Diagnosis of asthma
A diagnosis of asthma is usually made on the basis of history (variable symptoms of cough, wheeze and breathlessness) and confirmation of airway narrowing that is variable or can be reversed (usually by peak flow tests over time or before and after a reliever inhaler). Depending on age it may be important to rule out other lung diseases such as infections or inhaled objects in children or COPD (smoking related fixed airway narrowing) in older adults. A chest X-ray is usually not required to diagnose asthma but may be helpful in excluding other causes of symptoms. Asthma is often seen together with rhinitis or nasal inflammation and detection and treatment of this may help.
Skin prick tests may be helpful to confirm allergic sensitisation.
Investigation of Asthma
If you have asthma this should be assessed by your doctor or an asthma nurse. Investigation will include a history of your symptoms, whether asthma wakes you at night, what provokes them, your work, family history, any history of asthma attacks or admissions to the emergency room or hospital. If you have a history of allergens (cats, dogs, dust, pollens etc) as triggers for asthma symptoms it may be appropriate to have an allergy opinion and skin prick tests. Blowing tests including peak flow (how fast you can blow air out of the lungs) and spirometry (how much air you can blow out in a fixed time and in total) are helpful in assessing asthma and you may be asked to record these in a diary at home.