Allergic asthma may be confused with non-allergic forms of bronchitis. There are two different types of non-allergic bronchitis:

• Acute bronchitis. An infection of the bronchial tree due to a virus, bacteria or fungi. Many of the same viruses that cause common colds also cause bronchitis. Acute bronchitis is often a viral condition, which means it will not respond to antibiotics, and is contagious. Symptoms usually resolve after several days to a week, though coughing may persist for longer periods.
  
  
• Chronic bronchitis. A condition characterized by the overproduction of mucus by the cells lining the larger breathing tubes (bronchi). The mucus blocks the movement of air and contributes to the development of infections. Chronic bronchitis is defined by the presence of a mucus-producing cough most days of the month for at least three months of the year for two successive years without any other underlying disease to explain the cough. Smoking is the most common cause of chronic bronchitis. Chronic bronchitis symptoms also intensify when the individual is exposed to air pollutants.
  
  The treatment of chronic bronchitis is aimed at reducing the irritation in the bronchial tubes. Some patients with chronic bronchitis also have an acute bacterial infection that may be treated with antibiotics. Patients that are prescribed antibiotics will only take them until the bacterial infection is resolved, after which chronic bronchitis symptoms may still be present. Patients with chronic bronchitis should not take antihistamines as the medication dries the mucus in the chest and may cause breathing problems.
  
  Chronic bronchitis is often neglected until it is in an advanced state. Frequently the lungs have been seriously injured by the time the patient consults a physician.

Another condition that can mimic allergic asthma is chronic rhinosinusitis (also known as sinusitis), a chronic infection of the sinus cavities. The signs and symptoms of chronic rhinosinusitis include a yellow-green mucus discharge and chronic cough.