Asthma is an inflammatory disorder of the airways, which causes attacks of wheezing, shortness of breath, chest tightness, and coughing.

Alternative Names
Bronchial asthma; Exercise-induced asthma

CAUSES:
Asthma is caused by inflammation in the airways. When an asthma attack occurs, the muscles surrounding the airways become tight and the lining of the air passages swell. This reduces the amount of air that can pass by, and can lead to wheezing sounds.

In fact the exact cause of asthma is unknown. Asthma is most likely caused by a combination of genetic (inherited) factors and environmental triggers (such as allergens and infections). Asthma tends to run in families, so children whose parents have asthma are more likely to develop it themselves.

*The Allergic Response

Nearly half of adults with asthma have an allergy-related condition, which, in most cases developed first in childhood. (In patients who first develop asthma during adulthood, the allergic response usually does not play a strong causal role.)

In people with allergies, the immune system overreacts to exposure to allergens. Allergic asthma is triggered by inhaling certain substances (allergens) such as:

*Dust mites, specifically mite feces, which are coated with enzymes that contain a powerful allergen. These are the primary allergens in the home.

*Animal dander. Cats harbor significant allergens, which can even be carried on clothing; dogs usually cause fewer problems. People with asthma who already have pets and are not allergic to them probably have a low risk for developing such allergies later on.

*Molds.

*Cockroaches. Cockroach dust is a major asthma trigger and may reduce lung function even in people without a history of asthma.

*Pollen, from plants.

*Environmental Factors (Irritants)

*An asthma attack can also be induced or aggravated by direct irritants to the lungs. Important irritants involved in asthma include cigarette smoke, indoor chemicals, and air pollution.

*Infections. Respiratory viral and bacterial infections play a role in some cases of adult-onset asthma. In both children and adults with existing allergic asthma an upper respiratory tract infection often worsens an attack.


EXAMS AND TESTS

Allergy testing may be helpful in identifying allergens in people with persistent asthma. Common allergens include pet dander, dust mites, cockroach allergens, molds, and pollens. Common respiratory irritants include tobacco smoke, pollution, and fumes from burning wood or gas.

A stethoscope is used to listen to the lungs. Asthma-related sounds may be heard. However, lung sounds are usually normal between asthma episodes.

Tests may include:

*Arterial blood gas
*Blood tests to measure eosinophil count (a type of white blood cell) and IgE (a type of immune system protein called an immunoglobulin)
*Chest x-ray
*Lung function tests
*Peak flow measurements


SYMPTOMS

*Cough with or without sputum (phlegm) production

*Pulling in of the skin between the ribs when breathing (intercostal retractions)

*Shortness of breath that gets worse with exercise or activity
*Wheezing

Comes in episodes
May be worse at night or in early morning
May go away on its own
Gets better when using drugs that open the airways (bronchodilators)
Gets worse when breathing in cold air
Gets worse with exercise
Gets worse with heartburn (reflux)
Usually begins suddenly


Emergency Symptoms

Bluish color to the lips and face

Decreased level of alertness such as severe drowsiness or confusion, during an asthma attack

Extreme difficulty breathing

Rapid pulse

Severe anxiety due to shortness of breath

Sweating

Additional symptoms that may be associated with this disease:

Abnormal breathing pattern --breathing out takes more than twice as long as breathing in
Breathing temporarily stops
Chest pain
Nasal flaring
Tightness in the chest


TREATMENT

The goal of treatment is to avoid the substances that trigger your symptoms and to control airway inflammation.

There are two basic kinds of medication for the treatment of asthma:

*Long-acting medications to prevent attacks
*Quick-relief medications for use during attacks

Long-term control medications are used on a regular basis to prevent attacks, not to treat them. Such medicines include:

Inhaled corticosteroids (such as Azmacort, Vanceril, AeroBid, Flovent) prevent inflammation
Leukotriene inhibitors (such as Singulair and Accolate)
Long-acting bronchodilators (such as Serevent) help open airways
Omilizumab (Xolair), which blocks a pathway that the immune system uses to trigger asthma symptoms
Cromolyn sodium (Intal) or nedocromil sodium (Tilade)
Aminophylline or theophylline (not used as frequently as in the past)
Sometimes a single medication that combines steroids and bronchodilators are used (Advair, Symbicort)

Quick relief, or rescue, medications are used to relieve symptoms during an attack. These include:

Short-acting bronchodilators (inhalers), such as Proventil, Ventolin, Xopenex, and others
Corticosteroids, such as methylprednisolone, may be given directly into a vein (intravenously), during a severe attack, along with other inhaled medications
People with mild asthma (infrequent attacks) may use quick relief medication as needed. Those with persistent asthma should take control medications on a regular basis to prevent symptoms.

A severe asthma attack may require a hospital stay, oxygen, and medications through a vein (IV).

A peak flow meter is a simple device to measure how quickly you can move air out of your lungs. It can help you see if an attack is coming, sometimes even before any symptoms appear. Peak flow measurements can help show when medication is needed, or other action needs to be taken. Peak flow values of 50-80% of a specific person's best results are a sign of a moderate asthma attack, while values below 50% are a sign of a severe attack.


PREVENTION

Asthma symptoms can be substantially reduced by avoiding known triggers and substances that irritate the airways.

Bedding can be covered with "allergy proof" casings to reduce exposure to dust mites. Removing carpets from bedrooms and vacuuming regularly is also helpful. Detergents and cleaning materials in the home should be unscented.

Keeping humidity levels low and fixing leaks can reduce growth of organisms such as mold. Keep the house clean and keep food in containers and out of bedrooms -- this helps reduce the possibility of cockroaches, which can trigger asthma attacks in some people.

If a person is allergic to an animal that cannot be removed from the home, the animal should be kept out of the patient's bedroom. Filtering material can be placed over the heating outlets to trap animal dander.

Eliminating tobacco smoke from the home is the single most important thing a family can do to help a child with asthma. Smoking outside the house is not enough. Family members and visitors who smoke outside carry smoke residue inside on their clothes and hair -- this can trigger asthma symptoms.

Persons with asthma should also avoid air pollution, industrial dusts, and other irritating fumes, as much as possible.