Categories
Ailmemts & Remedies

Food Allergy

Definition:
Food allergy is an immune system reaction that occurs soon after eating a certain food. Even a tiny amount of the allergy-causing food can trigger signs and symptoms such as digestive problems, hives or swollen airways. In some people, a food allergy can cause severe symptoms or even a life-threatening reaction known as anaphylaxis

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Food allergy affects an estimated 6 to 8 percent of children under age 3, and about 4 percent of adults. While there’s no cure, some children outgrow their food allergy as they get older. It’s easy to confuse a food allergy with a much more common reaction known as food intolerance. While bothersome, food intolerance is a less serious condition that does not involve the immune system.

Food allergy is distinct from other adverse responses to food, such as food intolerance, pharmacologic reactions, and toxin-mediated reactions.

Food allergy :Adverse immune response to a food protein

Pharmacologic: Caffeine tremors, cheese/wine (tyramine) migraine, scombroid (histamine) fish poisoning

Toxins:Bacterial food poisoning, staphylotoxin

Intolerance: lactose intolerance (lactase deficiency)

The food protein triggering the allergic response is termed a food allergen. It is estimated that up to 12 million Americans have food allergies, and the prevalence is rising. Six to eight percent of children under the age of three have food allergies and nearly four percent of adults have them. Food allergies cause roughly 30,000 emergency room visits and 100 to 200 deaths per year in the United States. The most common food allergies in adults are shellfish, peanuts, tree nuts, fish, and eggs, and the most common food allergies in children are milk, eggs, peanuts, and tree nuts.

Treatment consists of avoidance diets, in which the allergic person avoids all forms of the food to which they are allergic. For people who are extremely sensitive, this may involve the total avoidance of any exposure with the allergen, including touching or inhaling the problematic food as well as touching any surfaces that may have come into contact with it. Areas of research include anti-IgE antibody (omalizumab, or Xolair) and specific oral tolerance induction (SOTI), which have shown some promise for treatment of certain food allergies. People diagnosed with a food allergy may carry an autoinjector of epinephrine such as an EpiPen or Twinject, wear some form of medical alert jewelry, or develop an emergency action plan, in accordance with their doctor.

Signs and symptoms:
Classic immunoglobulin-E (IgE)-mediated food allergies are classified as type-I immediate hypersensitivity reactions. These allergic reactions have an acute onset (from seconds to one hour) and may include:

*Angioedema: soft tissue swelling, usually involving the eyelids, face, lips, and tongue. Angioedema may result in severe swelling of the tongue as well as the larynx (voice box) and trachea, resulting in upper airway obstruction and difficulty breathing.

*Hives

*Itching of the mouth, throat, eyes, skin

*Nausea, vomiting, diarrhea, stomach cramps, and/or abdominal pain. This group of symptoms is termed gastrointestinal hypersensitivity or anaphylaxis.

*Rhinorrhea, nasal congestion

*Wheezing, scratchy throat, shortness of breath, or difficulty swallowing

*Anaphylaxis: a severe, whole-body allergic reaction that can result in death (see below)

The reaction may progress to anaphylactic shock: A systemic reaction involving several different bodily systems including hypotension (low blood pressure),loss of consciousness, and possibly death. Allergens most frequently associated with this type of reaction are peanuts, nuts, milk, egg, and seafood, though many food allergens have been reported as triggers for anaphylaxis.

Food allergy is thought to develop more easily in patients with the atopic syndrome, a very common combination of diseases: allergic rhinitis and conjunctivitis, eczema and asthma.[8] The syndrome has a strong inherited component; a family history of allergic diseases can be indicative of the atopic syndrome.

Conditions caused by food allergies are classified into 3 groups according to the mechanism of the allergic response:

1. IgE-mediated (classic):

Type-I immediate hypersensitivity reaction (symptoms described above)
Oral allergy syndrome
2. IgE and/or non-IgE-mediated:

*Allergic eosinophilic esophagitis
*Allergic eosinophilic gastritis
*Allergic eosinophilic gastroenteritis

3. Non-IgE mediated:

*Food protein-induced Enterocolitis syndrome (FPIES)

*Food protein proctocolitis/proctitis

*Food protein-induced enteropathy. An important example is Coeliac disease, which is an adverse immune response to the protein gluten.

*Milk-soy protein intolerance (MSPI) is a non-medical term used to describe a non-IgE mediated allergic response to milk and/or soy protein during infancy and early childhood. Symptoms of MSPI are usually attributable to food protein proctocolitis or FPIES.

*Heiner syndrome – lung disease due to formation of milk protein/IgG antibody immune complexes (milk precipitins) in the blood stream after it is absorbed from the GI tract. The lung disease commonly causes bleeding into the lungs and results in pulmonary hemosiderosis.

Pathophysiology:-
For more details on this topic, see allergy.
Generally, introduction of allergens through the digestive tract is thought to induce immune tolerance. In individuals who are predisposed to developing allergies (atopic syndrome), the immune system produces IgE antibodies against protein epitopes on non-pathogenic substances, including dietary components.[citation needed] The IgE molecules are coated onto mast cells, which inhabit the mucosal lining of the digestive tract.

Upon ingesting an allergen, the IgE reacts with its protein epitopes and release (degranulate) a number of chemicals (including histamine), which lead to oedema of the intestinal wall, loss of fluid and altered motility. The product is diarrhea.

Any food allergy has the potential to cause a fatal reaction
.

Causes:-
The immune system’s Eosinophils, once activated in a histamine reaction, will register any foreign proteins they see. One theory regarding the causes of food allergies focuses on proteins presented in the blood along with vaccines, which are designed to provoke an immune response. Influenza vaccines and the Yellow Fever vaccine are still egg-based, but the Measles-Mumps-Rubella vaccine stopped using eggs in 1994. However large scientific studies do not support this theory, especially as it applies to autoimmune disease.

Another theory focuses on whether an infant’s immune system is ready for complex proteins in a new food when it is first introduced.

One hypothesis at this time is the Hygiene hypothesis. While there is no proof for the hygiene hypothesis, people speculate that in modern, industrialized nations, such as the United States, food allergies are more common due to the lack of early exposure to dirt and germs, in part due to the over use of antibiotics and antibiotic cleansers. This hypothesis is based partly on studies showing less allergy in third world countries. Some research suggests[citation needed] that the body, with less dirt and germs to fight off, turns on itself and attacks food proteins as if they were foreign invaders.

Antibiotics have also been implicated in Leaky Gut Syndrome which is another possible cause of food allergies

A lower incidence of food allergies in the developing world could also be due to differences in diet from the West and less exposure to food allergens.

Others have found that food allergies are due to widespread usage of baby skin care products that contain allergens, such as lotions based upon peanut’s oil. These skin care products are cheaper to manufacture than non-allergenic ones and using them sensitizes the baby, which later develops into a food allergy. This theory has yet to come with sufficient explanation as to why occurrence of allergies are on a steady rise in the last two decades.

Prevention:-
According to a report issued by the American Academy of Pediatrics, “There is evidence that breastfeeding for at least 4 months, compared with feeding infants formula made with intact cow milk protein, prevents or delays the occurrence of atopic dermatitis, cow milk allergy, and wheezing in early childhood.”[23]

Treatment:-
The mainstay of treatment for food allergy is avoidance of the foods that have been identified as allergens.

If the food is accidentally ingested and a systemic reaction occurs, then epinephrine (best delivered with an autoinjector of epinephrine such as an Epipen or Twinject) should be used. It is possible that a second dose of epinephrine may be required for severe reactions. The patient should also seek medical care immediately.

At this time, there is no cure for food allergies. There are no allergy desensitization or allergy “shots” available for food allergies. Some doctors feel they do not work in food allergies because even minute amounts of the food in question or even food extracts (as in the case of allergy shots) can cause an allergic response in many sufferers.

Ronald van Ree of Amsterdam University expects that vaccines can in theory be created using genetic engineering to cure allergies. If this can be done, food allergies could be eradicated in about ten years.
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Statistics:-
For reasons that are not entirely understood, the diagnosis of food allergies has apparently become more common in Western nations in recent times. In the United States food allergy affects as many as 5% of infants less than three years of age and 3% to 4% of adults. There is a similar prevalence in Canada.

The most common food allergens include peanuts, milk, eggs, tree nuts, fish, shellfish, soy, and wheat – these foods account for about 90% of all allergic reactions.

Differing views:-
Various medical practitioners have a differing views on food allergies. Irritable Bowel Syndrome (IBS) patients have been studied with regards to food allergies. Some studies have reported on the role of food allergy in IBS; only one epidemiological study on functional dyspepsia and food allergy has been published. However, since 2005 several studies have demonstrated strong correlation between IgG and/or IgE food allergy and IBS symptoms The mechanisms by which food activates mucosal immune system are incompletely understood, but food specific IgE and IgG4 appeared to mediate the hypersensitivity reaction in a subgroup of IBS patients. Specific chemicals and receptors have been demonstrated to be critical in food allergy development in murine models. Exclusion diets based on skin prick test, RAST for IgE or IgG4, hypoallergic diet and clinical trials with oral disodium cromoglycate have been conducted, and some success has been reported in a subset of IBS patients.

Studies comparing skin prick testing and ELISA blood testing have found that the results of skin prick testing correlate poorly with symptoms of irritable bowel syndrome that correlate with food allergies demonstrated through ELISA testing and dietary challenge.

Extensive clinical experience has demonstrated significant improvement of patients with IBS whose ELISA-based food allergy testing is positive and where treatment includes a careful exclusion diet.

In addition, many practitioners of alternative medicine ascribe symptoms to food allergy where other doctors do not. The causal relationships between some of these conditions and food allergies have not been studied extensively enough to provide sufficient evidence to become authoritative. The interaction of histamine with the nervous system receptors has been demonstrated, but more study is needed.[36] Other immune response effects are commonly known (swelling, irritation, etc.), but their relationships to some conditions has not been extensively studied. Examples are arthritis, fatigue, headaches, and hyperactivity. Nevertheless, hypoallergenic diets reportedly can be of benefit in these conditions, indicating that the current medical views on food allergy may be too narrow. Holford and Brady (2005) suggest three levels of response; classical immediate-onset allergy (IgE), delayed-onset allergy (giving a positive response on an ELISA IgG test but rarely on an IgE skin prick test), and food intolerance (non-allergic), and claim the last two to be more common. It is important to note that IgG is present in the body and is known to respond to foods. So some medical practitioners, especially allergists, claim that there is no predictive value to these types of tests, despite the studies cited above.

In children:-
Milk and soy allergies in children can often go undiagnosed for many months, causing much worry for parents and health risks for infants and children. Many infants with milk and soy allergies can show signs of colic, blood in the stool, mucous in the stool, reflux, rashes and other harmful medical conditions. These conditions are often misdiagnosed as viruses or colic.

Some children who are allergic to cow’s milk protein also show a cross sensitivity to soy-based products.[ There are infant formulas in which the milk and soy proteins are degraded so when taken by an infant, their immune system does not recognize the allergen and they can safely consume the product. Hypoallergenic infant formulas can be based on hydrolyzed proteins, which are proteins partially predigested in a less antigenic form. Other formulas, based on free amino acids, are the least antigenic and provide complete nutrition support in severe forms of milk allergy.

Seventy-fice percent of children who have allergies to milk protein are able to tolerate baked-in milk products, ie., muffins, cookies, cake.

About 50% of children with allergies to milk, egg, soy, and wheat will outgrow their allergy by the age of 6. Those that don’t, and those that are still allergic by the age of 12 or so, have less than an 8% chance of outgrowing the allergy.

Peanut and tree nut allergies are less likely to be outgrown, although evidence now shows[40] that about 20% of those with peanut allergies and 9% of those with tree nut allergies will outgrow their allergies. In such a case, they need to consume nuts in some regular fashion to maintain the non-allergic status.[citation needed] This should be discussed with a doctor.

Those with other food allergies may or may not outgrow their allergies.

Labeling laws
In response to the risk that certain foods pose to those with food allergies, countries have responded by instituting labeling laws that require food products to clearly inform consumers if their products contain major allergens or by-products of major allergens.

United States law
Under the Food Allergen Labeling and Consumer Protection Act of 2004 (Public Law 108-282), companies are required to disclose on the label whether the product contains a major food allergen in clear, plain language. The allergens have to clearly be called out in the ingredient statement. Most companies list allergens in a statement separate from the ingredient statement

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IT IS ADVISED TO DO  YOGA & MEDITATION  (BREATHING EXERCISE) DAILY  TO GET RID OF ALLERGY 

Disclaimer: This information is not meant to be a substitute for professional medical advise or help. It is always best to consult with a Physician about serious health concerns. This information is in no way intended to diagnose or prescribe remedies.This is purely for educational purpose.

Resources:

http://en.wikipedia.org/wiki/Food_allergy
http://www.mayoclinic.com/health/food-allergy/DS00082/DSECTION=symptoms

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Categories
Ailmemts & Remedies

Insect Allergy

Definition:
Insect  allergy from its venom is a harmful reaction to insect stings that occurs in people who have an abnormally high sensitivity to insect venom. It is an acquired trait, which is not present at the first exposure to the venom, but sensitization can occur after the first or subsequent exposures. Animals classified as insects usually have three main body segments (head, thorax and abdomen), six legs and a pair of sensory antennae. Winged insect species have two sets of wings, such as mosquitoes, bees, and wasps. Other biting or stinging insects include fleas, lice, and ants. Many other related animals that are frequently mistaken for insects such as ticks, spiders and mites also bite human beings. They can transmit infectious diseases or cause poisoning but generally do not cause allergic reactions. Allergic reactions to the venom of some stinging insects, such as honey bee, yellow jacket, hornet, wasp or fire ant can be life threatening.

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Who gets it?
While not everyone is allergic to insect venom, reactions in the skin such as mild pain, swelling, and redness may occur with an insect sting. Anyone can experience an allergic reaction to an insect bite or sting. However, only a small number of people with insect bite or sting allergies suffer fatal reactions.

Who is at risk for insect sting allergies?
Over 2 million Americans are allergic to stinging insects. The degree of allergy varies widely. Most people are not allergic to insect stings, and most insect stings result in only local itching and swelling. Many, however, will have severe allergic reactions. Severe allergic reactions to insect stings are responsible for at least 50 deaths each year in the U.S.

If you are known to be allergic to insect stings, then the next sting is 60% likely to be similar or worse than the previous sting. Since most stings occur in the summer and fall, you are at greatest risk during these months. Males under the age of 20 are the most common victims of serious insect-sting allergic reactions, but this may reflect a greater exposure to insects of males, rather than a true predisposition.

Causes:
An allergic reaction occurs when the immune system produces antibodies and other disease fighting cells in response to an allergen, in this case the insect venom. The antibodies release chemicals that actually injure the surrounding cells and cause the physical symptoms of an allergic reaction. Certain antibodies release histamines, which affect the skin, mucous membrane, mucous gland, and smooth muscle cells. Life-threatening allergic reactions can occur without any previous symptoms of allergy. In fact, most people with insect bite or sting allergies do not experience a severe reaction with their first bite. Multiple bites or stings increase the risk of an allergic reaction, but just one bite will cause serious symptoms for someone who is severely allergic.

What insects are usually involved?
Most serious allergic reactions to insect venom are caused by stinging insects, such as bees, yellow jackets, hornets, wasps and imported fire ants. As natives of the tropics, fire ants can live only in the warmer climate of the southern states and cannot survive in the north. They are extremely aggressive and sting exposed parts of the skin when they feel threatened. Bites or stings from other insects usually do not cause allergic reaction.

Symptoms:
Symptoms of insect venom allergy often begin within 15 to 30 minutes and arise distant from the site of sting. The first symptom is often itchiness that can affect all or any part of the skin, the eyes and the nose. As symptoms progress, the patient begins to sneeze, cough and wheeze, feel congested, and develop hives or swelling. These symptoms may be warning signs of a dangerous condition called anaphylaxis. Symptoms of anaphylaxis include sudden anxiety and weakness, difficulty breathing, tightness in the chest, lightheadedness and palpitation, and loss of consciousness. Anaphylactic shock can occur within minutes and result in death. Anaphylaxis is a medical emergency that needs immediate medical treatment, and any delay may reduce the chance of survival.

Diagnosis:

Insect venom allergy is suspected based on a constellation of suggestive symptoms that follow an insect sting. The diagnosis is confirmed by performing a skin test with the venom of specific insects, such as honey bee, yellow jacket, hornet, wasp or fire ant that may be the culprit of the allergic reaction.

Treatment:
If you have been bitten or stung by an insect, carefully remove the stinger, if it is left behind. Wash the bite/sting area gently with soap and water. Apply ice to the site of sting. People who are allergic to insect bites should, of course, avoid situations in which they are likely to get stung or bitten. Mild reactions, such as pain, itching, and swelling, can be treated with an over-the counter antihistamine, pain reliever and topical corticosteroid creams. Anaphylactic shock is treated with an injection of epinephrine, a hormone that stimulates the heart and relaxes the airways. This may be combined with an injection of an antihistamine, which counteracts the histamine produced by the immune cells during an allergic reaction. Those who are known to have severe insect venom allergies should carry a self-injection kit, including antihistamine tablets, for emergency treatment. However, they should still seek emergency medical care after any type of reaction to an insect bite or sting.

People who are severely allergic to the venom of stinging insects, such as bees, yellow jackets, hornets, wasps or fire ants may, undergo a desensitization. First, skin testing is performed by an allergy specialist to determine the type of insect that responsible for the venom allergy. Then the patient receives a series of injections of the venom from the same insect(s). Starting dose is minute but increasingly larger doses are given until the venom doses several times larger than a single insect sting can be tolerated. This type of program must be administered by an allergy specialist, and it usually takes 20 weekly injections to eliminate this abnormal and exaggerated sensitivity. These are followed up with monthly booster shots and continued for 3 to 5 years to consolidate the cure.
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Self-care tips
There are many ways you can help prevent insect bites and stings. Don’t use flowery colognes, soaps, or lotions, or wear brightly colored clothing, which attract insects. Do not keep open garbage or food that attract stinging insects when you are outdoors. Avoid drinking sweet beverages especially from open cans that have been left unattended and may harbor insects. Wear light, protective clothing such as long sleeves top and long pants whenever you will be outside for longer periods of time. Wear work gloves when you are gardening. Do not walk barefoot on the grass where insects are difficult to detect and can be stepped on. If an insect is near you, move away. Do not swat at the insect, which may awaken its defensive instincts and trigger aggressive behavior. Make sure any insect nests around your home are removed and destroyed.

Stinging Insect Allergies At A Glance:-
*Severity of reactions to stings varies greatly.

*Most insect stings do not produce allergic reactions.

*Anaphylactic reactions are the most serious reactions and can be fatal.

*Avoidance and prompt treatment are essential.

*Epinephrine (available in portable, self-injectable form) is the treatment of choice for anaphylactic reactions.

*In selected people, allergy injection therapy is highly effective in preventing future reactions.

*The three “A’s” of insect allergy are adrenaline, avoidance, and allergist.


The U.S. Department of Agriculture recommends the following:

*Avoid disturbing likely beehive sites, such as large trees, tree stumps, logs, and large rocks.

*If a colony is disturbed, run and find cover as soon as possible. Running in a zigzag pattern may be helpful.

*Never stand still or crawl into a hole or other space with no way out.

*Do not slap at the bees.

*Cover as much of the head and face as possible, without obscuring vision, while running.

*Once clear of the bees, remove stingers and seek medical care if necessary, especially if there is a history of allergy to bee venom.

For more knowledge you may click to see:->Insect Allergy Reminders

Disclaimer: This information is not meant to be a substitute for professional medical advise or help. It is always best to consult with a Physician about serious health concerns. This information is in no way intended to diagnose or prescribe remedies.This is purely for educational purpose.

Resources:
http://www.hmc.psu.edu/healthinfo/i/insectallergy.htm
http://www.medicinenet.com/insect_sting_allergies/article.htm

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Categories
Diagnonistic Test

Scratch Test for Allergies

allergy test 7/22/05
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Definition:
For more than a century, doctors have used skin tests to help diagnose allergies. During these tests, your skin is exposed to allergy-causing substances (allergens) and then is observed for signs of an allergic reaction.

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Along with your medical history, skin tests can confirm whether signs and symptoms, such as sneezing, wheezing and skin rashes, are caused by allergies. They can also identify the specific substances that trigger allergic reactions. Such information can help your doctor develop an allergy treatment plan that may include allergen avoidance, medications or allergy shots (immunotherapy).

This test checks for a skin reaction to common allergy-provoking substances, such as foods, molds, dust, plants, or animal proteins. If your skin reacts to a substance, chances are that you are allergic to it.

Most people with allergy symptoms don’t need testing because they can identify their triggers and control their symptoms with medicine. Your doctor might recommend scratch testing when you have severe allergy symptoms but are not sure what is causing them. Knowing what you are allergic to can help you avoid the substance in the future, and will help your doctor determine whether you might benefit from allergy shots.

Why it’s actually done?
Skin testing is widely used to diagnose allergic conditions such as hay fever, allergic asthma and dermatitis (eczema). It’s safe for people of all ages, including infants and older adults.

Sometimes, however, skin tests aren’t recommended. Your doctor may advise against skin testing if you:

*Take medications that interfere with test results. These include antihistamines, many antidepressants and some heartburn medications. Your doctor may determine that it’s better for you to continue taking these medications than to temporarily discontinue them in preparation for a test.

*Have a severe skin disease. If conditions such as eczema or psoriasis affect large areas of skin on your arms and back — the usual testing sites — there may not be enough clear, uninvolved skin to conduct an effective test.

*Are highly sensitive to suspected allergens. You may be so sensitive to certain substances that even the small amounts of them used in skin tests could trigger a severe allergic reaction (anaphylaxis).

Blood tests (technically called in vitro allergen-specific IgE antibody tests) are particularly useful for those who should not undergo skin tests. Although blood tests can be as accurate as skin tests, they’re not performed as often because they may be less sensitive and are more expensive. If you want to start immunotherapy — a series of injections intended to increase your tolerance to allergens — you need either a skin or blood test to identify the specific substances that trigger your allergies.
.What risks are there from the test?
Because the allergen exposure is so small, a serious allergic reaction is extremely unlikely.

The most common side effect of skin testing is itching and redness. This may be most noticeable during the test, when you aren’t allowed to scratch yourself.For a few hours you’ll probably have some redness or irritation on the testing sites, similar to having several mosquito bites. It usually subsides within a few hours, although it can persist until the next day. A mild cortisone cream can be applied to relieve the itching and redness.

Rarely, skin tests can produce a severe, immediate allergic reaction, so it’s important to have skin tests performed at an office where appropriate emergency equipment and medications are available. If you develop a severe allergic reaction in the days after a skin test, call your doctor right away.

Some doctors who practice complementary or alternative medicine may perform provocation-neutralization tests, but these tests aren’t proved and aren’t considered reliable.
.How you prepare for the test ?
Before recommending a skin test, your doctor will ask detailed questions about your medical history, your signs and symptoms, and your usual way of treating them. Your answers can help your doctor determine if allergies run in your family and if you might also have them.

Next, your doctor will perform a physical examination to search for additional clues about the causes of your signs and symptoms.

Your medical history and physical examination may provide enough information for your doctor to discuss your diagnosis and treatment. If so, a skin test may be unnecessary. But if your doctor is uncertain or suspects that you have allergies and needs more information about the possible causes, he or she may recommend that you have a skin test.

Before scheduling a skin test, your doctor will need a list of all your prescription and over-the-counter medications. Some medications can suppress allergic reactions preventing the skin testing from working effectively. Other medications may increase your risk of developing a severe allergic reaction during a test.

Because medications clear out of your system at different rates, your doctor may ask that you stop taking certain medications for up to 10 days. Medications that can interfere with skin tests include:

*Prescription nonsedating antihistamines, such as fexofenadine (Allegra) and cetirizine (Zyrtec)

*Over-the-counter antihistamines (Claritin, Benadryl, Chlor-Trimeton, others)

*Tricyclic antidepressants, such as amitriptyline and doxepin (Sinequan)

*Heartburn medications, such as cimetidine (Tagamet) and ranitidine (Zantac)

Tell your doctor if you have ever had anaphylaxis, a lifethreatening allergic reaction, or if you have had a serious reaction to a previous allergy test.

What happens when the test is performed?

In adults, the test is done on the forearm; in children it’s done on the upper back. (The child disrobes from the waist up and lies on his or her stomach.)

Your doctor decides what allergies are to be tested for. Some people are tested for as many as a few dozen at one visit. Individual drops of fluid are dripped in rows across the skin. The doctor uses a needle to make small light scratches in the skin under each drop, to help the skin absorb the fluid. The scratches aren’t deep enough to cause bleeding. Each drop contains proteins from a separate allergen (a substance, like ragweed pollen, that triggers allergy symptoms).Your doctor notes where each drop of fluid was placed, either by keeping a chart or by writing a code on the area of skin being tested.

For many people, the most difficult part of this test is next: You need to stay still long enough (usually about 20 minutes) to give the skin time to react. Your skin might tickle or itch during this time, but you won’t be allowed to scratch it. At the end of the waiting time, your doctor will examine each needle scratch for redness or swelling.

What must you do special after the test is over?
Nothing.

What you can expect from the test?
Contrary to what you may have heard, skin tests cause little if any discomfort. Because the needles used in these tests barely penetrate your skin’s surface, you won’t bleed or feel more than mild, momentary discomfort.

Some tests detect immediate allergic reactions, which develop within minutes of exposure to an allergen. Other tests detect delayed allergic reactions, which develop over a period of several days.

Procedure
Skin testing is usually performed in a doctor’s office. Typically, a nurse administers the test and a doctor interprets the results. The three main types of skin tests are:

*Puncture, prick or scratch test (percutaneous). In this test, which is the type of skin test most commonly performed, tiny drops of purified allergen extracts are pricked or scratched into your skin’s surface. This test is usually performed to identify allergies to pollen, mold, pet dander, dust mites, foods, insect venom and penicillin.

*Intradermal test (intracutaneous). Purified allergen extracts are injected into the skin of your arm. This test is usually performed if your doctor suspects that you’re allergic to insect venom or penicillin.

*Patch test (epicutaneous). An allergen is applied to a patch, which is then placed on your skin. This test is usually performed to identify substances that cause contact dermatitis. These include latex, medications, fragrances, preservatives, hair dyes, metals and resins.

Tests for immediate allergic reactions:
A puncture, prick or scratch test checks for immediate allergic reactions to as many as 40 different substances at one time. In adults, the test is usually done on the forearm. Children are usually tested on the upper back.

After cleaning the test site with alcohol, the nurse draws small marks on your skin and applies a drop of allergen extract next to each mark. He or she then uses a sharp instrument (lancet) to introduce the extracts into the skin’s surface. A new lancet is used for each scratch to prevent cross-contamination of allergens. The drops are left on your skin for 15 minutes, and then the nurse observes your skin for signs of allergic reactions.

To see if your skin is reacting the way it’s supposed to, the nurse introduces two additional substances into your skin’s surface:

*Histamine. In almost everyone, this substance causes a skin response, so it’s used as a positive control. If you don’t react to histamine, the skin test may be difficult or impossible to interpret.

*Glycerin or saline. In almost everyone, these substances cause no reaction. So one or the other is used as a negative control. If you react to glycerin or saline, you may have sensitive skin, so your reactions to the allergen extracts will need to be interpreted with caution.

You may need a more sensitive immediate-reaction test — known as an intradermal test — if a puncture, prick or scratch test is inconclusive. During this test, a nurse uses a thin needle and syringe to inject a small amount of allergen extract just below the surface of the skin on your arm. Then he or she inspects the site after 15 minutes for a local skin reaction.

Tests for delayed allergic reactions
Patch tests detect delayed allergic reactions. During a patch test, your skin may be exposed to 20 to 30 extracts of substances that can cause contact dermatitis. Caustic substances — such as industrial solvents — are diluted to prevent skin damage.

Allergen extracts are applied to bandages that you wear on your arm or back for 48 hours. During this time, you should avoid bathing and activities that cause heavy sweating. The bandages are removed when you return to your doctor’s office for an evaluation.

Results:
Before you leave the doctor’s office, you’ll know the results of a puncture, prick or scratch test or an intradermal test. A patch test may take several days or more to produce results.

If an allergen provokes an allergic reaction to a puncture or intradermal skin test, you’ll develop a raised, red, itchy bump (wheal and flare) that may look like a mosquito bite. A nurse will then measure the bump’s size.

After the nurse records the results, he or she will clean your skin with alcohol to remove the marks and allergen droplets. Then you’ll meet with your doctor to discuss the results and possible treatment options.

A positive skin test means that you may be allergic to a particular substance. Bigger bumps usually indicate a greater degree of sensitivity. A negative skin test means that you probably aren’t allergic to that particular allergen.

The accuracy of skin tests can vary. You may react differently to the same test performed at different times. Or you may react positively to a substance during a test but not react to it in everyday life.

In general, skin tests are most reliable for diagnosing allergies to airborne substances, such as pollen, pet dander and dust mites. Because diagnosing food allergies can be complex, you may need additional tests or procedures.


Resources:

https://www.health.harvard.edu/diagnostic-tests/allergies-scratch-test.htm
http://www.mayoclinic.com/health/allergy-tests/MY00131/UPDATEAPP=false&FLUSHCACHE=0

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News on Health & Science

Study to Nail Food Allergy Triggers

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CHICAGO: For 5-year-old Sean Batson, even a grandmother’s kiss is to be feared.
“My mother was wearing lipstick, and when she kissed Sean’s cheek, it broke out in hives,” said his mother, Jennifer Batson.

At his first birthday party, Sean had a severe allergic reaction — hives, swollen eyes, vomiting and wheezing — to his first nibble of cake. And when a toddler with an ice cream cone touched Sean’s arm with sticky hands during a play date, the arm erupted in hives.

The daily struggle of living with Sean’s allergies to nearly unavoidable foods and food products — soy, eggs and milk, traces of which can turn up even in nonfoods like lipstick — prompted Jennifer and her husband, Tim, to participate in a project that scientists are calling the most comprehensive food allergy study to date.

The international study, led by Xiaobin Wang and Jacqueline Pongracic of Children’s Memorial Hospital here, is searching for causes of food allergy by looking at hundreds of families in Boston, Chicago and Anhui Province in China.

Wang says the study’s multicenter design allows researchers to look at startling variations in the prevalence and types of food allergies across diverse populations and regions.

In China, for example, skin-prick testing found that large percentages of one rural population were sensitive to shellfish (16.7%) and peanuts (12.3%). Yet actual food allergies in that population, as diagnosed by physicians, were all but unheard of: less than 1%.

In the US, by contrast, 12 million people (4%of the population) suffer from food allergies, according to the Food Allergy and Anaphylaxis Network, a nonprofit information and advocacy group.

“We found something unexpected,” said Wang, director of the Smith Child Health Research Program at Children’s Memorial. “The apparent dissociation between high allergic sensitization and low allergic disease in this Chinese population is not seen in our two US study populations.

Although it is possible to be allergic to any food, eight foods account for 90% of all reactions — milk, eggs, peanuts, fish, shellfish, soy, wheat, and tree nuts like cashews and almonds. Up to 200 deaths each year are attributed to the most severe reaction, food-induced anaphylaxis.

Some experts suggest that children in a culture smitten with antibacterial detergents and hand sanitizers are exposed to fewer germs, depriving the immune system of its germ-fighting job and leading it to misidentify certain foods as foreign.

Sources: The Times Of India

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Positive thinking

Clearing Our System

Food Allergies
In this day and age we know so much more about our relationship to food than our predecessors, and the way we eat and think about food has become almost unrecognizable to our grandparents’ generation. One example of this is our awareness of food allergies, a condition that has recently entered the collective consciousness. Most of us know someone who is allergic to such commonplace foods as wheat and dairy, and we may even be prone to such an allergy. Understanding how our bodies react to food, and making the necessary adjustments in our diet, can have a profound effect on our whole energy system, and can be the key to shifting our mind into a state of greater clarity.

When we are continuously exposed to a food that gives us an allergic reaction, we feel lethargic, foggy-headed, or as if we always have a low-grade sinus infection. Other symptoms can include nausea, digestive difficulties, skin problems, and difficulty breathing. Many of us have been fighting these symptoms our whole lives without realizing that getting relief could be as simple as cutting a particular food out of our diet. When we do, we feel as if we are waking up out of a fog, and our whole system, cleared of substances that work against it, benefits. Many people see skin improvements, they sleep better, have more energy, and feel able to think more clearly. When we feel less than well, testing ourselves, or getting tested by someone else, for food allergies may be a good place to start.

If you know how to do kinesiology, or if you work with a pendulum or have access to clear signals from an inner guide, you can test yourself. If these modes of gaining information are unfamiliar or uncomfortable, you can get tested through a doctor of your choice. However we go about it, exploring our relationship to the foods we eat can be the first step to a more optimal state of health, well-being, and clarity of mind.

Sources: Daily Om

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