An asthma diagnosis is based on several factors, including a detailed medical history, a physical exam, your symptoms, and overall health and test results.

The first step in diagnosing asthma is talking to your healthcare team about your symptoms and your health. This can provide clues as to whether asthma or something else is causing your symptoms. Your care team will likely ask about your symptoms and your exposure to substances that have been linked to asthma. Questions might include:

• What are your symptoms? When do they occur? What, if anything, seems to trigger them?
• Are you often exposed to tobacco smoke, chemical fumes, dust or other airborne irritants?
• Do you have hay fever or another allergic condition?
• Do you have blood relatives, such as a parent, aunt, grandparent or cousin, with asthma, hay fever or other allergies?
• What health problems do you have?
• What medications or herbal supplements do you take?
• What is your occupation?
• Do you have pet birds, or do you raise pigeons?

Your healthcare professional may:

• Examine your nose, throat and upper airways.
• Use a stethoscope to listen to your breathing. Wheezing — high-pitched whistling sounds when you breathe out — is one of the main signs of asthma.
• Examine your skin for signs of allergic conditions such as eczema and hives.

Your healthcare professional will want to know whether you have common symptoms of asthma, such as:

• Recurrent wheezing.
• Coughing.
• Trouble breathing.
• Chest tightness.
• Symptoms that occur or worsen at night.
• Symptoms that are triggered by cold air, exercise or exposure to allergens.

Asthma symptoms in children

In children, additional symptoms may signal asthma. These may include:

• Louder or faster than usual breathing.
• Frequent coughing or coughing that worsens after active play.
• Coughing, clear mucus and a runny nose caused by hay fever.
• Frequent missed school days.
• Limited participation in physical activities.

If your healthcare professional suspects that you have a condition in addition to or other than asthma, you may need tests such as:

• X-ray or computerized tomography (CT) imaging of your chest.
• CT scans of your sinuses.
• Blood tests.
• Gastroesophageal reflux assessment.
• Testing of the phlegm in your lungs for signs of a viral or bacterial infection.

Your care professional also may want to see whether you have other conditions that often happen with asthma and can worsen symptoms. These include:

• Heartburn, also known as gastroesophageal reflux disease or GERD.
• Hay fever.
• Sinusitis.

Your healthcare professional also may perform allergy tests. These can be skin tests, blood tests or both. Although not used to diagnose asthma, allergy tests can help identify an allergic condition, such as hay fever, that may be causing your symptoms or worsening existing asthma.

Sometimes, diagnosing the cause of breathing problems is a challenge. It can be difficult to tell asthma from other conditions — particularly in young children.

When asthma happens with another condition that affects breathing, it can further complicate diagnosis.

Even if a diagnosis isn't certain, your care professional may prescribe medicines or other treatment to see what helps. It may take time — and patience — to get the correct diagnosis and decide on the best course of treatment.