Crepitus · What Is It, Causes, How It’s Assessed, and More

Crepitus refers to the sound and sensation associated with subcutaneous emphysema, a condition in which air is trapped within the subcutaneous tissue of the skin. It’s characterized by the palpable or audible popping, crackling, grating, or crunching sensation that can occur when air is pushed through the soft tissue. Crepitus is not a disease but rather a symptom of an underlying condition. 

Crepitus can occur anywhere in the body but is most common in the chest area, over the lungs; as well as the joints, like the knees, shoulders, elbows, and neck.  

The causes of crepitus in the chest usually involve underlying conditions that affect the structure of the lungs and surrounding tissues, like a pneumothorax (i.e., collapsed lung) or a rupture or tear in the airway. Additionally, a rupture or tear in the esophagus can also lead to crepitus in the chest area. For instance, if a pneumothorax occurs secondary to penetrating trauma, air may be able to leak from the pleural space to the subcutaneous tissues, resulting in the sound and sensation of crepitus when palpating the chest area.  

Crepitus can also be caused by barotrauma from mechanical ventilation. Barotrauma refers to lung injury from excessive pressure that can happen from mechanical ventilation.  

Crepitus is a clinical diagnosis made using auscultation and palpation. When lightly palpating the area, crepitus can be felt and sometimes heard. You may also hear it when using a stethoscope to auscultate over the area. During auscultation, crepitus usually sounds like crackling, clicking, or popping sounds; and depending on the underlying cause may be subtle or more pronounced. For reference, it sounds similar to rolling hair between your fingers.  

Additionally, imaging tests such as a CT scan or MRI may be done to help identify the underlying cause and assess the severity of the condition.