Lung sounds in asthma

Rhonchi or Rales? Important Lung Sounds Made Easy: A Practical Guide (With Full Audio)

Lung Sounds Made Easy

From the general practice nurse to the ICU nurse, lung sounds tell you a great deal about a patient and their relative health. However, knowing the difference between rales, a crackle, and a wheeze is sometimes still a confusing proposition for many nurses, especially new nurses.

Part of the reason for that is that some of the language is interchangeable. For instance, crackles actually are rales, and the large amount of words can leave anyone’s head spinning. Knowing what to call what you hear on the other end of the stethoscope can tell you – and the doctor – quite a bit about a patient’s condition.


What was once called rhonchi are now called a sonorous wheeze, and this is because they have a snoring, gurgling quality to them. Rhonchi are often a low-pitched moan that is more prominent on exhalation. It differs from wheezes in that wheezes are high and squeaky while these are low and dull. Rhonchi are caused by blockages to the main airways by mucous, lesions, or foreign bodies. Pneumonia, chronic bronchitis, and cystic fibrosis are patient populations that commonly present with rhonchi. Coughing can sometimes clear this breath sound and make it change to a different sound.

Crackles (Rales)

Crackles are the sounds you will hear in a lung field that has fluid in the small airways. As stated before, crackles and rales are the same thing, and this can often lead to confusion among health care providers. Crackles come in two flavours: fine and coarse. Fine crackles sound like salt heated on a frying pan or the sound of rolling your hair between your fingers next to your ear. Coarse crackles sound like pouring water out of a bottle or like ripping open Velcro. This lung sound is often a sign of adult respiratory distress syndrome, early congestive heart failure, asthma, and pulmonary oedema.

Rhonchi, rales, wheezes, rubbing or stridor? – Listening for lung sounds.


Wheezes and rhonchi are actually very closely related. They are so closely related that the terminology for them has changed, too. Wheezes are now known as sibilant wheezes to distinguish them from rhonchi. Sibilant wheezes are high-pitched and shrill sounding breath sounds that occur when the airway becomes narrowed. They often have a musical quality to them. These are the typical wheezes heard when listening to an asthmatic patient. Sibilant wheezes are caused by asthma, congestive heart failure, chronic bronchitis, and COPD (see ‘Understanding COPD and the Hypoxic Drive to Breathe‘).


Stridor is an unusual sound that not many adult patients will have, but it bears mentioning. It is a high-pitched, musical sound that is heard over the upper airway. It usually indicated a foreign body obstruction of the larger airways, such as the trachea or a main bronchus, and requires immediate attention. It is also the most common type of breath sound heard in children with croup, though it is important to differentiate between croup and a foreign body airway obstruction.


A pleural friction rub is caused by the inflammation of the visceral and parietal pleurae. These membranes are usually coated in a protective fluid, but when inflamed, they stick together and make a sound like leather creaking against itself. It often causes a great deal of pain, and the patient will splint their chest and resist breathing deeply to help mitigate the pain. A pericardial rub and a pleural rub will often sound similar, and the best way to distinguish between the two is to make the patient hold their breath. If you still hear the rubbing sound, then the patient has a pericardial rub and requires different treatment. Pleural effusion and pneumothorax are two diagnoses that can cause a pleural friction rub.

Physical Exam

A physical exam is an important part of diagnosing any medical condition. At your appointment, your doctor ask you about your symptoms and personal and medical history. Specifically, they will ask about your symptoms, lifestyle, family history and medical conditions.

For example, if you have a family history of asthma, allergies or skin allergies, that means you have a chance of also having these conditions. This tells the doctor that they should look for signs of asthma. If they think you might have asthma based on the information you give them, they will do a physical exam.

During a physical exam for asthma or allergies, your doctor will look at your ears, nose, throat, eyes, skin, chest and lungs. They may:

  • Listen to your lungs for wheezing or whistling that could mean inflammation
  • Look in your nose and throat for swelling and drainage that could be caused by allergies
  • Check your skin for signs of atopic dermatitis, also called eczema
  • Take an X-ray of your lungs and sinuses
  • Perform tests to rule out other conditions

If your doctor finds signs of asthma, they will discuss with you about options for lung tests. There are several types of lung function tests.

If your doctor thinks you have allergic asthma – asthma triggered by things you are allergic to – they may encourage you to do allergy testing as well.
Medical Review December 2017.

A Physical Exam for Asthma Diagnosis

If you suspect that you have adult asthma, you will likely go see your doctor. And though a doctor has many tools at his disposal to make an asthma diagnosis, one of the first he will employ is a physical exam.

Are you doing everything you can to manage your asthma? Find out with our interactive checkup.

“An asthma exam is not much different from a regular exam,” says Anatoly Belilovsky, MD, a pediatrician in private practice in New York City. “What we do to look for signs of asthma — listening with a stethoscope, observing the breathing effort, etc. — would be a part of most exams.”

Asthma Diagnosis: Physical Exam Step by Step

The physical exam is just one tool — along with your medical history and other testing — that the doctor will use to determine whether or not you have asthma. Ronald M. Ferdman, MD, an assistant professor of pediatrics at the University of Southern California, says that the typical physical examination usually consists of numerous steps, including:

  • Overall health. Your doctor will perform an overall assessment to get a general sense of whether or not you are in robust health or are an acutely ill person.
  • Ear exam. He’ll examine your ears to look for signs of infection or chronic fluid.
  • Eye exam. In this examination, your doctor will look for redness, swelling, inflammation, or discharge. He’ll also take a closer look at the skin around your eyes for signs of eczema, dark circles under your eyes (“allergic shiners”), or folds of skin under the eye (“Dennie’s lines”).
  • A look at your nose. This includes an examination of both the inside and outside of your nose. Your doctor will look for swelling of normal structures on the inside of the nose (“turbinates”). He will also check the color and consistency of the nasal lining and amount, color, and consistency of nasal discharge. Finally, he’ll look for signs of bleeding; assess nasal septum deviation, color, or damage (perforation); and look for abnormal structures such as a nasal polyp or a foreign body (like a bead, eraser, etc.). The exam of the outside of your nose is to look for a horizontal crease across the lower one-third of the nose (called an “allergic crease”). In addition, your doctor will watch for itching of the nose (“allergic salute”).
  • Mouth exam. Your doctor will look in your mouth to assess the health and hygiene of your gums and teeth; look for post-nasal drip (amount, color, consistency); and check for redness or inflammation of your throat, and the size and quality of your tonsils.
  • Neck check. This is a quick feel of your neck for signs of abnormally swollen lymph nodes or enlarged thyroid.
  • Heart check. Your doctor will listen to your heart for abnormal sounds (murmurs) or rhythm.
  • Lung exam. He’ll also listen to your lungs (front and back of the chest) for wheezes, crackles, congestion, or any other abnormal sounds. Also, he will likely have you do different breathing maneuvers (deep breaths, blow out breath, etc.) while he listens.
  • Chest. Your doctor will take a look at your chest to see if it is normally shaped and moving symmetrically, and to see if there are retractions (use of extra muscles to breathe), which indicate difficulty breathing.
  • Abdomen. He’ll feel your abdomen for pain or tenderness, signs of an enlarged liver or spleen, or any other abnormal masses. He will also listen for normal bowel sounds.
  • Skin exam. This examination of the skin is to look for any new rashes or birth marks. Your doctor also might rub some of your birthmarks to see if they change with pressure.
  • Not routine. Doctors typically don’t examine genitalia, do a rectal exam, or a complete detailed neurological or developmental exam unless there is a specific reason to do so based on the medical history or any abnormal findings on the exam.
  • Return visits. For return visits, your doctor will probably do a more targeted H.E.E.N.T. (head, ear, eye, nose, throat exam), as well as neck, lung, heart, and skin exams.

What Your Doctor Is Looking For

As you can see from this step-by-step breakdown, your doctor is checking a lot more than just your lung capacity during this physical exam. But he is not only looking for any signs or symptoms of asthma, but also allergies, as well as any other conditions that the breathing difficulty might be related to, instead of asthma.

As your doctor listens to your lungs, though, a lot of information will be gathered about whether you might have asthma. The simple answer is that your doctor is listening to hear how well you breathe, but of course, there is a lot more to it than that.

“When checking breath sounds, we are looking for any signs of abnormal breathing,” says Dr. Ferdman. “The classic sound heard in asthma is ‘wheezing,’ which is a high-pitched, whistle-like sound heard mostly upon expiration. It can be both expiratory and inspiratory as the wheezing becomes more severe. Sometimes it is so mild that we will only hear it if the person forcibly exhales, which is one of the reasons we ask our patients to do different breathing maneuvers,” he says.

Of course, that’s not the only sound that your doctor is listening for. “We listen for ‘crackles’ (used to be called ‘rales’), which sound like Velcro being pulled apart,” adds Ferdman. “This sound is typically heard with pneumonias but can occasionally be heard in asthma. We also listen for ‘rhonchi,’ which are like deeper ‘rumbling’ sounds usually suggestive of mucus in the lungs.”

Finally, your doctor will time how long you inhale and exhale because with asthma, the inhalation period is shorter than exhalation. He will also make sure breath is moving freely through all areas of the lungs, and that your lungs fill and empty symmetrically. If he suspects pneumonia or another non-asthma problem, he may even tap the chest wall briskly in different areas to compare the sounds. Or he might have you make audible sounds, so that he can hear what it sounds like through the chest wall. All of these techniques will help your doctor narrow in on whether you have adult asthma.

Learn more in the Everyday Health Asthma Center.

Breath sounds

The lung sounds are best heard with a stethoscope. This is called auscultation.

Normal lung sounds occur in all parts of the chest area, including above the collarbones and at the bottom of the rib cage.

Using a stethoscope, the doctor may hear normal breathing sounds, decreased or absent breath sounds, and abnormal breath sounds.

Absent or decreased sounds can mean:

  • Air or fluid in or around the lungs (such as pneumonia, heart failure, and pleural effusion)
  • Increased thickness of the chest wall
  • Over-inflation of a part of the lungs (emphysema can cause this)
  • Reduced airflow to part of the lungs

There are several types of abnormal breath sounds. The 4 most common are:

  • Rales. Small clicking, bubbling, or rattling sounds in the lungs. They are heard when a person breathes in (inhales). They are believed to occur when air opens closed air spaces. Rales can be further described as moist, dry, fine, or coarse.
  • Rhonchi. Sounds that resemble snoring. They occur when air is blocked or air flow becomes rough through the large airways.
  • Stridor. Wheeze-like sound heard when a person breathes. Usually it is due to a blockage of airflow in the windpipe (trachea) or in the back of the throat.
  • Wheezing. High-pitched sounds produced by narrowed airways. Wheezing and other abnormal sounds can sometimes be heard without a stethoscope.

Different Types of Lung Sounds

Hi, and welcome to this video on lung sounds. Lung sounds, or breath sounds, refer to the sounds heard when air moves through the respiratory system. These are easily identified by auscultation, or listening to the lungs fields with the stethoscope. The lung sounds are classified according to the sounds involved during inhalation and exhalation phases of the breath cycle, taking note of the pitch and intensity.

Types of abnormal breath sounds include wheezing, rhonchi (which sound like low-pitched wheezing), stridor, crackles (also known as rales, and these may be further classified as fine or coarse) and pleural friction rub. Let’s start with wheezing. Wheezing is caused by the narrowing of the airways and is associated with asthma, bronchitis, pneumonia, COPD, smoking, heart failure, inhaling a foreign object into the lungs, or an allergic reaction.

Wheezing sounds may occur during inhalation or exhalation and are continuous with a musical quality. The classic wheeze refers to the high-pitched whistle-like sound heard during exhalation as air moves through a narrow or obstructed airway. Listen to the following wheezing lungs sounds. A wheeze may also be lower-pitched, having a snoring or moaning quality in which they are referred to as rhonchi.

Rhonchi sounds have a continuous snoring, gurgling, or rattle-like quality. Rhonchi occur in the bronchi as air moves through tracheal-bronchial passages coated with mucus or respiratory secretions. This is often heard in pneumonia, chronic bronchitis, or cystic fibrosis. Rhonchi usually clear after coughing.

Stridor is a high-pitched musical sound heard on inspiration, which resembles wheezing. When listening with a stethoscope, if the sound is louder over the throat, it is Stryder, not wheezing. Air is moving roughly over a partially obstructed upper airway. Stridor is caused by something blocking the larynx, such as a person choking on an object.

Stridor can also be heard in a person with an infection, swelling in the throat, or laryngospasm. You may frequently hear stridor in children, as they are more likely to choke and more likely to get childhood infections like croup. Stridor can indicate a medical emergency if not enough oxygen is able to get through the airways. Listen to the sound of Stridor.

Previously termed rales, crackles are sounds that are heard in the lung field that has fluid in a small airways. Crackles can be heard on inspiration and expiration. Early inspiratory and expiratory crackles are heard in chronic bronchitis. Late inspiratory crackles may indicate pneumonia, CHF, or atelectasis, a complete or partial collapse of a lung or lobe of a lung.

They are broken down into fine crackles and coarse crackles. Fine crackles are high-pitched, brief, discontinuous popping lung sounds. Fine crackles sound like wood burning in a fireplace or cellophane being crumpled. Fine crackles usually start at the base of the lungs where there is fluid in the lungs. As the fluid fills the lungs more, fine crackles can be heard closer and closer to the top of the lungs.

Coarse crackles sound like coarse, rattling, crackling sounds that are louder, longer, and lower in pitch than fine crackles. They are described as a bubbling sound, as when pouring water out of a bottle or like ripping open Velcro. Coarse crackles are often heard just in certain spots in the lungs, possibly only on one side or in different spots on both sides.

They are usually caused by mucus in the bronchi. Listen to the sound of course crackles in a patient with pneumonia. Pleural rubs occur when two inflamed pleural surfaces rub against each other during respiration. This is often heard in pleurisy, or inflammation of the tissues that lie in the lungs and chest cavity. The sound may be continuous or broken and creaking or grating.

It can be described as the sound of walking on fresh snow or rubbing leather together. The sound of pleural rubs occurs every time the patient inhales and exhales. Pleural rubs come and go, are not altered with coughing, can usually be localized to a specific location on the chest wall, and will stop when the patient holds their breath.

Remember, if there is a loss of breath sounds in an area, it probably indicates a pneumothorax, or a collapsed lung, in which there is no air movement in that area. Let’s go over a quick review. Wheezing is a musical noise during inspiration or expiration, usually louder during expiration, and continuous. Rhonchi resemble low-pitched wheezes.

They are rumbling, coarse sounds like a snore during inspiration or exploration and continuous. It may clear with coughing. Stridor is a high-pitched musical sound heard on inspiration resembling wheezing. However, the sound is louder over the throat due to a partially obstructed airway.

Crackles are high-pitched discontinuous sounds during inspiration not cleared by a cough and further defined as fine and coarse. Pleural friction rub occurs during inhalation and exhalation, may be continuous or broken and creaking or grating. They stop when the patient holds their breath. Thank you for watching this video on lung sounds. For other useful tips, check out our other videos.

Breath Sound Assessment 

Normal breath sounds

Normal breath sounds can be further divided into two subcategories: vesicular and tracheal. Vesicular breath sounds are the sounds heard during auscultation of the chest of a healthy person (listen to the audio recording below). The inspiratory component predominates and is generated by turbulent airflow within the lobar and segmental bronchi, whereas the expiratory component is due to flow within the larger airways.

Vesicular breath sounds (MP3) Audio courtesy of MEDiscuss.

Tracheal sounds are the sounds heard over the sternum. They are louder and higher-pitched than vesicular sounds are. With tracheal sounds, the expiratory phase is as long as or longer than the inspiratory phase.

Abnormal (adventitious) breath sounds


A wheeze is defined as a continuous musical sound lasting longer than 250 ms (listen to the audio recording below). It is thought to be due to oscillation of opposing airway walls that are narrowed almost to the point of contact. A wheeze may be either expiratory or inspiratory and may contain either a single note or multiple notes. Wheezing is common, estimated to occur in 25% of the population at some point. It is frequently more audible at the trachea than in the chest.

Wheeze (MP3) Audio courtesy of MEDiscuss.

Clinically, wheezing indicates airflow obstruction, though its absence does not exclude obstruction. Such obstruction may occur at any point along the airway. Conditions associated with wheezing include the following:

  • Infection ( croup, whooping cough, bronchiolitis)
  • Laryngeal or tracheal tumors
  • Tracheal stenosis
  • Tracheomalacia
  • Foreign body aspiration
  • Other causes of large airway compression or stenosis
  • Vocal cord dysfunction
  • Asthma
  • Chronic obstructive pulmonary disease (COPD),
  • Cystic fibrosis
  • Bronchiectasis
  • Hypersensitivity pneumonitis
  • Pulmonary edema

A wheeze may be detected during forced expiration in normal subjects. Although wheezing is associated with airflow obstruction, the degree of obstruction cannot be reliably predicted by the presence or absence of wheezing. Generally, a polyphonic wheeze (ie, a wheeze with multiple notes) is characteristic of large airway obstruction, whereas a monophonic wheeze is more typical of small airway obstruction.

A study by Kevat et al found that the use of digital stethoscopes was superior to standard auscultation for detecting wheeze in children.


A squawk is defined as a very short wheeze. It is thought to occur when a closed airway suddenly opens during inspiration and the airway walls briefly remain in light contact. Squawks are most common in fibrotic disorders, particularly hypersensitivity pneumonitis.


Crackles are defined as a short, explosive, nonmusical sound (listen to the audio recording below). They can be divided into two types: fine and coarse. Compared with coarse crackles, fine crackles have a higher frequency and a shorter duration. Fine crackles are caused by the sudden opening of a closed airway; coarse crackles are thought to be related to secretions.

Crackles (MP3) Audio courtesy of MEDiscuss.

Crackles may occur on either inspiration or expiration but are more common during inspiration. Inspiratory crackles may be classified as early inspiratory, midinspiratory, or late inspiratory. Crackles are more frequently heard in the basilar regions of the lungs because the distribution of airway closure is gravity-dependent.

The number of crackles has been shown to correlate with disease severity. Crackles may be heard in cardiac disease, fibrotic lung disease, obstructive lung disease, and pulmonary infections. They may also be heard in healthy older individuals.

General characteristics of these crackles have been described for many different disorders (though there may be variations among individual patients). In idiopathic pulmonary fibrosis, crackles have been described as fine, short in duration, higher-pitched, and occurring in late inspiration. A basilar predominance exists in early disease.

Asbestosis is associated with fine crackles. The presence of crackles has been shown to be associated with honeycombing on imaging and with the duration of dust exposure. In bronchiectasis, crackles have been described as high-frequency and coarse. They occur in early inspiration or midinspiration and are thought to be secondary to bronchial wall collapse during expiration and sudden opening in inspiration.

In COPD, crackles are most commonly due to airway secretions and typically disappear after coughing; they may also be due to the opening and closing of narrowed bronchi with weakened airway walls. Crackles in COPD are characterized as coarse, early, and low pitched and tend to be infrequent.

The crackles associated with pulmonary edema are attributed to the opening of airways narrowed by peribronchial edema. They are described as coarse, late-occurring, and high-pitched. They may be inspiratory or expiratory.

In pneumonia, two types of crackles have been described. Early pneumonia is associated with coarse, midinspiratory crackles; crackles during the recovery phase are described as shorter and occurring at the end of expiration.

Crackles are relatively rare with sarcoidosis (because of the upper-lobe predominance of the disease); when they do occur, they are described as fine and either late inspiratory or midinspiratory.


Rhonchi are defined as low-pitched continuous sounds that have a tonal, sonorous quality. They are caused by the rupture of fluid films and airway wall vibrations and are associated with disorders that cause increased airway secretion or reduced clearance of secretions. Rhonchi tend to clear with coughing.


Stridor is defined as a high-pitched continuous sound heard over the trachea. It is due to turbulent flow generated in the upper airway during extrathoracic airway obstruction, and it tends to occur when the upper airway is narrowed to 5 mm or less. Stridor is louder than wheezing, and it is longer in inspiration than in expiration. It may be caused by any condition that leads to narrowing of the extrathoracic airway.

Other abnormal sounds

Pulmonary parenchymal consolidation may cause several changes in the quality of breath sounds. Bronchial breath sounds are breath sounds that are overly well transmitted to the chest wall as a consequence of increased sound transmission through the consolidated lung parenchyma (listen to the audio recordings below). These sounds are described as similar to tracheal sounds and are loud, high-pitched, tubular, and whistling. Expiration is as loud as, or louder than, inspiration.

Bronchial breath sounds (MP3) Audio courtesy of MEDiscuss.

Bronchovesicular breath sounds (MP3) Audio courtesy of MEDiscuss.

Consolidation also leads to changes in voice-generated sounds. Normally, the spoken voice has a muffled, indistinct quality when heard during auscultation of the chest. With a consolidated lung, the voice may take on a high-pitched, bleating quality (egophony) or may exhibit increased pitch or transmission of words (bronchophony or pectoriloquy). The so-called E-to-A sign has also been described, in which a spoken “E” sounds like “A” on auscultation of the abnormal area.

Several conditions are associated with a decrease in or absence of normal breath sounds. Diffusely decreased breath sounds may be noted in conditions that alter the transmission of sound through the chest wall (eg, obesity), as well as in obstructive lung disease. A focal decrease or absence in breath sounds may be due to pleural effusion, pneumothorax, or atelectasis.

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