Asthma Lung Sounds

The practice of listening to the lung and heart sounds is medically known as auscultation. A doctor uses a stethoscope and carefully listens to the sounds. All the characteristics of the sound are important to the doctor: the frequency and pitch, the intensity, the quality (or timbre) of the sounds in relation to inhaling, exhaling, coughing, or talking. In the past, doctors had to rely on auscultation and other components of physical examination to diagnose asthma and other respiratory conditions. Thanks to advances in modern medicine, various investigations like X-rays, lab tests, and lung tests provide additional information to help confirm the diagnosis and rule out other conditions. 

Some of the lung sounds that suggest asthma can be heard without a stethoscope. Let’s review in this article some asthma lung sounds.  These are different from normal healthy lung sounds. If you or your child have asthma, you can keep track of these sound sounds and tell your doctor when you have the next appointment. 


This is the most common lung sound associated with asthma. The majority of people with asthma wheeze, although some don’t. Wheezing is a continuous, usually high pitch whistling noise that can be heard during inhale and exhale. When this noise develops, it means that there is something that narrows the airways and impairs the normal airflow. Wheezing can be heard with the stethoscope in all lung fields or only at the base.  Wheezing is also characteristic of chronic obstructive pulmonary disease (COPD), but a person can wheeze due to allergies, bronchitis, pneumonia, sleep apnea or a foreign object stuck in the windpipe. Click here to listen to a short video to hear how wheezing sounds. 


Stridor is a harsh, noisy, and squeaking sound that occurs with every breath. This sound can be easily heard without the stethoscope and comes from the upper airways. Stridor happens when something obstructs the airways and the airflow is significantly disrupted. There are three subtypes of stridor: inspiratory (which is heard during inhalation, suggesting an obstruction above the vocal cords)), expiratory (during exhale, suggesting a blockage in the windpipe), or biphasic (during both inhales and exhales). This sound typically improves with the administration of epinephrine which helps relax the airways and reduce swelling. Besides asthma, other conditions that cause stridor include croup, infections of the windpipe, foreign body aspiration, paralyzed vocal cords, and epiglottis. Click here to hear what stridor sounds like.


Rhonchi are rattling, snoring, continuous, low pitched wheezing sounds that develop when mucus and secretion are in excess in the larger airways. They are heard during the inspiration and expiration.  A strong cough often clears these secretions and improves the rhonchi. Asthma, as well as COPD, pneumonia, and cystic fibrosis, can cause rhonchi. Click here to listen to rhonchi.

Crackles (rales)

Crackles or rales are due to fluid accumulation in the smallest airways. These sounds are short, explosive, loud sounds that sound like rattling, bubbling, or clicking. Crackles can be fine ( which are shorter and higher in pitch, best heard at the base of the lungs) or coarse (lower and longer in duration sounds, typically heard in severe pulmonary edema and chronic bronchitis). Asthma,  pneumonia, pulmonary fibrosis, and infections of the airways can cause crackles. Click here to listen to crackles. 

Decreased  lung sounds and silent chest

A healthcare professional can detect these changes with the stethoscope. The lung sounds can’t be heard or are difficult to hear. Reduced lung sounds mean that the airflow is significantly reduced, as it happens during an acute attack of asthma. The so-called silent chest is even more dangerous, as the chest is so tight and congested that no sounds are heard with the stethoscope. A silent chest requires treatment right away to open the airways and allow normal breathing. 

Oher tests

During the auscultation, remember to breathe slowly and deeply through the mouth. Don’t be surprised if the doctor asks you to say certain words or phrases. If you are asked to say “ninety-nine”, this is a special test that evaluates the lung sounds called bronchophony. In normal conditions, the lungs muffle the words. However, if the sound is clear it indicates that the lungs may be filled with fluid mucus or blood. Another test involves auscultation of the lungs when the patient says an “e” sound. Normally, the sound should sound like an “e” but muffled. If there is fluid in the lungs, the sound will sound more like an” a”. 

As the symptoms of asthma vary from one day to another, so will the lung sounds change. This is why it is important to have regular follow-ups with the doctor if you have asthma. A healthcare professional will also listen to the heart, will take blood pressure, check for fever or perform other tests. Lung tests, X-rays, and other imaging techniques further complete the evaluation of the lungs. 

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