Asthma is common, and exacerbation at work may be coincidental. A number of disorders may cause some or all of the symptoms of asthma. Asthma, chronic bronchitis, and emphysema all affect the lungs in similar ways and, in fact, may all be present in the same person. Unlike the other two conditions, however, asthma usually first appears in patients less than 30 years old and is not revealed by abnormal chest x-rays. Other diseases that must be considered during diagnosis are respiratory tract infections, pulmonary embolism, cancer, heart failure, tumors, psychosomatic illnesses, and certain rare disorders.
Panic disorder can coincide with asthma or be confused with it.
If symptoms and a patient's history are indicative of asthma, the physician will usually perform pulmonary function tests to confirm the diagnosis and determine the severity of the disease. The challenge test is not always accurate, particularly in patients whose only asthmatic symptom is persistent coughing. It may be quite useful in ruling out occupational asthma. Another method for inducing airway resistance is to administer cold air. Although this so-called cold air hyperventilation test is very accurate for ruling out asthma, it is not sensitive enough to accurately identify adults who actually are asthmatic.