Allergy

Allergy

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Category : Health & Care

An allergy refers to an exaggerated reaction by our immune system in response to bodily contact with certain foreign substances. It is exaggerated because these foreign substances are usually seen by the body as harmless and no response occurs in non- allergic people. Allergic people’s bodies recognize the foreign substance and one part of the immune system is turned on. Allergy-producing substances are called “allergens.” Examples of allergens include pollens, dust mite, molds, danders, and foods. To understand the language of allergy it is important to remember that allergens are substances that are foreign to the body and can cause an allergic reaction in certain people. When an allergen comes in contact with the body, it causes the immune system to develop an allergic reaction in persons who are allergic to it. When you inappropriately react to allergens that are normally harmless to other people, you are having an allergic reaction and can be referred to as allergic or atopic. Therefore, people who are prone to allergies are said to be allergic or “atopic.”

alergy
Figure 1.Showing hives, a common allergic symptom.

Allergy Fact

  • It is estimated that 50 million North Americans are affected by allergic conditions.
  • The cost of allergies in the united states is more than $10 billion dollars yearly.
  • Allergic rhinitis (nasal allergies) affects about 35 million Americans, 6 million of whom are children.
  • Asthma affects 15 million Americans, 5 million of whom are children.
  • The number of asthma has doubled over the last 20 years.

Whats causes allergies?
wombThe 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 are substances that are capable of causing the production of antibodies. Antigens may or may not lead to an allergic reaction. Allergens are certain antigens that cause an allergic reaction and the production of IgE.

The aim of the immune system is to mobilize its forces at the site of invasion and destroy the enemy. One of the ways it does this is to create protective proteins called antibodies that are specifically targeted against particular foreign substances. These antibodies, or immunoglobulins (IgG, IgM, IgA, IgD), are protective and help destroy a foreign particle by attaching to its surface, thereby making it easier for other immune cells to destroy it. The allergic person however, develops a specific type of antibody called immunoglobulin E, or IgE, in response to certain normally harmless foreign substances, such as cat dander. To summarize, immunoglobulins are a group of protein molecules that act as antibodies. There are five different types; IgA, IgM, IgG, IgD, and IgE. IgE is the allergy antibody.

Who is at risk and why?
Allergies can develop at any age, possibly even in the womb. They commonly occur in children but may give rise to symptoms for the first time in adulthood. Asthma may persist in adults while nasal allergies tend to decline in old age. You may inherit the tendency to develop allergies, you may never actually have symptoms. It is clear that you must have a genetic tendency and be exposed to an allergen in order to develop an allergy. Additionally, the more intense and repetitive the exposure to an allergen and the earlier in life it occurs, the more likely it is that an allergy will develop.

What are common allergic conditions, and what are allergy symptoms and signs?
The parts of the body that are prone to react to allergies include the eyes, nose, lungs, skin, and stomach. Although the various allergic diseases may appear different, they all result from an exaggerated immune response to foreign substances in sensitive people. The following brief descriptions will serve as an overview of common allergic disorders

Allergic Rhinitis
Allergic rhinitis (“hay fever”) is the most common of the allergic diseases and refers to seasonal nasal symptoms that are due to pollens. Year round or perennial allergic rhinitis is usually due to indoor allergens, such as dust mites, animal dander, or molds. It can also be caused by pollens. Symptoms result from the inflammation of the tissues that line the inside of the nose (mucus lining or membranes) after allergens are inhaled. Adjacent areas, such as the ears, sinuses, and throat can also be involved. The most common symptoms include: Runny nose, Stuffy nose, Sneezing, Nasal itching (rubbing), Itchy ears and throat, Post nasal drip (throat clearing).

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.”

Asthma 455012551
Asthma is a breathing problem that results from the inflammation and spasm of the lung’s air passages (bronchial tubes). The inflammation causes a narrowing of the air passages, which limits the flow of air into and out of the lungs. Asthma is most often, but not always, related to allergies. Common symptoms include: Shortness of breath, Wheezing, Coughing, Chest tightness.

Allergic Eyes
Allergic eyes (allergic conjunctivitis) is inflammation of the tissue layers (membranes) that cover the surface of the eyeball and the undersurface of the eyelid. The inflammation occurs as a result of an allergic reaction and may produce the following symptoms: Redness under the lids and of the eye overall, Watery, itchy eyes, Swelling of the membranes.

9252684A-B789-A08C-83FB377964FBA8FFAllergic Eczema
Allergic eczema (atopic dermatitis) is an allergic rash that is usually not caused by skin contact with an allergen. This condition is commonly associated with allergic rhinitis or asthma and features the following symptoms: Itching, redness, and or dryness of the skin, Rash on the face, especially children, Rash around the eyes, in the elbow creases, and behind the knees, especially in older children and adults.

Hives
hivesHives (urticaria) are skin reactions that appear as itchy swellings and can occur on any part of the body. Hives can be caused by an allergic reaction, such as to a food or medication, but they also may occur in non-allergic people. Typical hive symptoms are: Raised red welts, Intense itching

Allergic Shock
Allergic shock (anaphylaxis or anaphylactic shock) is a lifethreatening allergic reaction that can affect a number of organs at the same time. This response typically occurs when the allergen is eaten (for example, foods) or injected (for example, a bee sting). Some or all of the following symptoms may occur: Hives or reddish discoloration of the skin, Nasal congestion, Swelling of the throat, Stomach pain, nausea, vomiting, Shortness of breath, wheezing, Low blood pressure or shock.

Prevention of Allergic Reactions
Most people learn to recognize their allergy triggers; they also learn how to avoid them. An allergy specialist (allergist) may be able to help you identify your triggers. Several different types of allergy tests are used to identify triggers. Skin testing is the most widely used and the most helpful. There are several different methods, but all involve exposing the skin to small amounts of various substances and observing the reactions over time. Blood tests (RAST) generally identify IgE antibodies to specific antigens. Other tests involve eliminating certain allergens from your environment and then reintroducing them to see if a reaction occurs.

Allergic Reaction Diagnosis
For typical allergic reactions, your health-care provider will examine you and ask questions about your symptoms and their timing. Blood tests and X-rays are not needed except under unusual circumstances. In case of severe reactions, you will be evaluated quickly in the emergency department in order to make a diagnosis. The first step for the health-care provider is to judge the severity of the allergic reaction.

  • Blood Pressure and pulse and Checked.
  • An examination determines whether you need help breathing.

Skin Test
Skin testing is also known as “puncture testing” and “prick testing” due to the series of tiny puncture or pricks made into the patient’s skin. Small amounts of suspected allergens and/or their extracts (pollen, grass, mite proteins, peanut extract, etc.) are introduced to sites on the skin marked with pen or dye (the ink/dye should be carefully selected, lest it cause an allergic response itself ). A small plastic or metal device is used to puncture or prick the skin.