Tag Archives: Hay fever

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

Farm Pregnancy ‘Cuts Asthma Risk’

A picture of my wifeImage via Wikipedia

Living on a farm during pregnancy may help reduce the chance of the child developing asthma, eczema and even hayfever, say scientists.

..
Living on a farm while pregnant may benefit the baby

The New Zealand researchers suggest that exposure to animals and the bacteria they carry may affect the foetus’s immune system.

Writing in the European Respiratory Journal, they said exposure before and after birth halved the risk.

But experts warn some animals carry infections which may harm the baby.

The research, carried out at Massey University, adds to other studies which have suggested that living on a farm, with regular contact with animals, during the early years of life, could cut the risk of asthma and other allergic diseases.

But the study of more than 1,300 farmers’ children goes further, suggesting that this protection could start building even before birth.

It found that the greatest apparent protection – a 50% reduction in asthma, and an even greater reduction in eczema and hay fever – was gained by children whose mothers had been exposed to farm life during pregnancy, and who currently lived on a farm.

The reasons why this might happen are unclear, although they are likely to be related to the way that the child begins to develop its immune system.

Milk bacteria

Living on a farm means frequent contact with animal bacteria, perhaps through the consumption of unpasteurised milk, or contact with the animals directly.

The researchers suggested that this might suppress the production of particular immune cells linked to the development of asthma.

However, they suggested that while exposure during pregnancy might be useful, it might only persist if the child was exposed after its birth as well.

The findings are unlikely to lead to any change in current advice to pregnant women, which urges caution about contact with certain farm animals.

In particular, an infection which can cause miscarriage in pregnant ewes can lead to the same result in humans.

The faeces of other animals can also carry infections which can affect a pregnancy.

Dr Elaine Vickers, research manager at Asthma UK, said: “This study adds to existing evidence supporting the hygiene hypothesis, which states that early exposure to potential allergens results in a reduced risk of asthma development.

“However, the causes of asthma are still largely unknown and the processes involved in asthma development are incredibly complicated, including family history, environment and lifestyle.”

Sources: BBC NEWS:30Th. Aug.’08

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Hay Fever: Beat the Sneeze

Hay fever sufferers face a really bad summer. Lucy Atkins offers advice.

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This summer’s pollen forecast is one of the worst ever, meaning that about one in four of us can expect to slip into a wheezing fug any minute.

Experts say that we are surprisingly inept at managing our symptoms. Many of us do not understand our hay fever triggers and take inappropriate medications. Others throw away money on alternative “remedies” that do not work.

Simply popping a pill when symptoms get out of hand is not the best approach.

“People don’t realise you have to take the right dose at the right time in order to keep levels of the drug high in your system,” says Maureen Jenkins, allergy nurse and spokeswoman for Allergy UK.

“Otherwise it just won’t work.”

Antihistamine nasal sprays can stop your nose running, nasal steroid sprays can unbung you and sprays containing a drug called sodium cromoglicate, a “mast cell stabiliser”, can stop white blood cells from releasing histamine, which causes the sneezing and itching.

But Jenkins says that “many people have no idea how to use these sprays properly.” It is no good just stuffing the product up your nose – a good spraying technique is vital (see below). It is also important to follow dosage instructions.

The sodium cromoglicate spray, for instance, will only work if you start to use it two weeks before your allergy begins, then keep using it four times a day. Many other medications work best if you start to use them before your allergies kick in, allowing the drug to build up in your system. To do this you have to know your triggers.

Though there are many pollen allergens, birch and grass are the most common. These two are usually released in different months, but experts say that this summer, perhaps because of climate change, they are likely to overlap. According to the Royal Pharmaceutical Society, more than 5million of us could be taking inappropriate medicines because we have misdiagnosed our allergies.

Talking to your pharmacist before buying medicines is the first step to a sniffle-free summer. In addition, Allergy UK has just started an “accredited pharmacy allergy screening service” in association with the National Pharmacy Association. At these centres Allergy UK-trained pharmacists can diagnose triggers then recommend the right over-the-counter medications for your specific allergy type.

They can also refer you to a GP with details of the nearest appropriate allergy specialist. GPs are a good source of help if you are a severe sufferer. Several effective antihistamines can be obtained only on prescription and some people may be suitable for a newly developed kind of immunotherapy, where you either dissolve tablets under the tongue or have regular injections.

Those who want to avoid medication may turn to anything from fish oils to Reishi mushrooms as miracle hay fever cures. But there is no clinical evidence that nutritional supplements or dietary changes work on hay fever symptoms (although the herb butterbur has shown promise in clinical trials).

Acupuncture has had mixed success in trials. Daniel Maxwell of the British Acupuncture Council, says: “It’s great for hay fever because of the significant effect it has on modulating the immune system.”

Homeopathic treatments have also shown some promising clinical results, though more trials are needed. In other words, although you can’t avoid this year’s pollen onslaught, you may be more empowered than you think to defend yourself against it.

Click for natural and home remedy for Hay Fever:->.…………………...(1)…….(2).…….(3)………(4)

Sources:Telegraph.co.uk

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Anaphylaxis (Severe Allergic Reactions)

Alternative Names:
Anaphylactic reaction; Anaphylactic shock; Shock – anaphylactic

Anaphylaxis is a severe, sometimes life-threatening, allergic reaction that occurs within minutes of exposure an allergy-causing substance (allergen). Anaphylaxis also is called anaphylactic shock.

In a severe allergic reaction, the body’s immune system responds to the presence of an allergen by releasing histamine and other body chemicals. These chemicals cause the symptoms of allergies, which are usually mild but annoying, such as the runny nose of hay fever (allergic rhinitis) or the itchy rash of poison ivy. However, in some cases, the symptoms can be much worse and involve the entire body. Anaphylaxis is the most severe allergic reaction. In anaphylaxis, these immune chemicals cause serious skin symptoms, such as hives and swelling, as well as severe breathing problems, such as swelling in the throat, narrowing of the lower airways and wheezing). The chemicals also cause blood vessels to widen dramatically, which leads to a rapid, severe drop in blood pressure (shock). Anaphylaxis is a life-threatening medical emergency.

Although the specific allergen that triggers anaphylaxis may be different for each patient, it often can be traced to one of the following sources:

Foods — Especially eggs, seafood, nuts, grains, milk and peanuts
Drugs — Especially an antibiotic from the penicillin or cephalosporin group
Insect stings — From bees, yellow jackets, paper wasps, hornets or fire ants
Injected anesthetics — Procaine, lidocaine
Dyes — Used in diagnostic X-rays and scans
Industrial chemicals — Latex and rubber products used by health care workers
Allergy shots (immunotherapy)
Symptoms
Symptoms of anaphylaxis usually occur within seconds to minutes of exposure to the allergen and range from mild to very severe. These symptoms include:

Rapid pulse, sweating, dizziness, fainting, unconsciousness
Wheezing, chest tightness, difficulty breathing, coughing
Itchy hives, which may blend together to form larger areas of skin swelling
Swelling of the lips, tongue or eyes
Nausea, vomiting, abdominal cramps, diarrhea
Paleness, bluish skin color
Throat swelling, with a feeling of throat tightness, a lump in the throat, hoarseness or obstructed air flow.
Difficulty breathing
Wheezing
Abnormal (high-pitched) breathing sounds
Confusion
Slurred speech
Rapid or weak pulse
Blueness of the skin (cyanosis), including the lips or nail beds
Fainting, light-headedness, dizziness
Hives and generalized itching
Anxiety
Sensation of feeling the heart beat (palpitations)
Nausea, vomiting
Diarrhea
Abdominal pain or cramping
Skin redness
Nasal congestion
Cough
Diagnosis
The doctor will ask about the patient’s allergy history and about his or her exposure to any of the common allergens that trigger anaphylaxis. It is very important for the doctor to know if the patient’s symptoms started soon after exposure to an allergen, for instance after eating nuts, after a bee sting or after taking an antibiotic. Because the patient may be too sick to provide this information, a family member, friend, co-worker or school nurse will need to help. People with a history of severe allergic reactions should consider wearing a medical alert identification necklace or bracelet to save valuable time in identifying the problem.

The doctor usually can diagnose anaphylaxis based on the patient’s history and the results of a physical examination.

Expected Duration
With early and appropriate treatment, cases of anaphylaxis can improve quickly within a few hours. If a person has already developed the more serious symptoms and dangerous conditions, it may take a few days to recover after treatment. If untreated, anaphylaxis can cause death within minutes to hours.

Prevention
You can prevent anaphylaxis by avoiding the allergens that trigger your symptoms. For example, people with food allergies should always check the list of ingredients on food labels, and they should always ask the waiter about food ingredients before eating at a restaurant. If you are allergic to bee stings, you should limit gardening and lawn mowing, and you should not wear perfumes, hair sprays or bright clothing that attracts insects.

People with a history of anaphylaxis should wear a medical identification bracelet or necklace to alert others in the event of another reaction. In addition, ask your doctor if you should carry a pre-loaded syringe of epinephrine (adrenaline), a medicine used to treat anaphylaxis. At the first sign of symptoms, you or a competent helper (family member, co-worker, school nurse) would inject the pre-loaded epinephrine to treat your allergic reaction until you reach medical attention.

Allergy shots, also called immunotherapy, are used to gradually desensitize patients to insect allergies. On rare occasions, allergy shots also can be used to prevent certain medication allergies. However, they cannot prevent food allergies.
Signs and tests
Examination of the skin may show hives and swelling of the eyes or face. The skin may be blue from lack of oxygen or may be pale from shock. Angioedema in the throat may be severe enough to block the airway.

Listening to the lungs with a stethoscope may reveal wheezing or indicate fluid (pulmonary edema). The pulse is rapid, and blood pressure may be low. Weakness, pale skin, heart arrhythmias, mental confusion, and other signs may indicate shock.

Testing for the specific allergen that caused anaphylaxis (if the cause is not obvious) is postponed until after treatment.
Treatment
Some early cases of anaphylaxis can be treated with antihistamines and corticosteroids. More severe cases can be life-threatening emergencies and require immediate medical attention. If available, epinephrine should be given at the first sign of a serious reaction to slow the progression of symptoms. Doctors treat anaphylaxis with the medication epinephrine and with intravenous fluids. The person also may need additional treatment with oxygen, mechanical ventilation (a machine helps the patient breathe temporarily), and additional medications such as antihistamines or corticosteroids given intravenously (into a vein).

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Complications
Shock
Cardiac arrest (no effective heartbeat)
Respiratory arrest (absence of breathing)
Airway obstruction

When To Call A Professional
Call for emergency assistance immediately whenever anyone has symptoms of anaphylaxis. If you have a history of severe allergic reaction and have not mentioned this to your doctor, schedule an appointment as soon as possible. He or she can review your history and help you take the necessary precautions to avoid future problems.

Prognosis
With prompt, appropriate treatment, most patients who have had a severe allergic reaction can recover completely. Unfortunately, even with treatment, some people die from anaphylaxis.

A person who has had anaphylaxis is at risk of future severe reactions if he or she is exposed again to the same allergen.

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.
Help taken from:www.intelihealth.com and www.healthline.com

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