5 Conditions That Cause a Crackling Sound When You Breathe

Healthy lungs are relatively quiet. So if you notice you or a loved one is making a crackling sound while breathing, it's important to find out what may be going on.

Crackles, sometimes called "rales" by pulmonologists, are a specific type of breathing sound linked to certain health problems.

"They're caused by the small airways or air sacs popping open," when someone breathes in, explains Sandeep Gupta, MD, a pulmonologist at Memorial Hermann in Houston, Texas. (Crackles are different from wheezing, which sounds more like a high-pitched, whistling sound.)

Crackly breathing occurs when the airways are filled with fluid or if they've become overly rigid (which mean the crackles can't be cleared by coughing), and it's usually a sign of a lung infection or disease, Dr. Gupta says. It often goes hand-in-hand with feeling short of breath.

Here's a closer look at the most common causes and how they should be treated. Plus, learn when to seek medical attention for chest crackling.

Pneumonia happens when the lungs become inflamed or fluid-filled because of a bacterial, viral or fungal infection (like the flu, COVID-19 or pneumococcal disease).

In addition to causing breathing to sound crackly, it can also make it harder to breathe and cause chest pain. A person with pneumonia might also have a high fever and cough up yellow, green or bloody mucus or spit, notes the Cleveland Clinic.

Anyone can develop pneumonia. But it's more common in people who are over 65 or under 2, have a heart or lung condition or have a weakened immune system.

Bronchiectasis is a chronic condition where the tubes that carry air in and out of the lungs become inflamed and damaged (usually from infections or damage done by certain conditions, such as cystic fibrosis or lupus), and it can cause crackly breathing, Dr. Gupta says.

Lungs affected by bronchiectasis aren't able to clear out mucus, which can cause coughing, trouble breathing and shortness of breath, according to the National Heart, Lung, and Blood Institute (NHLBI).

People with the condition may also start to develop thicker skin under their fingernails or toenails, which can cause the nails to curve downward.

People can develop bronchiectasis from an infection like pneumonia, whooping cough or measles. Having a condition like cystic fibrosis, HIV/AIDS or Crohn's disease can also raise a person's risk, the NHLBI says.

Pulmonary edema, or fluid buildup in the lungs, is marked by severe breathing difficulties, especially during activity or when lying down, coughing up frothy or blood-tinged mucus and rapid heartbeat.

It can also give a person's breathing a wet, crackly sound, which is caused by fluid moving through the airways, according to ScienceDirect. Over time, a person might also develop fatigue and swelling in the legs and feet.

Pulmonary edema is usually caused by a heart problem like heart failure or a heart valve problem. It can also affect people with kidney disease or thyroid conditions, per the Mayo Clinic. Having diabetes, high blood pressure or sleep apnea can also increase a person's risk.

In some instances, a person can develop pulmonary edema when they're at high altitudes, like if they're rapidly going up a mountain.

Chronic obstructive pulmonary disease, or COPD, is a long-term condition that can result in low-pitched crackles when a person breathes, notes the National Library of Medicine.

Often the result of smoking, COPD can cause a person to cough up mucus and experience shortness of breath and chest tightness or heaviness.

It gets worse over time and can make it harder for a person to perform their daily activities.

Interstitial lung disease (ILD) can cause the lungs to become scarred and stiff, leading to trouble breathing, a dry cough, chest discomfort and fatigue. It can also cause dry, crackly breathing "that mimics the separation of Velcro surfaces," Dr. Gupta says.

ILD can be the result of medical treatments like chemotherapy or radiation, or it may happen from exposure to hazardous materials like asbestos. Having an autoimmune disease like sarcoidosis or rheumatoid arthritis can also increase a person's risk, according to the American Lung Association (ALA).

If you notice a crackling sound when breathing, don't ignore it: The sound is usually a sign of a lung problem.

"Patients should seek medical attention if they have loud crackling sounds," Dr Gupta says.

Shortness of breath, coughing up blood and fever are other red flags to get medical help.