Professeur docteur oussama chaalane

Dr Usama F Shaalan MD;PhD

Allergy

Step 1: What is an Allergy?
When most people think of an allergy, they think of the sneezing, congestion, and itchy eyes caused by pollen. In fact, allergies can be caused by just about any substance that you inhale or swallow, or which touches your skin.
Your body’s immune system is designed to attack harmful substances like bacteria and viruses. But with allergies, your body launches an assault on substances that are basically harmless — such as pollen, mold, dust mites, pet saliva and dander, and even medications and insect sting venom.
Allergies are extremely common. About 40% of the population suffers from them, leading to millions of missed work days and school days each year. Annual medical costs exceed $4 billion.
Not only do allergies cause a range of annoying symptoms such as sneezing and itchy eyes, but they can aggravate or trigger other conditions such as asthma, sinusitis, and ear infections. For example, when allergies cause inflammation in your nasal passages, the opening to your sinuses can become blocked, leading to sinus inflammation, sinus infections, and sinus pain. Similarly, if allergies cause inflammation in your ear canal, the ears don’t drain properly, which can lead to ear infections.
But allergies don’t stop there. The body’s immune system is active from your head to your toes: allergies can cause different skin-related symptoms (such as hives, eczema, and rashes); some types of allergies can lead to gastrointestinal problems; and assorted allergy-related symptoms can pervade the body (such as fatigue, headaches, loss of smell, and sleep disturbances).
One of the most deadly kinds of allergic reaction is called "anaphylaxis," which occurs when the entire body has a swift, severe reaction to something such as peanuts or bee stings. The body literally goes into shock, leading to a sharp drop in blood pressure, respiratory arrest, and possible heart failure.
To continue to the next step of the allergy guide, click "next" below.
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only — they do not constitute endorsements of those other sites. Copyright 2004 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
Return to IndexStep 1: What is an Allergy?Step 2: What Substances Cause Allergies?Step 3: Allergy-Related ConditionsStep 4: Should You See an Allergist?Step 5: Allergy Testing and DiagnosisStep 6: Overview of Allergy TreatmentStep 7: You and Your Doctor Are a TeamKey Points
Return to IndexStep 1: What is an Allergy?Step 2: What Substances Cause Allergies?Step 3: Allergy-Related ConditionsStep 4: Should You See an Allergist?Step 5: Allergy Testing and DiagnosisStep 6: Overview of Allergy TreatmentStep 7: You and Your Doctor Are a TeamKey Points
Step 2: What Substances Cause Allergies?
Allergens are everywhere — in the air we breathe, in the food we eat, in the cosmetics we use, and in plants in our backyard. Here are the most common ones.
Airborne allergens
Airborne allergens are the hardest to avoid, particularly pollen. Inhaling an allergen is the most common way people are exposed. This explains why allergy to pollen (also referred to as "hay fever") affects approximately 35 million Americans. Read detailed infomation on the most common inhaled allergens:
• Pollen
• Mold
• Dust mites
• Animal dander
Food
Any food can cause an allergic reaction. However, the foods that most commonly cause food allergy include peanuts, wheat, tree nuts, fish, shellfish, eggs, milk, and soy. Symptoms of food allergy can include stomach cramps, nausea, vomiting, or diarrhea. Some foods, including peanuts, celery, and shellfish, can cause anaphylaxis, a life-threatening condition that requires immediate medical attention. Food allergy is often confused with food intolerance and other conditions, which are not immune system reactions, but may have similar gastrointestinal symptoms. Read more about food allergy.
Insect stings
Insect stings usually cause localized pain and swelling in all people. In people allergic to insect stings, however, they can also cause anaphylaxis. An allergic reaction to insect sting venom sometimes happens with stunning swiftness because the allergen is injected directly into the bloodstream. Read more about insect sting allergic reaction.
Latex
Latex and additives used in the processing of latex can cause an allergic reaction. This has become a growing problem, particularly in the healthcare community, due to the increased use of latex as barrier protection against HIV and other contagious diseases. For people allergic to latex, repeated exposure can lead to anaphylaxis. Read more about latex allergy.
Poison ivy, oak, and sumac
Poison ivy, oak, and sumac are found throughout the United States. These plants give off an oil called urushiol. Very small amounts of this oil can cause allergic contact dermatitis, an itchy and blistery rash. This is a classic example of an allergy that does not need antibodies to cause a reaction. Read more about poison plants.
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only — they do not constitute endorsements of those other sites. Copyright 2004 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
Allergy-Related Conditions
If you have allergies, you may find that they affect your body in different ways. Allergy-related conditions generally involve the head (eyes, nose, mouth, throat, and ears), the lungs, GI tract, and/or the skin, all of which are involved in the body’s frontline of defending itself from foreign substances. Different allergy-related conditions may occur together because they involve shared passageways in the upper respiratory tract. Also, people with allergies are more likely to have more than one of these conditions because of their hypersensitive immune system.
Allergic rhinitis
Allergic rhinitis, commonly referred to as "hay fever," affects 40 million people annually in the United States. The term "rhinitis" means inflammation of the lining of the nose. Common symptoms include stuffy and runny nose, itching, and sneezing. (There are other potential causes of these symptoms unrelated to allergies, like the common cold.) Allergic rhinitis can be seasonal or year-round, depending on what you are allergic to. Read more about allergic rhinitis.
Asthma
Asthma is a chronic lung disease where the airways narrow, resulting in coughing, wheezing, shortness of breath, or chest tightness. Pollen and other allergens can trigger asthma. Asthma causes the bronchial tubes and bronchioles (small branches of the lungs) to constrict, making it difficult to breathe. Read more about asthma.
Sinusitis
"Sinusitis" refers to inflammation of the nasal sinus cavities, which are hollow spaces in the bones of the skull located behind the nose and eyebrows. Sinusitis can be acute or chronic and is often caused by infection, allergic inflammation, nasal polyps, or bone structure abnormalities. Symptoms may include facial pain, headache, stuffy and runny nose, discolored mucus (yellow or green), cough, diminished sense of smell, bad breath, fever, or pressure in the ears. Read more about sinusitis.
Ear infections and otitis media
The term "otitis media" means inflammation of the
middle ear, often due to colds or allergies. The inflammation often leads to ear infections. Early signs are ear pain and discomfort. Children may have trouble sleeping, lose their appetite, or show signs of irritability. Otitis media occurs most often among infants and young children because their inner ears are less developed and at an angle where bacteria and other irritants can easily enter through the throat. Read more about otitis media.
Conjunctivitis
Conjunctivitis, commonly referred to as "pink eye," is an inflammation of the lining of the eye. Symptoms include red, itchy, and tearing eyes. Conjunctivitis can be caused by allergies or infection. Seasonal allergic conjunctivitis is common and usually occurs with allergic rhinitis. Like the nose, the eye is easily irritated by airborne allergens in the environment. Read more about conjunctivitis.
Dermatitis
Dermatitis is inflammation of the skin. There are several types of dermatitis that are allergy-related, including atopic dermatitis (also called "eczema") and contact dermatitis. Atopic dermatitis usually appears in the first few years of life as a recurring, intensely itchy rash. Contact dermatitis appears as an itchy, red, and blistery rash after contact with an allergen, like poison ivy.
Hives
Hives, also called urticaria, appear as red, itchy, raised welts on the skin. Acute urticaria is often an allergic reaction to food or drugs and often lasts only a few days. Acute urticaria affects 10-20% of people at least once in their life. Chronic urticaria can last longer than six months, and the cause is often unknown. Read more about hives.
Anaphylaxis
Anaphylaxis is a life-threatening condition that requires immediate emergency medical treatment. Anaphylaxis is an immediate immune system reaction during which histamine and other chemicals are released all over the body. If not treated right away, anaphylaxis may cause shock or death. The most common allergens that cause this type of reaction include insect sting venom, peanuts, and shellfish. Read more about anaphylaxis.
Early signs of anaphylaxis include tingling in the lips, feet, or hands, flushing, tightness in the throat and chest, and difficulty breathing.
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only — they do not constitute endorsements of those other sites. Copyright 2004 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
Step 4: Should You See An Allergist?
For many people, their allergies are bad enough that they wonder if they should see an "allergist." You may even wonder what an allergist does. An allergist diagnoses, treats, and manages allergy-related conditions, like allergic rhinitis and asthma. In addition to being board-certified in pediatrics or internal medicine, most allergists are ABAI-certified. ABAI stands for "American Board of Allergy and Immunology." If your allergist is ABAI-certified, he or she completed a 2-3 year fellowship of specialized study in asthma, allergy, and immunology, and passed a certifying exam.
Through testing, an allergist can identify the allergens that cause your symptoms.
If you suspect you are allergic to something and you’ve never been diagnosed, ask your primary care physician to refer you to an allergist, and find out if you have insurance coverage before making an appointment.
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only — they do not constitute endorsements of those other sites. Copyright 2004 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
Step 5: Allergy Testing and Diagnosis
Allergy testing can let you know for certain which allergens are affecting you. Testing may reveal allergens that you didn’t even realize were causing you problems. Furthermore, testing is necessary if you wish to start any treatment for your allergies.
The allergist will ask questions about your medical history to determine whether allergies run in your family. He or she may ask detailed questions about your symptoms, what you did to treat those symptoms, and whether it worked. Once non-allergic conditions are ruled out and allergy is suspected, your allergist will perform a diagnostic allergy test.
Skin prick or scratch test
When most people go to the allergist for the first time, they want to know right away — "What am I allergic to?" Fortunately, skin testing can usually be done on your first visit, and you may get immediate answers to your questions. Ask your primary care physician and allergist how to prepare for the allergy tests.
The skin prick or scratch test is the most common and reliable test for most allergies. The procedure is fairly painless. A small needle or plastic device is used to lightly prick or scratch your back or forearm with a tiny amount of allergen. After 15-20 minutes, your allergist will be able to interpret the results by examining each spot where allergens were scratched or pricked into your skin. The spots where you are allergic will become red and swollen, and the others will remain normal.
Intradermal test
The intradermal test is done when the skin prick or scratch test results are unclear. It is similar to the prick or scratch test, but involves injecting a small amount of allergen under the skin using a needle.
Reactions to skin testing should clear up quickly. Because skin testing involves the injection of allergens under the skin, there is a small risk of anaphylaxis. For this reason, allergy skin testing should only be performed in a medical setting, with access to emergency treatment.
Blood test
The blood test or RAST (radioallergosorbent) test measures the levels of allergy antibody, IgE, produced when your blood is mixed with a series of allergens in a laboratory. If you are allergic to a substance, the IgE levels may increase in the blood sample. The blood test may be used if you have existing skin problems like eczema, if you’re on medications that are long-acting or you cannot stop taking, if you have a history of anaphylaxis, or if you prefer not to have a skin test. Some drawbacks of the blood test are the cost and the time required to wait for the results. Also, other conditions are associated with elevated IgE levels (e.g., HIV, skin diseases, and parasitic diseases), so the results are not always definitive and need to be compared to your allergy symptoms and medical history.
Challenge test
To confirm a food or drug allergy after a skin or blood test result is positive, your allergist may perform a challenge test. For the challenge test, you swallow a very small amount of the suspected allergen (e.g., milk or antibiotic). If there is no reaction, your allergist gradually gives you more until a reaction is noted. Due to the risk of a severe allergic reaction like anaphylaxis, challenge tests are done in a clinical setting and are only performed when absolutely necessary.
Snapshot of a Moving Picture
Most people think of specific allergies in black and white terms — something you either have or you don’t. A study published in the January 2002 issue of the American Journal of Respiratory and Critical Care Medicine emphasizes that the truth is much more complex. Being allergic to something is a continuum — and that continuum changes over time. Most (but not all!) food allergies get better over time. Most airborne allergies get more com
mon as children get older. Some allergies peak before puberty and then disappear. Others don’t even begin until puberty is over.
Furthermore, test results must be interpreted differently at different ages. Under age 1, a positive test is usually a true allergy, but a negative test does not tell you anything. In children over 3 or 4, the reverse tends to be true — a negative test means the child is probably not allergic to that substance, whereas a positive test does not necessarily mean that the substance causes symptoms for the child.
Most people who do get tested for allergies have a single round of skin testing. This can provide a valuable snapshot of allergies at a single moment in time, but this just "scratches the surface" of a child’s long-term allergy story.
Step 6: Overview of Allergy Treatment
Doctors use three general approaches to help people with allergies: advise them on ways to avoid the allergen as much as possible, prescribe or recommend medication to relieve symptoms, and provide ongoing education and communication. Although there is no cure for allergies, one of these strategies — or a combination of them — can usually provide relief from allergy symptoms.
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only — they do not constitute endorsements of those other sites. Copyright 2004 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

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