Diagnosis of asthma...

In most cases, a physician can diagnose asthma on the basis of typical findings in a patient's clinical history and examination.

Asthma is strongly suspected if a patient suffers from eczema or other allergic conditions (as asthma and eczema tend to go together) or if the patient has a family history of asthma. While measurement of airway function is possible for adults, most new cases are diagnosed in children who are unable to perform such tests. Diagnosis in children is based on a careful compilation and analysis of the patient's medical history and subsequent response to drug treatment. In adults, diagnosis can be made with a peak flow meter (which tests airway restriction).

Testing peak flow at rest (or baseline) and after exercise can be helpful, especially in young asthmatics who may experience only exercise-induced asthma. If the diagnosis is in doubt, a more formal lung function test may be conducted. Once a diagnosis of asthma is made, a patient can use peak flow meter testing to monitor the severity of the disease.

Before diagnosing someone as asthmatic, alternative possibilities should be considered, such as chronic obstructive pulmonary disease, which closely resembles asthma. Aspiration, whether direct due to swallowing disorder or indirect (due to acid reflux), can show similar symptoms to asthma.

Only a minority of asthma sufferers have an identifiable allergy trigger. The majority of these triggers can often be identified from what the patient tells the doctor; for instance, asthmatics with hay fever or pollen allergy will have seasonal symptoms, those with allergies to pets may experience an improvement in symptoms when away from home, and those with occupational asthma may improve during leave from work. Occasionally, allergy tests are warranted and, if positive, may help in identifying avoidable symptom triggers.