A pleural friction rub is a raspy breathing sound caused by inflammation of the tissues around your lungs. The sound is usually “grating” or “creaky.” It’s also been compared to the sound of walking on fresh snow.

Your pleura are two thin layers of tissue that separate your lungs from your chest cavity.

One of these pleura layers is tightly attached to your lungs, and the other is attached to the lining of your chest wall. There’s a small fluid-filled space between them known as the pleural cavity.

You may experience pain and a pleural friction rub when these two layers of tissue become inflamed or if they lose the lubrication between them. A pleural friction rub may be a symptom of a serious lung condition.

Keep reading to learn about the most common causes of a pleural friction rub, when you should talk to a healthcare provider, and the most common treatment options.

A pleural friction rub is almost always a sign of pleurisy.

Pleurisy, otherwise known as pleuritis, is another name for inflammation of the pleura tissues around your lungs. Conditions that lead to pleurisy may also cause a pleural friction rub.

Viral infections

Viral infections that target the lungs are the most common cause of pleurisy. Viral pleurisy often causes sharp chest pain when breathing.

Bacterial infections

Infections like bacterial pneumonia that target your lungs may lead to a pleural friction rub. Your healthcare provider may prescribe antibiotics to help your body fight against the condition.

Serositis

Serositis is an inflammation of the linings of your lungs, heart, and abdominal organs.

Autoimmune conditions like rheumatoid arthritis, inflammatory bowel disease, and juvenile idiopathic arthritis can lead to serositis. Kidney failure, infections, and AIDS are among other potential causes.

Pleural effusion

Pleural effusion is also known as “water on the lungs.” It’s a buildup of fluid between the layers of your pleural tissue.

Common causes of pleural effusion include:

Chest injuries

Injuries that affect your chest area, like broken ribs, can cause inflammation of your pleura and fluid buildup. Car collisions, assaults, and sports injuries are among potential causes of chest injuries.

A pleural friction rub may be a sign of a serious medical conditions. If you believe that you may have a pleural friction rub, it’s a good idea to promptly see a healthcare provider.

A pleural friction rub caused by pleurisy may be accompanied by sharp chest pain, shortness of breath, and a dry cough. Pain often gets worse when you cough or sneeze.

If your healthcare provider suspects that you may have a pleural friction rub, they’ll give you a series of tests to locate the inflamed part of your lung.

The following tests may help locate the cause of your pleural friction rub.

Blood tests

Blood tests can help your healthcare provider determine if you have an infection that’s causing your pleural friction rub.

A blood test may also help them diagnose an autoimmune disorder like rheumatoid arthritis, which might lead to pleurisy.

X-ray

A chest X-ray can help your healthcare provider pinpoint the location of inflammation. They may also take a decubitus chest X-ray, where you lie on your side. This type of X-ray can identify fluid buildup in your lungs.

CT scan

A computerized tomography scan (CT scan) can provide your healthcare provider with more information than an X-ray.

The machine generates cross-sectional images that can reveal if your pleura are damaged. CT scans can also create images of your soft tissue, bones, and blood vessels.

Ultrasound

An ultrasound uses high-frequency sound waves to identify potential areas of inflammation in your lungs. It may also be able to identify pleural effusion or fluid buildup.

Thoracentesis

Thoracentesis may be used to identify the reason for fluid buildup between your pleural layers.

During the test, your healthcare provider may use an ultrasound to find the area of fluid buildup. They will then insert a needle into your pleural cavity to drain fluid and test it for potential infection or inflammation.

Thoracentesis is an invasive test that’s rarely used if you have pleurisy alone, but it’s common when you have a pleural effusion and the cause is unknown.

The best treatment option for your pleural friction rub depends on the underlying cause.

Antibiotics

If the pleural friction rub is caused by a bacterial infection, your healthcare provider might prescribe antibiotics for the infection. Symptoms of pleurisy such as pleural friction rub usually improve within 2 weeks.

Nonsteroidal anti-inflammatory drugs

Your healthcare provider may recommend nonsteroidal anti-inflammatory drugs like ibuprofen to help manage inflammation. These drugs have a smaller chance of causing side effects than corticosteroids.

Chest tube

A chest tube may be used to drain fluid buildup from your pleural cavity. You may have to stay in the hospital for several days for this procedure.

Medication injection

If there’s a buildup of materials that can’t be drained, you may be administered medications to help break them up.

Surgery

In some cases, surgery may be the best option to remove fluid, parts of the pleura, or blood clots. If a pleural friction rub is caused by trauma, surgery may be necessary to help your injuries heal properly.

A pleural friction rub is a symptom that may be caused by a serious underlying condition.

If you believe you may have a pleural friction rub, it’s recommended that you see a healthcare provider as soon as possible to get a proper diagnosis.

Your healthcare provider will also be able to recommend the best treatment option based on the specific cause of your pleural friction rub.

Avoiding smoking, if you smoke, getting adequate rest, and taking the medication that your healthcare provider recommended may help you manage your symptoms.