Who Gets Allergies? ( courtecy;- medicineNet.com )

ARTICLE

Who Gets Allergies? ( courtecy;- medicineNet.com  )

Although many individuals outgrow allergies over time, allergies can also develop at any age, including during adulthood Drug Allergy (Medication Allergy) Allergy facts Allergy involves an exaggerated response of the immune system, often to common substances such as foods or pollen. The immune system is a complex system that normally defends the body against foreign invaders, such as bacteria and viruses, while also surveying for abnormal changes in an individual’s own cells, such as cancer. Allergens are substances that are foreign to the body and that cause an allergic reaction. IgE is the allergic antibody. Although many individuals outgrow allergies over time, allergies can also develop at any age, including during adulthood. While the environment plays a role in the development of allergy, there is a greater risk of developing allergic conditions if a person has a family history of allergy, especially in parents or siblings. Allergy overview This is a review regarding how the allergic response of the immune system occurs and why certain people become allergic. The most common allergic diseases are described, including allergic rhinitis (nasal allergies), allergic conjunctivitis (eye allergies), allergic asthma, urticaria (hives), and food allergies. What is an allergy?   An allergy refers to an exaggerated reaction by the immune system in response to exposure to certain foreign substances. The response is exaggerated because these foreign substances are normally seen by the body as harmless in nonallergic individuals and do not cause a response in them. In allergic individuals, the body recognizes the foreign substance, and the allergic part 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 medications. When an allergic individual comes in contact with an allergen, the immune system mounts a response through the IgE antibody. People who are prone to allergies are said to be allergic or "atopic." Peanut Allergy Symptoms and Signs Types of peanut allergy symptoms: About 80%-90% of reactions involve skin manifestations such as a rash, including hives, redness, itching. Nevertheless, reactions can occur in the absence of a rash, and these reactions may be the most severe. Read more about the symptoms and signs of peanut allergies » What is an allergy? (Continued) Allergy prevalence: Approximately 10%-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. Asthma affects roughly 8%-10% of Americans. The estimated health costs for asthma exceed approximately $20 billion annually. Food allergies affect roughly 3%-6% of children in the United States, and roughly 1%-2% of adults in the U.S. The prevalence of allergic conditions has increased significantly over the last two decades and continues to rise. What causes allergies?  Readers Comments 8  Share Your Story A common scenario can help explain how allergies develop. 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. The mom and the other two children experience no reaction whatsoever despite the presence of the cat. How can this occur? The immune system is the body's organized defense mechanism against foreign invaders, particularly infections. Its job is to recognize and react to these foreign substances, which are called antigens. Antigens often lead to an immune response through the production of antibodies, which are protective proteins that are specifically targeted against particular antigens. These antibodies, or immunoglobulins (IgG, IgM, and IgA), 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. Other antigens, such as bacteria, do not lead to production of IgE, and therefore do not cause allergic reactions. Once IgE is formed, it can recognize the antigen, such as cat dander, and can then trigger an allergic response. IgE was discovered and named in 1967 by Kimishige and Teriko Ishizaka. s s What causes allergies? (Continued) In the pet cat example, the dad and the youngest daughter developed IgE antibodies in large amounts that were targeted against the cat allergen. The dad and daughter are now sensitized or prone to develop allergic reactions on repeated exposures to cat allergen. Typically, there is a period of "sensitization" ranging from days to years prior to an allergic response. Although it might occasionally appear that an allergic reaction has occurred on the first exposure to the allergen, there needs to be prior exposure in order for the immune system to react. It is important to realize that it is impossible to be allergic to something that an individual has truly never been exposed to before, though the first exposure may be subtle or unknown. The first exposure can even occur in a baby in the womb, through breast milk, or through the skin. IgE is an antibody that all of us have in small amounts. Allergic individuals, however, generally produce IgE in larger quantities. Historically, this antibody was important in protecting us from parasites. In the example above, during a sensitization period, cat dander IgE is overproduced and coats other cells involved in the allergic response, such as mast cells and basophils, which contain various mediators, such as histamine. These cells are capable of leading to an allergic reaction on subsequent exposures to the cat allergen (cat dander). The cat protein is recognized by the IgE, leading to activation of the cells, which leads to the release of the allergic mediators mentioned above. These chemicals cause typical allergic symptoms, such as localized swelling, inflammation, itching, and mucus production. Once primed, or sensitized, the immune system is capable of mounting this exaggerated response with subsequent exposures to the allergen. On exposure to cat dander, whereas the dad and daughter produce IgE, the mom and the other two children produce other classes of antibodies, which do not cause allergic reactions. In these nonallergic members of the family, the cat protein is eliminated uneventfully by the immune system and the cat has no effect on them. Another part of the immune system, the T-cell, may be involved in allergic responses in the skin, as occurs from the oils of plants, such as poison ivy, poison oak, poison sumac, reactions to metal, such as nickel, or certain chemicals. The T-cell may recognize a certain allergen in a substance contacting the skin and cause an inflammatory response. This inflammatory response can cause itching, rash, and discomfort. Who is at risk for allergies and why? Allergies can develop at any age, but most food allergies begin at a young age, and many are outgrown. Environmental allergies can develop at any time. The initial exposure or sensitization period may even begin before birth. Individuals can also outgrow allergies over time. It is not fully understood why one person develops allergies and another does not, but there are several risk factors for allergic conditions. Family history, or genetics, plays a large role, with a higher risk for allergies if parents or siblings have allergies. There are numerous other risk factors for developing allergic conditions. Children born via Cesarean section have a higher risk of allergy as compared to children who are delivered vaginally. Exposure to tobacco smoke and air pollution increases the risk of allergy. Boys are more likely to be allergic than girls. Allergies are more common in westernized countries, and less common in those with a farming lifestyle. Exposures to antigens, use of antibiotics, and numerous other factors, some of which are not yet known, also contribute to the development of allergies. This complicated process continues to be an area of medical research. What are common types of allergic conditions, and what are allergy symptoms and signs?  Readers Comments 38  Share Your Story The parts of the body that are prone to allergic symptoms include the eyes, nose, lungs, skin, and gastrointestinal tract. Although the various allergic diseases may appear different, they all result from an exaggerated immune response to foreign substances in sensitive individuals. The following are brief descriptions of common allergic disorders. Allergic rhinitis (hay fever) Allergic rhinitis ("hay fever") is the most common of the allergic diseases and refers to nasal symptoms that are due to aeroallergens. Year-round, or perennial, allergic rhinitis is usually caused by indoor allergens, such as dust mites, animal dander, or molds. Seasonal allergic rhinitis is typically caused by tree, grass, or weed pollens. Many individuals have a combination of both seasonal and perennial allergies. Symptoms result from the inflammation of the tissues that line the inside of the nose after exposure to allergens. The eyes, ears, sinuses, and throat can also be involved. The most common symptoms include the following: Runny nose Stuffy nose Sneezing Itchy nose, eyes, ears, and throat Postnasal drip (throat clearing) In 1819, an English physician, John Bostock, first described hay fever by detailing his own seasonal nasal symptoms, which he called "summer catarrh." The condition was called hay fever because it was thought to be caused by "new hay." Subscribe to MedicineNet's Allergy and Asthma Newsletter By clicking "Submit," I agree to the MedicineNet Terms and Conditions and Privacy Policy. I also agree to receive emails from MedicineNet and I understand that I may opt out of MedicineNet subscriptions at any time. Asthma  Readers Comments 3  Share Your Story Asthma is a respiratory condition that results from inflammation and hyperreactivity of the airways, leading to recurrent, reversible narrowing of the airways. Asthma can often coexist with allergic rhinitis. Other common triggers include respiratory viral infections and exercise. Common symptoms include the following: Shortness of breath Wheezing Coughing Chest tightness Health Solutions From Our Sponsors Kept Your Wisdom Teeth? Therapy at Home? Allergic eyes (conjunctivitis) Allergic eyes (conjunctivitis) are 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, which are generally present in both eyes: Redness under the lids and of the eye overall Watery, itchy eyes Swelling of the membranes Eczema (atopic dermatitis) Eczema (atopic dermatitis) is a condition commonly found in infants. It tends to occur in individuals at risk for other allergic conditions (asthma and allergic rhinitis) but is not usually caused by direct allergen exposure. The rash results from a complicated inflammatory process. Common features include the following: Dry skin associated with significant itching Involvement of the face, behind the elbows, and behind knees, though the rash can occur anywhere Hives (urticaria) Hives (urticaria) are skin reactions that appear as red, raised, itchy welts and can occur on any part of the body. Short-lived (acute) hives are often due to an allergic reaction to a food or medication, though they also commonly result from a viral infection in children. Hives that recur over a longer period of time (chronic hives) are rarely due to an allergic reaction. Hive are characterized by raised, red, welts that resolve over hours to a day; intense itching (typically not painful); no residual marks or bruising upon resolution; and swelling (particularly of the lips, face, hands, and feet). Anaphylaxis  Readers Comments 1  Share Your Story Anaphylactic shock is a potentially life-threatening allergic reaction that can affect a number of organs at the same time. Allergens that typically lead to anaphylaxis are foods, medications, and venom (bee stings). Environmental allergens rarely lead to anaphylaxis. Some or all of the following symptoms may occur: Hives, present in 80%-90% of cases Nasal congestion, runny nose, itchy eyes Swelling of the tongue and/or throat Abdominal discomfort, nausea, vomiting, diarrhea Shortness of breath, wheezing, coughing Low blood pressure, leading to lightheadedness, passing out, or shock Anaphylactic shock is an emergent, life-threatening condition that occurs when blood vessels dilate excessively due to an allergic reaction, which causes a significant drop in blood pressure. This can result in inadequate blood flow to the organs in the body. Subscribe to MedicineNet's Allergy and Asthma Newsletter By clicking "Submit," I agree to the MedicineNet Terms and Conditions and Privacy Policy. I also agree to receive emails from MedicineNet and I understand that I may opt out of MedicineNet subscriptions at any time. Where are allergens? Allergens may be inhaled, ingested (eaten or swallowed), applied to the skin, or injected into the body either as a medication or inadvertently by an insect sting. The symptoms and conditions that result depend largely on the route of entry and the type of allergen. The chemical structure of allergens affects the route of exposure. Airborne pollens, for example, tend to have little effect on the skin. They are easily inhaled and will thus cause more nasal and respiratory symptoms with limited skin symptoms. When allergens are swallowed or injected, they may travel to other parts of the body and provoke symptoms that are remote from their point of entry. For example, allergens in foods may prompt the release of mediators in the skin and cause hives. The specific protein structure is what determines the allergen's characteristics. Cat protein, Fel d 1, from the Felis domesticus (the domesticated cat), is the predominant cat allergen. Each allergen has a unique protein structure leading to its allergic characteristics. In the air we breathe Aside from oxygen, the air contains a wide variety of particles, including allergens. The usual diseases that result from airborne allergens are hay fever, asthma, and conjunctivitis. The following allergens can trigger allergic reactions when inhaled by sensitized individuals. Pollens from trees, grasses, and/or weeds Dust mites Animal proteins, including dander, skin, and/or urine Mold spores Insect parts, especially from cockroaches From  In what we ingest Foods and medications can also cause allergic reactions, some of which can be severe. These reactions often start with localized tingling or itching and then may lead to rash or additional symptoms, such as swelling, nausea, vomiting, diarrhea, or difficulty breathing. Here are the two most common allergens that are ingested: Foods: The most common food allergens are cow's milk, eggs, peanuts, tree nuts, wheat, soy, shellfish, finned fish, and sesame. Cow's milk, egg, wheat, and soy allergies are most common in children and are often outgrown over time. The most common allergens in adults are peanut, tree nuts, and shellfish. It should be noted that gluten is not a common food allergy, and true gluten hypersensitivity, or celiac disease, is mediated by another type of antibody (not IgE but IgA) and also leads to a different host of symptoms (including chronic abdominal discomfort, nausea, vomiting, change in stool, anemia). Medications: Although any medication can cause an allergic reaction, common examples include antibiotics (such as penicillin), and anti-inflammatory agents, such as aspirin and ibuprofen. Notably, many individuals who think they are allergic to medications actually can tolerate the medication without difficulty. Touching our skin Contact dermatitis is an inflammation of the skin that is caused by local exposure to a substance. The majority of these localized skin reactions do not involve IgE but are caused by other inflammatory cells. A good example is poison ivy. Examples of substances that commonly cause contact dermatitis include the following: Plants (poison ivy, poison sumac, and poison oak) Dyes Chemicals Nickel and other metals Cosmetics Injected into our bodies The most severe reactions often occur when allergens are injected into the body and gain direct access to the bloodstream. This intravenous access carries the increased risk of a systemic reaction, such as anaphylaxis. The following are commonly injected allergens that can cause severe allergic reactions: Insect venom Medications Allergy shots What specialists treat people with allergies? Although primary-care physicians are well equipped to treat mild allergic symptoms, allergy/immunology physicians (allergists) treat individuals with more bothersome allergies. Many allergists treat both children and adults, but some are specialized to either patient group alone. How do health care professionals diagnose allergies? The diagnosis of allergies begins with a detailed history and physical examination. Many people with allergies have other family members with allergic conditions. In addition to the history and exam, skin testing and sometimes blood work (specific IgE levels) can help with the diagnosis of allergies. There are several important considerations when interpreting the results of this testing: For environmental allergies such as pets, dust mites, pollen, and molds, skin prick testing is the best test to help with diagnosis of allergy. Blood work looking for the allergic antibody (IgE) is less sensitive and may miss some allergies. For food allergy testing, the most important part of the diagnosis is the health history. Skin testing or blood work (specific IgE testing) should only be ordered if the history is suggestive of food allergy. Without a suggestive history, food allergy skin testing and blood work is not very specific and has a high rate of false positive results. For food allergy testing, ordering skin testing or blood work (specific IgE testing) for broad panels of foods is discouraged, given the high rate of false positive results. For drug allergy, the history is the most important element in diagnosis. The only antibiotic with validated skin testing is penicillin. Penicillin skin testing can be very helpful in determining if an individual is truly allergic to penicillin and related antibiotics. Blood work (specific IgE testing) is not particularly helpful for the diagnosis of drug allergies. Sometimes, such as with food allergy and drug allergy, despite a detailed history and appropriate testing, the diagnosis of allergy remains unclear. In these situations, it is appropriate to consider a “graded challenge,” which is the “gold standard,” or the best test, for the diagnosis of allergies. A graded challenge should always be performed with an allergist in a setting equipped to manage a severe allergic reaction, such as anaphylaxis. Subscribe to MedicineNet's Allergy and Asthma Newsletter By clicking "Submit," I agree to the MedicineNet Terms and Conditions and Privacy Policy. I also agree to receive emails from MedicineNet and I understand that I may opt out of MedicineNet subscriptions at any time. What are treatment options and medications for allergies? The treatment for allergies depends on the particular condition. Some general guidelines are as follows: Allergic rhinitis and conjunctivitis Environmental control measures: These have limited efficacy. For dust mites, it helps to decrease humidity in the home and wash bedding in hot water once weekly. For pets, avoidance is most effective. Cat allergen is airborne, so having a cat in the home will cause allergic symptoms. Keeping dogs out of the bedroom may help reduce symptoms. Bathing both cats and dogs may decrease the allergen burden somewhat. There is no such thing as a hypoallergenic dog, but hypoallergenic cats have been bred. For pollen, keeping windows closed and staying indoors on high pollen days may be helpful. Oral antihistamines Nasal antihistamines Topical ocular antihistamines Nasal corticosteroids Allergen immunotherapy (see below) Asthma Rescue inhalers Inhaled corticosteroids, inhaled corticosteroids/long-acting bronchodilator combinations, long-acting anti-muscarinic medications Oral maintenance medications (anti-leukotriene medications, theophylline) Injectable medications that must be administered at a medical facility Allergen immunotherapy (see below) Oral steroids Eczema (atopic dermatitis) Vigorous moisturization Topical corticosteroids Oral antihistamines to help control itching Immunosuppressive medications in severe cases Hives (urticaria) Oral antihistamines Oral steroids Injectable medications administered in a medical facility Immunosupressive medications in severe cases Anaphylaxis Epinephrine is the one and only treatment for anaphylaxis, which is a severe allergic reaction that can involve multiple body systems and is life-threatening. Epinephrine is administered with an auto-injector into the muscle in the lateral thigh. Up to 20%-30% of severe allergic reactions may require treatment with more than one dose of epinephrine, so individuals who carry epinephrine should ideally carry two auto-injectors. If an individual experiences anaphylaxis and uses epinephrine, they should call 911 to be appropriately monitored. Of note, antihistamines such as diphenhydramine (Benadryl) are not appropriate treatments of anaphylaxis. Allergen immunotherapy (allergy shots) Allergy shots have been shown to decrease symptoms of environmental allergies and asthma and may also be beneficial in eczema. Allergy shots should be prescribed by an allergist and should always be administered in a health care facility equipped to manage a serious allergic reaction (anaphylaxis). Allergy shots help make the body less sensitive to the culprit allergen, such as pets, dust mites, pollens, and molds. Recently, the FDA has also approved immunotherapy that can be administered with a tablet under the tongue (sublingual immunotherapy). To date, this is only available for grass and ragweed. Unlike allergy shots, sublingual immunotherapy can be administered at home because the risk of a severe allergic reaction is lower with sublingual therapy. Of note, although there is significant research being done in the area, immunotherapy is not routinely used to treat food allergies. The treatment of food allergy remains avoidance of the culprit food and management of accidental exposures with the appropriate medications. Are there home remedies for allergies? Although there is significant research examining the role of vitamins, herbal medications, and other therapies on the treatment of allergies, there are currently no proven home remedies that successfully treat allergies. What is the prognosis of allergies? People with allergies have an excellent prognosis. Many children outgrow allergies over time, particularly food and medication allergies, such as penicillin. On the other hand, allergies can develop at any age. Allergies should not affect life expectancy, and with proper management, the majority of individuals with allergies should maintain an acceptable quality of life. Is it possible to prevent allergies? With the increasing prevalence of allergic conditions, many studies have examined risk factors for allergies and how to modify these to potentially prevent allergies. The development of allergies results from a complex interplay between a person’s genetic make-up (genotype) and its interaction with the environment (phenotype). Having family members with allergic conditions increases the risk of allergy. Numerous environmental influences may also affect the development of allergy, such as breastfeeding, cesarean sections, diet during pregnancy, vitamin D levels, use of antibiotics, use of probiotics, animal exposures, pollutant exposure, and diet during infancy. Of all the factors studied to date, it appears that introducing highly allergic foods into the child’s diet before one year of age may decrease the risk of food allergy, particularly peanut allergy. Allergen immunotherapy (allergy shots) have also been shown to decrease the risk of developing future environmental allergies and asthma. Finding additional ways to prevent allergic conditions remains an active area of research. From  References CONTINUE SCROLLING FOR RELATED ARTICLE Hives (Urticaria & Angioedema) Hives facts Hives (medically known as urticaria) are red, itchy, raised welts on the skin that appear in varying shapes and sizes; each one characteristically lasts no longer than six to 12 hours. Although hives are very common, and their cause is often elusive. Hives can change size rapidly and move around, disappearing in one place and reappearing in other places, often in a matter of hours. Ordinary hives flare up suddenly. Occasionally hives are produced by direct physical stimulation by environmental forces like heat, cold, and sunlight. Treatment of hives is directed at symptom relief until the condition goes away on its own. Antihistamines are the most common treatment for hives. Hives typically are not associated with long-term or serious complications. Can Stress Cause Hives? Hives can also develop as a result of sun or cold exposure, infections, excessive perspiration, and emotional stress. The reason why stress seems to precipitate an outbreak of hives in many people is not completely understood but is likely related to the known effects of stress on the immune system. In many cases, the cause of hives in a given individual cannot be identified. Read more about causes of hives » What are hives (urticaria) and angioedema? What do hives look like?  Readers Comments 100  Share Your Story Hives (medically known as urticaria) appear on the skin as wheals that are red, very itchy, smoothly elevated areas of skin often with a blanched center. They appear in varying shapes and sizes, from a few millimeters to several centimeters in diameter anywhere on the body. It is estimated that 20% of all people will develop urticaria at some point in their lives. Hives are more common in women than in men. One hallmark of hives are their tendency to change size rapidly and to move around, disappearing in one place and reappearing in other places, often in a matter of hours. An individual hive usually lasts no longer than 24 hours. An outbreak that looks impressive, even alarming, first thing in the morning can be completely gone by noon, only to be back in full force later in the day. Very few skin diseases occur and then resolve so rapidly. Therefore, even if you have no evidence of hives to show the doctor when you get to the office for examination, the diagnosis can be established based upon the accurate recounting of your symptoms and signs. Because hives fluctuate so much and so fast, it is helpful to bring along a photograph of what the outbreak looked like at its most severe point. Swelling deeper in the skin that may accompany hives is called angioedema. This swelling of the hands and feet, as well as the face (lips or eyelids), can be as dramatic as it is brief. What causes hives and angioedema? Are hives contagious? Does stress cause hives? Hives appear when histamine and other compounds are released from cells called mast cells, which are normally found in the skin. Histamine causes fluid to leak from the local blood vessels, leading to swelling in the skin. Hives are very common and are not considered contagious. Although annoying, hives usually resolve on their own over a period of weeks and are rarely medically serious. Some hives may be caused by allergies to such things as foods, infections by different organisms, medications, food coloring, preservatives and insect stings or bites, and chemicals; but in the majority of cases, no specific cause is ever found. Although people may find it frustrating not to know what has caused their hives, maneuvers like changing diet, soap, detergent, and makeup are rarely helpful in preventing hives unless there is an excellent temporal relationship. Since hives most often are produced by an immune mechanism, the condition is not contagious. If an infectious disease were the cause of hives in a particular person then it is possible, but not likely, that an infected contact could develop hives. Having hives may cause stress, but stress by itself does not cause hives. What are the different kinds of hives? Hives fall into two categories on the basis of the time they have been present: acute urticaria (ordinary hives, which resolve after six to eight weeks) and chronic urticaria (that continues longer than six to eight weeks). Since hives are so common and acute urticaria, by definition, resolves spontaneously, physicians do not generally expend much time or expense to evaluate the cause of hives of less than eight weeks' duration. 10 Common Allergy Triggers Slideshow Pictures Take the Quiz on Allergies Nasal Allergy Relief Products Slideshow What are the signs and symptoms of ordinary hives? Ordinary hives flare up suddenly and usually for no specific reason. Welts appear, often in several places. They flare, itch, swell, and go away in a matter of minutes to hours, only to appear elsewhere. This sequence may go on from days to weeks. Most episodes of hives last less than six weeks. Although that cutoff point is arbitrary, cases of hives that last more than six weeks are often called "chronic." What are the risk factors and causes of ordinary hives? As noted above, many cases of ordinary hives are "idiopathic," meaning no cause is known. Others may be triggered by viral infections. A few may be caused by medications, usually when they have been taken for the first time a few weeks before. (It is less likely for drugs taken continuously for long periods to cause hives but certainly not impossible.) When a medication is implicated as a cause of hives, the drug must be stopped, since testing is rarely available to confirm the cause. In most cases, drug-induced hives will go away in a few days. If a drug is stopped and the hives do not go away, this is a strong indication that the medication was not the cause of the hives. Some medications, like morphine, codeine, aspirin, and other nonsteroidal anti-inflammatory drugs (NSAIDs, such as ibuprofen [Advil]), cause the body to release histamine and produce urticaria through nonallergic mechanisms. People with urticaria should avoid these medications. Despite the reputation of hives being an "allergic" condition, there is often no obvious connection to any provoking substance. In this situation, random allergy testing is not usually helpful. If you know what is causing your hives, then avoiding the cause, if possible. What are the causes of chronic hives? Chronic hives (defined as lasting six weeks or more) can last from months to years. The evaluation of this condition is difficult, and allergy testing and other laboratory tests are only occasionally useful in such cases. The accurate evaluation of this condition requires the patient to give his or her physician precise information regarding their complete medical history, personal habits, and oral intake. Occasionally, it may be necessary to limit specific foods or drugs for a time to observe any affect upon the skin condition. Certain systemic diseases and infections, including parasitic infestations, may occasionally present in the skin as hives. If an inciting cause can be determined, then specific treatments for that condition ought to be effective, or in the case of food or drug allergy, strict avoidance would be necessary. There are additionally rare forms of chronic urticaria that are produced when the patient makes antibodies against molecules on the surface of their own mast cells. There are tests available to identify this type of hives. Physical urticaria (for example, heat hives) is a type of chronic urticaria produced by physical stimuli. Common environmental provocations such as sunlight, water, cold, heat, exercise, and pressure occasionally induce hives. Dermographism, which literally means "skin writing," is a common cause of physical urticaria. This is an exaggerated form of what happens to anyone when their skin is scratched or rubbed; a red welt appears at the site of the scratch. In dermographism, 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, causing mast cells to leak histamine. Another common form of physically induced hives is called cholinergic urticaria. This produces hundreds of small, itchy bumps. These occur within 15 minutes of exercise or physical exertion and are usually gone before a doctor can examine them. This form of hives happens more often in young people. Are there other conditions that mimic hives? There are other rashes that may look like hives, but the fact that they remain stable and do not resolve within 24 hours is helpful in distinguishing them from hives. Such rashes may need to have a small specimen of skin removed and examined under the microscope (biopsy) to accurately determine the nature of the skin disease. When to visit the doctor If hives are making it difficult to sleep, then it may be necessary to see a physician. This would be especially important if you are taking nonprescription antihistamines. If your hives last longer than two months, it is also likely you will benefit from visiting a physician. What specialists treat hives? Some family physicians or internists may feel comfortable caring for patients with chronic urticaria. Most dermatologists and allergists are able to care for patients with urticaria. How do health care professionals diagnose and evaluate chronic urticaria? Blood tests, including a complete blood count (CBC) and erythrocyte sedimentation rate (ESR, a marker of inflammation), are all that is typically recommended for evaluation. What are hives treatment options? How to stop hives The goal of treating most cases of ordinary acute urticaria is to relieve symptoms while the condition goes away by itself. The most commonly used oral treatments are antihistamines, which help oppose the effects of the histamine leaked by mast cells. The main side effect of antihistamines is drowsiness. Many antihistamines are available without prescription, such as diphenhydramine (Benadryl), taken in doses of 25 milligrams, and chlorpheniramine (Chlor-Trimeton), taken in a dose of 4 milligrams. These can be taken up to three times a day, but because these medications can cause drowsiness, they are often taken at bedtime. Those who take them should be especially careful and be sure they are fully alert before driving or participating in other activities requiring mental concentration. Loratadine (Claritin, 10 milligrams) and fexofenadine (Allegra) are antihistamines available over the counter that are less likely to cause drowsiness. Also approved for over-the-counter use is hydroxyzine (Atarax, Vistaril), which causes drowsiness, and its breakdown product, cetirizine (Zyrtec, 10 milligrams), which is less sedating. Antihistamines that require a prescription include cyproheptadine (Periactin), which tends to cause drowsiness. A prescription antihistamine that causes little sedation is levocetirizine (Xyzal). Sometimes physicians combine these with other types of antihistamines called H2 blockers, such as ranitidine (Zantac) and cimetidine (Tagamet). This antihistamine list is not exhaustive. Physicians individualize treatment plans to suit specific patients and modify them depending on the clinical response. Oral steroids (prednisone, [Medrol]) can help severe cases of hives in the short term, but their usefulness is limited by the fact that many cases of hives last too long for steroid use to be continued safely. Other treatments have been used for urticaria as well, including montelukast (Singulair), ultraviolet radiation, antifungal antibiotics, agents that suppress the immune system, and tricyclic antidepressants (amitriptyline [Elavil, Endep], nortriptyline [Pamelor, Aventyl], doxepin [Sinequan, Adapin]). Evidence to support the benefit of such treatments is sparse. In ordinary cases, they are rarely needed. A new treatment now indicated for chronic urticaria is the monthly subcutaneous injection of a monoclonal antibody, omalizumab (Xolair), directed against the IgE receptor on human mast cells. Topical therapies for hives are available but are generally ineffective. They include creams and lotions which help numb nerve endings and reduce itching. Some ingredients which can accomplish this are camphor, menthol, diphenhydramine, and pramoxine. Many of these topical preparations require no prescription. Cortisone-containing creams (steroids), even strong ones requiring a prescription, are not very helpful in controlling the itch of hives. Applying cool compresses may help soothe the itch of a hives rash. What is the prognosis of hives? To know exactly what kind of hives one has, or to learn more about research into the immune basis of hives or about rarer forms of this condition, consult a physician. It is important, however, to keep in mind that most cases of urticaria are annoying, not serious, and almost always temporary. From  Health Solutions From Our Sponsors Kept Your Wisdom Teeth? Therapy at Home? Drug Allergy (Medication Allergy) Drug allergy definition What are the signs and symptoms of an allergy to drug (medication) allergy? To what types of drugs are people most allergic? Is there a test for drug (medication) allergies? What is the treatment for a drug (medication) allergy? What should I do if I have an allergic reaction to a drug? Drug allergy definition   Allergic reactions are the hyper-immune response of our immune system to foreign (antigenic) substances. When certain foreign substances are introduced to the body, the immune system is triggered. (The immune system protects us from substances that may harm the body.) A hyper-immune response may result in allergic reaction symptoms. Medications are foreign substances and some of their components may trigger the immune systems of some people. What are the signs and symptoms of an allergy to drug (medication) allergy?  Readers Comments 3  Share Your Story Drug allergic reactions are similar to allergic reactions resulting from food and other substances that we ingest. A person's genetic make-up helps determine what they are allergic to, and the severity of their allergies. Allergic reactions, including drug allergy reactions, can be mild, moderate or even deadly. Mild drug allergy reactions include: Itching Rash Hives More serious reactions involve swelling of lips, tongue that can cause difficulty breathing (anaphylaxis) that can lead to death. Other signs and symptoms of drug allergies include: Dizziness Diarrhea Nausea Vomiting Abdominal cramps Seizure Low blood pressure Fainting Drug allergies may occur at any time during drug treatment. This means that the allergic reaction may occur after the first exposure to the drug or when the drug is taken again in the future. Allergic reactions are different from common side effects of many drugs such as a headache or upset stomach. To what types of drugs are people most allergic?  Readers Comments 4  Share Your Story Any drug or a component in a drug can cause an allergic reaction. Drugs that most commonly cause allergic reactions include: Penicillin and related drugs Sulfa drugs Insulin Iodine Other drugs that may cause an allergic reaction include: Chemotherapy drugs Drugs that suppress the immune system such as rituximab (Rituxan) and abatacept (Orencia) HIV medications Sometimes the allergic symptoms are caused by a component or substances used for packaging or administering the drug that triggers the allergy. Components of drugs that commonly cause allergies include: Dyes Egg proteins Peanuts Latex (in the packaging of drugs) Is there a test for drug (medication) allergies? Most times drug allergies are identified based on the time proximity of the reaction to administration of the drug and patient history. If the drug is stopped and the symptoms also stop; then the logical conclusion is that the drug caused the allergic reaction. Skin testing can also be used to verify that the drug is causing the allergy. If it is a drug that the patient needs and there are no other alternatives, careful skin testing can be done to determine if the person is truly allergic to the drug. What is the treatment for a drug (medication) allergy?   The first step is to stop the drug you suspect is causing the signs and symptoms. For skin reactions such as rashes and itching antihistamine creams (for exampleBenadryl) or steroid creams (for example, hydrocortisone) are used. Oral antihistamines and steroids are used for more bothersome symptoms. Antihistamines injections and or steroids are given for serious allergic reactions. For life threatening anaphylactic reactions which involve difficulty breathing, epinephrine is given usually intramuscularly. In situations where a drug is needed and there are no alternatives an allergist can attempt to desensitize the individual by gradually giving very small amounts of the drug and increasing the amount over a time. What should I do if I have an allergic reaction to a drug?  Readers Comments 2  Share Your Story Contact your doctor if you develop a rash, itching, hives or any symptom related to drug allergy. If your lip or tongue swells or if you have shortness of breath go the emergency room immediately. Do not drive yourself, call 911. Q