Asthma Health Article

Causes & symptoms

In most cases, asthma is caused by inhaling an allergen that sets off the chain of biochemical and tissue changes leading to airway inflammation, bronchoconstriction, and wheezing. Because avoiding (or at least minimizing) exposure is the most effective way of treating asthma, it is vital to identify which allergen or irritant is causing symptoms in a particular patient. Once asthma is present, symptoms can be set off or made worse if the patient also has rhinitis (inflammation of the lining of the nose) or sinusitis. When, for some reason, stomach acid passes back up the esophagus in a reaction called acid reflux, this condition also can make asthma worse. In addition, a viral infection of the respiratory tract can inflame an asthmatic reaction. Aspirin and drugs called beta-blockers, often used to treat high blood pressure, also can worsen the symptoms of asthma. But the most important inhaled allergens giving rise to attacks of asthma are:

• animal dander
• dust mites
• fungi (molds) that grow indoors

• cockroach allergens
• pollen
• occupational exposure to chemicals, fumes, or particles of industrial materials
• tobacco smoke
• air pollutants

In addition, there are three important factors that regularly produce attacks in certain asthmatic patients, and they may sometimes be the sole cause of symptoms. They are:

• inhaling cold air (cold-induced asthma)
• exercise-induced asthma (in certain children, asthma attacks are caused simply by exercising)
• stress or a high level of anxiety

Wheezing often is obvious, but mild asthmatic attacks may be confirmed when the physician listens to the patient's chest with a stethoscope. Besides wheezing and being short of breath, the patient may cough or report a feeling of tightness in the chest. Children may have itching on their back or neck at the start of an attack. Wheezing often is loudest when the patient exhales. Some asthmatics are free of symptoms most of the time but may occasionally be short of breath for a brief time. Others spend much of their days (and nights) coughing and wheezing until properly treated. Crying or even laughing may bring on an attack. Severe episodes often are seen when the patient gets a viral respiratory tract infection or is exposed to a heavy load of an allergen or irritant. Asthmatic attacks may last only a few minutes or can go on for hours or even days. Being short of breath may cause a patient to become very anxious, sit upright, lean forward, and use the muscles of the neck and chest wall to help breathe. The patient may be able to say only a few words at a time before stopping to take a breath. Confusion and a bluish tint to the skin are clues that the

oxygen supply is much too low and that emergency treatment is needed. In a severe attack, some of the air sacs in the lung may rupture so that air collects within the chest, which makes it even harder to breathe. The good news is that almost always, even patients with the most severe attacks will recover completely.