question: Bronchitis: Bronchitis is an inflammation of the lining of your bronchial tubes, which carry air to and from your lungs. People who have bronchitis often cough up thickened mucus, which can be discolored. Bronchitis may be either acute or chronic. Often developing from a cold or other respiratory infection, acute bronchitis is very common. Chronic bronchitis, a more serious condition, is a constant irritation or inflammation of the lining of the bronchial tubes, often due to smoking. Acute bronchitis, also called a chest cold, usually improves within a week to 10 days without lasting effects, although the cough may linger for weeks. However, if you have repeated bouts of bronchitis, you may have chronic bronchitis, which requires medical attention. Chronic bronchitis is one of the conditions included in chronic obstructive pulmonary disease (COPD). For either acute bronchitis or chronic bronchitis, signs and symptoms may include: - Cough   - Production of mucus (sputum), which can be clear, white, yellowish-gray or green in color - rarely, it may be streaked with blood   - Fatigue   - Shortness of breath   - Slight fever and chills   - Chest discomfort If you have acute bronchitis, you might have cold symptoms, such as a mild headache or body aches. While these symptoms usually improve in about a week, you may have a nagging cough that lingers for several weeks. Chronic bronchitis is defined as a productive cough that lasts at least three months, with recurring bouts occurring for at least two consecutive years. If you have chronic bronchitis, you're likely to have periods when your cough or other symptoms worsen. At those times, you may have an acute infection on top of chronic bronchitis. See your doctor if your cough: - Lasts more than three weeks   - Prevents you from sleeping   - Is accompanied by fever higher than 100.4 F (38 C)   - Produces discolored mucus   - Produces blood   - Is associated with wheezing or shortness of breath Acute bronchitis is usually caused by viruses, typically the same viruses that cause colds and flu (influenza). Antibiotics don't kill viruses, so this type of medication isn't useful in most cases of bronchitis. The most common cause of chronic bronchitis is cigarette smoking. Air pollution and dust or toxic gases in the environment or workplace also can contribute to the condition. Factors that increase your risk of bronchitis include: - Cigarette smoke. People who smoke or who live with a smoker are at higher risk of both acute bronchitis and chronic bronchitis.   - Low resistance. This may result from another acute illness, such as a cold, or from a chronic condition that compromises your immune system. Older adults, infants and young children have greater vulnerability to infection.   - Exposure to irritants on the job. Your risk of developing bronchitis is greater if you work around certain lung irritants, such as grains or textiles, or are exposed to chemical fumes.   - Gastric reflux. Repeated bouts of severe heartburn can irritate your throat and make you more prone to developing bronchitis. Although a single episode of bronchitis usually isn't cause for concern, it can lead to pneumonia in some people. Repeated bouts of bronchitis, however, may mean that you have chronic obstructive pulmonary disease (COPD). During the first few days of illness, it can be difficult to distinguish the signs and symptoms of bronchitis from those of a common cold. During the physical exam, your doctor will use a stethoscope to listen closely to your lungs as you breathe. In some cases, your doctor may suggest the following tests: - Chest X-ray. A chest X-ray can help determine if you have pneumonia or another condition that may explain your cough. This is especially important if you ever were or currently are a smoker. - Sputum tests. Sputum is the mucus that you cough up from your lungs. It can be tested to see if you have illnesses that could be helped by antibiotics. Sputum can also be tested for signs of allergies. - Pulmonary function test. During a pulmonary function test, you blow into a device called a spirometer, which measures how much air your lungs can hold and how quickly you can get air out of your lungs. This test checks for signs of asthma or emphysema. Most cases of acute bronchitis get better without treatment, usually within a couple of weeks. Medications Because most cases of bronchitis are caused by viral infections, antibiotics aren't effective. However, if your doctor suspects that you have a bacterial infection, he or she may prescribe an antibiotic. In some circumstances, your doctor may recommend other medications, including: - Cough medicine. If your cough keeps you from sleeping, you might try cough suppressants at bedtime. - Other medications. If you have allergies, asthma or chronic obstructive pulmonary disease (COPD), your doctor may recommend an inhaler and other medications to reduce inflammation and open narrowed passages in your lungs. Therapies If you have chronic bronchitis, you may benefit from pulmonary rehabilitation - a breathing exercise program in which a respiratory therapist teaches you how to breathe more easily and increase your ability to exercise. To help you feel better, you may want to try the following self-care measures: - Avoid lung irritants. Don't smoke. Wear a mask when the air is polluted or if you're exposed to irritants, such as paint or household cleaners with strong fumes. - Use a humidifier. Warm, moist air helps relieve coughs and loosens mucus in your airways. But be sure to clean the humidifier according to the manufacturer's recommendations to avoid the growth of bacteria and fungi in the water container. - Consider a face mask outside. If cold air aggravates your cough and causes shortness of breath, put on a cold-air face mask before you go outside.