Asthma and allergy
Asthma attacks (worsening of asthma symptoms) can be triggered by allergies, which can temporarily increase the inflammation of the airways in a susceptible person. Allergy is the leading cause of asthma, and about 90% of children under the age of 10 with asthma have allergies. About 70% of people under 30 with asthma and 50% of those over 30 with asthma also have allergies. In relation to the home environment, triggers can be grouped into two primary categories:
allergens and irritants. Allergens are typically defined as something that causes an allergic reaction in some people, but not others. Indoor allergens include dust mites, cockroach debris, pet dander, and mold. Irritants are substances that irritate the respiratory tract and include tobacco smoke and paint fumes.
Allergies are the immune system's reaction when exposed to what is otherwise a harmless substance, such as plant pollen, mold or animal hair, skin or saliva. For people with allergies, the immune system treats these substances, called "allergens," as if they are harmful, causing a disruption to normal body functions. Allergies cause the body to have a physical response to substances known as allergens. When this response occurs, the immune system is overreacting to a substance that does not cause any reaction at all in most people.
Essentially, an allergic reaction occurs when the body sends a signal to the immune system that a harmful substance is present. When one of these substances enters the body -- pollen, for example -- the person with an allergy develops an excess of an antibody called immunoglobulin E. These antibodies react with allergens to release histamines. It’s the histamines that produce allergic symptoms (stuffy nose, sneezing, etc.). If a person has allergies, his immune system reacts to these allergens as if the allergens were invading the body. To fight the allergen, his immune system produces an antibody called immunoglobulin E (IgE). If the IgE combines with the allergen, this sets a process in motion that results in the release of certain substances in the body. One of the substances released is histamine, which causes allergic symptoms that can affect the eyes, nose, throat, skin, gastrointestinal tract, or lungs. When the airways in the lungs are affected, symptoms of asthma (such as coughing, wheezing, or difficulty breathing) can occur when the body is exposed to the allergen.
An Allergy is a response to a substance, called allergens, that produce a reaction in the body. When the immune system is exposed to allergens, it produces antibodies which attach themselves to certain cells in the body called "mast cells." These mast cells see the invading particle as a threat and release substances such as Histamine to destroy the intruder particle, but these substances also produce undesirable allergic reactions. When the reaction takes place in the nose and sinuses, it is called Hay Fever or allergic rhinitis. When the reaction to allergens occurs in the skin it is called Hives. An allergic reaction that occurs over the whole body can be life threatening and is called Anaphylaxis. A reaction in the stomach is a Food Allergy and when an allergic reaction due to allergens happens in the lungs, it is called allergic Asthma. Asthma is a chronic illness that causes breathing problems and is considered a lung disease. The rarest type of allergic reaction is called anaphylactic shock. This is a severe reaction that can affect many organs at once. Symptoms include rapid decrease in blood pressure, rash or hives, difficulty breathing, abdominal pain, swollen tongue or throat, diarrhea, fainting and sometimes.
Many different substances cause allergic reactions. Some are toxic, such as exhaust fumes, and others are non-toxic, like pollen and food. The most common allergens include pollen from trees, grasses and weeds, dust mite particles, cockroaches, tobacco smoke, paint fumes, gasoline fumes, pet dander (skin, saliva, hair or fur), mold spores, and foods (most commonly, peanuts, shellfish, milk, eggs and wheat). Parents who have allergies or asthma often pass along the tendency to have these conditions to their kids.
An allergy is an abnormal reaction by the body to substances which it is sensitized to. These substances are called allergens, and an allergic person produces antibodies against these allergens. Each time the allergic person comes in contact with an allergen after that first contact, certain cells in the body release chemical substances called mediators. Mediators, like histamine and leukotrienes, can cause one or more of the following symptoms: redness, swelling, itching and increased mucous production. With an allergy to pollens, there may be itchy eyes and runny nose. With an allergy to cats, there may be itchy eyes and swelling in the lungs.