Asthma
Definition and Overview
Asthma is a chronic disease that affects the airways of the lungs. It is characterized by inflammation and narrowing of the bronchial tubes, leading to episodes of wheezing, shortness of breath, chest tightness, and coughing. Asthma affects people of all ages, but it most often starts during childhood. In the United States, more than 25 million people are known to have asthma, about 7 million of whom are children.
Causes and Risk Factors
The exact cause of asthma is unknown, but it is thought to be caused by a combination of genetic and environmental factors. Some people may be genetically predisposed to developing asthma, while others may develop it as a result of exposure to certain environmental factors. Risk factors for developing asthma include having a family history of the disease, having another allergic condition (such as atopic dermatitis or allergic rhinitis), being overweight, and smoking or exposure to secondhand smoke.
Symptoms and Diagnosis
The symptoms of asthma can vary from person to person and can range from mild to severe. Common symptoms include coughing, wheezing, shortness of breath, and chest tightness. These symptoms are often worse at night or early in the morning.
Diagnosis of asthma typically involves a physical examination, a review of symptoms, and lung function tests. The most common lung function test is spirometry, which measures how much air a person can exhale and how quickly. Other tests may include a peak flow test, which measures how hard a person can breathe out, and a methacholine challenge test, which involves inhaling a substance that causes the airways to spasm and then measuring lung function.
Treatment and Management
While there is no cure for asthma, the condition can be managed with medication and lifestyle changes. The goal of treatment is to control the symptoms and prevent asthma attacks. Medications used to treat asthma can be divided into two categories: long-term control medications, which are taken daily to control inflammation and prevent symptoms, and quick-relief medications, which are used to treat symptoms during an asthma attack.
Long-term control medications include inhaled corticosteroids, long-acting beta agonists, leukotriene modifiers, and theophylline. Quick-relief medications include short-acting beta agonists, ipratropium, and oral and intravenous corticosteroids.
Lifestyle changes that can help manage asthma include avoiding triggers, such as allergens and irritants, and maintaining a healthy lifestyle with regular exercise and a balanced diet.