Although you may receive an asthma diagnosis at any age, most people will be diagnosed in childhood. Even though your physician is probably very familiar with the classic signs of asthma -- wheezing, chest tightness, shortness of breath, and cough -- an asthma diagnosis can be very difficult because of these general non-specific symptoms.
An asthma diagnosis requires:
- Presence of symptoms compatible with asthma.
- Objective measurement of decreased airflow in your lungs that either partially or completely improves spontaneously or with treatment.
Your doctor will also want to make sure that your asthma diagnosis is correct and the symptoms are really asthma and not another diagnosis mimicking asthma in your child. Your doctor will likely ask you a number of questions and order several tests.
Being worried that your child has an asthma diagnosis can be a really scary time. Knowing some of the questions your doctor may ask and some of the tests that may be ordered in diagnosing asthma will help you get the most out of your doctor's visit and alleviate some of the 'unknown' anxiety that going to the doctor can create.
- Classic Symptoms: If your child read the textbook before seeing your doctor, he or she would complain of the classic triad of cough, shortness of breath, and wheezing-a high pitched whistling when you breathe out. Your cough is characteristically 'dry,' non-productive, and will most commonly be worse at night. Some patients also describe the shortness of breath as a chest tightness or band-like feeling.
- Episodic Symptoms: Typically in asthma, your symptoms will come and go over time and your doctor will likely ask you to explain how quickly the symptoms came on and what led to relief of the symptoms. He or she may also ask you to think about specific triggers of past symptoms, such as exposures to allergens like dust, smoke or changes in the weather, such as cold air.
- Exercise Symptoms: Asthma symptoms brought on by exercise typically occurs after about 15 minutes of activity and resolves after resting for 30 minutes to an hour-- so the shortness of breath felt after walking up a flight of stairs that gets better in a few minutes is not likely exercise-induced asthma. Exercise symptoms are generally more severe and occur more commonly with exposure to cold air.
Allergic Symptoms and History: Asthma is more common in people with a family history of asthma, other allergies in their family, or certain atopic diseases-meaning prone to allergic illness, like hay fever. Your doctor will probably ask if your child has symptoms such as:
- Not being able to keep up with classmates in physical activity
- Chronic or nighttime cough in the absence of an infection
And if there is a history of atopic conditions such as:
- Hay fever
- Allergic rhinitis
- Atopic dermatitis
A history of any of these conditions in a patient with symptoms compatible with asthma makes asthma much more likely.
Your doctor will also likely ask about exposure to and occurrence of symptoms with certain allergens. He/ she will want to know if you develop symptoms when:
- You are around furry pets
- The pollen counts increase
- You are exposed to dusts and molds
- Wheezing: Characteristically, your physician will hear a high-pitched musical sound on expiration-when you breathe out or exhale-that is typical of, but not specific for asthma (meaning other conditions can also cause wheezing). You will probably, however, not wheeze all of the time and wheezing does not indicate how mild or severe your asthma is.
- Nasal Inflammation: A pale swelling of the nasal cavities suggests allergic rhinitis that can worsen asthma symptoms.
- Peak Expiratory Flow Rate (PEFR): PEFR, a measurement of airflow in your lungs, is measured with a simple hand held device that you forcefully exhale into. Your physician may have you keep a measurement record at home. You will develop a personal best PEFR that will tell you how well your asthma is controlled. You and your physician will develop a plan for what to do if your PEFR is below 80% of normal.
- Spirometry: A test similar to the PEFR that requires more advanced equipment and is usually done in your physician's office. This test allows your doctor to better determine the severity of your airflow obstruction.
- Bronchodilator Response: A characteristic of asthma is improvement after treatment with a bronchodilator, a fast-acting quick relief medication. Generally your doctor will repeat spirometry 10-15 minutes after treating you with a bronchodilator. Increases in airflow of 12% are considered positive and assist in making a diagnosis of asthma.
- Bronchoprovocation Challenge Testing: Just the opposite of looking for an improvement in lung function with a bronchodilator, bronchoprovocation testing attempts to provoke airflow obstruction after having you inhale an irritative substance. This testing is usually only done when persons present with atypical symptoms.
- Chest x-ray: Chest x-rays are usually normal in patients with asthma, but your physician may order one if you are presenting for the first time with wheezing. If asthma has gone undiagnosed for a long time, the chest x-ray may demonstrate hyperexpansion.
- Blood Tests: There are no diagnostic blood tests for asthma. Your health care provider may order some blood tests to help rule out other causes of your symptoms.
In order to make a diagnosis, your doctor will use a combination of history, physical exam, and tests to decide what treatment is appropriate for you.
Asthma. Centers For Disease Control and Prevention. Accessed December 23, 2008. http://www.cdc.gov/asthma/
Patient information UpToDate.com. Accessed December 23, 2008. Asthma symptoms and diagnosis in children
National Heart, Lung, and Blood Institute. Accessed: January 1, 2009. Expert Panel Report 3 (EPR3): Guidelines for the Diagnosis and Management of Asthma
Asthma. In Chest Medicine: Essentials Of Pulmonary And Critical Care Medicine. Editors: Ronald B. George, Richard W. Light, Richard A. Matthay, Michael A. Matthay. May 2005.