergic people's bodies recognize the foreign substance and one part of the immune system is turned on. Allergy-producing substances are called "allergens." Examples of allergens include pollens, dust mite, molds, danders, and foods. 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 allergen comes in contact with the body, it causes the immune system to develop an allergic reaction in persons who are allergic to it. When you inappropriately react to allergens that are normally harmless to other people, you are having an allergic reaction and can be referred to as allergic or atopic. Therefore, people who are prone to allergies are said to be allergic or "atopic." What causes allergies?Allergy is caused by an oversensitive immune system, which leads to a misdirected immune response. Our immune system is the body's organized defense system against foreign invaders, particularly harmful substances, such as bacteria, viruses and infections. It works by recognizing and reacting to these foreign substances [allergens], which are called antigens, that are generally harmless and in most people do not cause any problem. Antigens are substances that are capable of causing the production of antibodies. Antigens may or may not lead to an allergic reaction. Allergens are certain antigens that cause an allergic reaction and the production of IgE. The immune system is designed to destroy the "enemy". One of the ways it does this is to create protective proteins called antibodies that are specifically targeted against particular foreign substances. These antibodies, or immunoglobulins (IgG, IgM, IgA, IgD), are protective and help destroy a foreign particle by attaching to its surface, thereby making it easier for other immune cells to destroy it. The allergic person however, develops a specific type of antibody called immunoglobulin E, or IgE, in response to certain normally harmless foreign substances, such as cat dander. To summarize, immunoglobulins are a group of protein molecules that act as antibodies. There are five different types; IgA, IgM, IgG, IgD, and IgE. IgE is the allergy antibody. In 1967, Kimishige & Teriko Ishizaka discovered a previously unrecognized type of immunoglobulin in allergic people. They called it gamma E globulin or IgE. So, what causes an allergy indeed? To help answer this question, let's look at a common household example. A few months after the new cat arrives in the house, dad begins to have itchy eyes and episodes of sneezing. One of the three children develops coughing and wheezing, especially when the cat comes into her bedroom. The mom and the other two children experience no reaction whatsoever to the presence of the cat. How can we explain this? In this example, the dad and the youngest daughter developed IgE antibodies in large amounts that were targeted against the cat allergen, the cat dander. The dad and daughter are now sensitized or prone to develop allergic reactions on subsequent and repeated exposures to cat allergen. Typically, there is a period of "sensitization" ranging from months to years prior to an allergic reaction. Although it might occasionally appear that an allergic reaction has occurred on the first exposure to the allergen, there must have been a prior contact in order for the immune system to be poised to react in this way. IgE is an antibody that all of us have in small amounts. Allergic persons, however, produce IgE in large quantities. Normally, this antibody is important in protecting us from parasites, but not from cat dander or other allergens. During the sensitization period, cat dander IgE is being overproduced and coats certain potentially explosive cells that contain chemicals. These cells are capable of causing an allergic reaction on subsequent exposures to the dander. This is because the reaction of the cat dander with the dander IgE irritates the cells and leads to the release of various chemicals, including histamine. These chemicals, in turn, cause inflammation and the typical allergic symptoms. This is how the immune system becomes exaggerated and primed to cause an allergic reaction when stimulated by an allergen. On exposure to cat dander, the mom and the other two children produce other classes of antibodies, none of which cause allergic reactions. In these non-allergic members of the family, the dander particles are eliminated uneventfully by the immune system and the cat has no effect on them. What person is at a high-risk group?Although you may inherit the tendency to develop allergies, you may never actually have symptoms. You also do not necessarily inherit the same allergies or the same diseases as your parents. It is unclear what determines which substances will trigger a reaction in an allergic person. Additionally, which diseases might develop or how severe the symptoms might be is unknown. Allergies can develop at any age, possibly even in the womb. They commonly occur in children but may give rise to symptoms for the first time in adulthood. Asthma may persist in adults while nasal allergies tend to decline in old age. Another major piece of the allergy puzzle is the environment. It is clear that you must have a genetic tendency and be exposed to an allergen in order to develop an allergy. Additionally, the more intense and repetitive the exposure to an allergen and the earlier in life it occurs, the more likely it is that an allergy will develop. There are other important influences that may conspire to cause allergic conditions. Some of these include smoking, pollution, infection, and hormones. Common allergic symptoms and their signsThe parts of the body that are prone to allergies include the eyes, nose, lungs, skin, and stomach. Although a variety of allergic diseases may appear different, they all result from an exaggerated immune response to foreign substances in sensitive people. Allergy symptoms vary, but may include: Here's a brief review of common allergic disorders Allergic Rhinitis Allergic rhinitis ("hay fever") is the most common of the allergic diseases and refers to seasonal nasal symptoms that are due to pollens. Year round or perennial allergic rhinitis is usually due to indoor allergens, such as dust mites, animal dander, or molds. It can also be caused by pollens. Symptoms result from the inflammation of the tissues that line the inside of the nose (mucus lining or membranes) after allergens are inhaled. Adjacent areas, such as the ears, sinuses, and throat can also be involved. The most common symptoms include: Runny nose, Stuffy nose, Sneezing, Nasal itching (rubbing), Itchy ears and throat, Post nasal drip (throat clearing). Allergic AsthmaAsthma is a breathing problem that results from the inflammation and spasm of the lung's air passages (bronchial tubes). The inflammation causes a narrowing of the air passages, which limits the flow of air into and out of the lungs. Asthma is most often, but not always, related to allergies. Common symptoms include: Shortness of breath, wheezing, coughing, chest tightness. Allergic EyesAllergic eyes (allergic conjunctivitis) is inflammation of the tissue layers (membranes) that cover the surface of the eyeball and the undersurface of the eyelid. The inflammation occurs as a result of an allergic reaction and may produce the following symptoms: Redness under the lids and of the eye overall, watery, itchy eyes, swelling of the membranes. Allergic EczemaAllergic eczema (atopic dermatitis) is an allergic rash that is usually not caused by skin contact with an allergen. This condition is commonly associated with allergic rhinitis or asthma and features the following symptoms: Itching, redness, and or dryness of the skin, rash on the face, especially children, rash around the eyes, in the elbow creases, and behind the knees, especially in older children and adults. Allergic HivesHives (urticaria) are skin reactions that appear as itchy swellings and can occur on any part of the body. Hives can be caused by an allergic reaction, such as to a food or medication, but they also may occur in non-allergic people. Typical hive symptoms are: Raised red welts, intense itching. Hives are swollen, red or pink bumps, patches, or welts on the skin that usually appear suddenly. Itching is the most common symptom associated with hives, although some people report that hives cause a stinging or burning sensation. Hives are a very common reaction to all kinds of stimuli. While an allergic reaction can be a cause of hives, in the majority of outbreaks, the exact cause of hives is not known. Hives are also known as urticaria. Hives form when a chemical called histamine is released by specialized cells known as mast cells. It is true that allergic reactions ultimately lead to the release of histamine, but other circumstances can result in the release of histamine, causing an outbreak of hives. Histamine acts by causing blood vessels to leak fluid into the nearby tissues. In the skin, small areas of swelling develop as a result of capillary (the smallest blood vessels) leakage. In addition to allergic reactions to medications, foods, or other substances, hives may be triggered by direct physical stimulation such as temperature extremes, water, sun, and physical exercise. Having a viral infection can also cause an outbreak of hives, and even stress and nervousness have been associated with hives outbreaks. In the form of hives known as dermographia, or "skin writing," raised, itchy red welts with adjacent flares appear wherever the skin is scratched or where belts and other articles of clothing rub against the skin. Most outbreaks of hives resolve on their own. The hives may last for just a few minutes, a few hours, or they may persist for days. Treatment of hives is directed toward relieving the unpleasant symptoms, mainly itching. Over-the-counter or prescription antihistamine medications are useful in relieving the itch, and creams or ointments that contain antihistamines or medications that reduce signaling from the nerve endings in the affected skin can also provide relief. In addition to medications, applying cool compresses to the affected area and wearing light, loose-fitting clothing can help ease the discomfort of hives. Allergic ShockAllergic shock (anaphylaxis or anaphylactic shock) is a life-threatening allergic reaction that can affect a number of organs at the same time. This response typically occurs when the allergen is eaten (for example, foods) or injected (for example, a bee sting). Some or all of the following symptoms may occur: Hives or reddish discoloration of the skin, nasal congestion, swelling of the throat, stomach pain, nausea, vomiting, shortness of breath, wheezing, low blood pressure or shock. Allergic BreathingBreathing can be hazardous if you are allergic. Aside from oxygen, the air contains a wide variety of particles; some toxic, some infectious, and some "innocuous," including allergens. The usual diseases that result from airborne allergens are hay fever, asthma, and conjunctivitis. The following allergens are usually harmless, but can trigger allergic reactions when inhaled by sensitized individuals. Pollens: trees, grasses, and/or weeds; Dust mites; Animal proteins: dander, skin, and/or urine; Mold spores; Insect parts: cockroaches. Allergic Food & DrugsWhen foods or medications are ingested, allergens may gain access to the blood stream and become attached to specific IgE on cells in remote sites such as the skin or nasal membranes. The ability of allergens to travel explains how symptoms can occur in areas other than the gastrointestinal tract. Food allergy reactions may begin with tongue or throat swelling and may be followed by tingling, nausea, diarrhea, or stomach cramps. Nasal breathing difficulties or skin reactions may also be seen. The two main allergen groups that are ingested are: Foods; Drugs (when taken by mouth): for example, antibiotics and aspirin; Allergy Assist The most common foods that cause allergic reactions are cow's milk, fish, shellfish, eggs, peanuts, tree nuts, soy, and wheat. Allergic SkinAllergic contact dermatitis does not involve IgE antibody, but involves cells of the immune system which are programmed to react when triggered by a sensitizing allergen. Touching or rubbing a substance to which you were previously sensitized can trigger a skin rash. Allergic contact dermatitis is an inflammation of the skin that is caused by a local allergic reaction. The majority of these localized skin reactions do not involve IgE, but are caused by cells of inflammation. The rash produced is similar to that of a poison ivy rash. It should be noted that when some allergens (for example, latex) come into contact with the skin, they are absorbed by the skin and can also potentially cause reactions throughout the body, not just the skin. For most people, however, the skin is a formidable barrier that can be only locally affected. Examples of allergic contact dermatitis include: Latex (causes IgE and non-IgE reactions); Plants (poison ivy and oak); Dyes; Chemicals; Metals (nickel); Cosmetics. Allergic InjectionsThe most severe reactions can occur when allergens are injected into the body and gain direct access to the blood stream. This access carries the risk of a generalized reaction, such as anaphylaxis, which can be life-threatening. The following are commonly injected allergens that can cause severe allergic reactions: Insect venom. Allergy TreatmentThe best way to reduce allergy symptoms is to try and avoid what causes your allergies in the first place. This is especially important for food and drug allergies. The most appropriate medication depends on the type and severity of symptoms. Specific illnesses that are caused by allergies (such as asthma, hay fever, and eczema) may require other treatments. Medications that can be used to treat allergies include: ExpectationsMost allergies can be easily treated with appropriate medications. Some children may outgrow an allergy. This is particularly true of food allergies. However, in general, once a substance has triggered an allergic reaction, it continues to affect the person. Allergy shots are most effective when used to treat those with hay fever symptoms and severe insect sting allergies. They do not work well for food allergies. Allergy shots may require years of treatment, but they work in about two-thirds of cases. However, they may cause uncomfortable side effects (such as hives and rash) and dangerous outcomes (such as anaphylaxis). PreventionChildren who have been breastfed are less likely to have allergies. In addition, a mother who avoids cow's milk, eggs, nuts, and peanuts while breastfeeding can prevent allergy-related conditions, including eczema, in some children. If there is a family history of eczema and allergies it is wise to discuss the implications for infant feeding with your child's doctor. The timing of introduction of solid foods in general, as well as of several specific foods, can help prevent some allergies. There is also evidence that infants exposed to certain airborne allergens (such as dust mites and cat dander) may be less likely to develop related allergies. This is called the "hygiene hypothesis" and sprang from observations that infants on farms tend to have fewer allergies than those who grow up in environments that are more sterile. Once allergies have developed, treating the allergies and carefully avoiding those things that cause reactions can prevent allergies in the future. Allergy related topicsAllergic Cascade, Allergy Treatment Begins At Home, Anaphylaxis, Asthma, Asthma in Children, Atopic Dermatitis, Chronic Rhinitis and Post-Nasal Drip, Cold, Flu, Allergy, Cosmetics Allergies, Chronic Cough, Diaper Rash, Eczema, Eustachian Tube Problems, Eye Allergy, Food Allergy, Hay Fever, Hives, Indoor Allergens, Insect Sting Allergies, Itchy Eyes, Latex Allergy, Pink Eye, Poison Ivy, Rash, Sinus Infection BUY ANTIALLERGY RX DRUGS ON LINEAllergy/Allergies contents
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