People may suffer from several symptoms of asthma, such as wheezing, coughing, or difficulty breathing, but that does not mean that they have asthma. There are other medical conditions whose symptoms may mimic asthma symptoms, therefore making the correct diagnosis of asthma difficult.

Sinusitis is a disease which often coexists with asthma. It involves inflammation of the sinuses, and may trigger nocturnal asthma. Other diseases which are commonly mistaken for asthma are bronchitis and emphysema. Bronchitis is a type of infection which is usually viral or bacterial of bronchi, the bigger airways (breathing tubes) in the lungs. The symptoms include wheezing and coughing and so can be mistaken for asthma. Smoking can bring about bronchitis, because the smoke forms a longstanding inflammation of the inner lining of the air passages of the lungs. Emphysema is a type of disease where there is a permanent destruction of alveoli, or air sacs, in the lungs. This causes the lungs to become less elastic, trapping air inside the lungs permanently, and reduces the lung’s ability to take in oxygen and release carbon dioxide.

There are other conditions, such as angina, heartburn, pulmonary embolism (a blood clot in the pulmonary artery of the lungs) and congestive heart failure. These are serious conditions, so coughing and wheezing in patients should be carefully investigated by doctors.