Lung Disease & Respiratory Health Center

Bacterial infections may develop after a viral illness, such as a cold or influenza, and are less common than viral illnesses. Bacterial infections may affect the upper or lower respiratory system. Symptoms tend to localize to one area. In the upper respiratory system, the most common sites of bacterial infections are the sinuses and throat. In the lower respiratory system, the most common site is the lungs (pneumonia).

Bacterial infections are more common in smokers, people exposed to secondhand smoke, and people with chronic lung disease (such as asthma or chronic obstructive pulmonary disease [COPD]) and other chronic medical problems. Antibiotics can effectively treat most bacterial infections.

Allergies

Allergies, especially hay fever, are another common respiratory problem. Symptoms include sneezing, clear runny drainage from the nose and eyes, itchy eyes or nose, and stuffy, congested ears and sinuses. The symptoms of allergies often last longer than a typical viral respiratory infection. For more information, see the topic Allergic Rhinitis.

Asthma

Asthma is a chronic disease of the respiratory system. It causes inflammation and narrowing in the tubes that carry air to the lungs (bronchial tubes). The inflammation leads to difficulty breathing, wheezing, tightness in the chest, and cough.

Asthma often begins during childhood and may last throughout a person's life. The cause of asthma is not clearly known. It is more common in people who also have allergies. For more information, see the topic Asthma in Children or Asthma in Teens and Adults.

Use the Check Your Symptoms section to decide if and when you should see a doctor.