What is Subcutaneous Emphysema Vector

What is Subcutaneous Emphysema? (2024)

by | Updated: Apr 28, 2024

Subcutaneous emphysema is a medical condition characterized by the abnormal accumulation of air beneath the skin.

While it may sound unusual, subcutaneous emphysema can be a symptom of various underlying medical issues, ranging from minor injuries to serious medical emergencies.

In this article, we will explore the causes, symptoms, diagnosis, and treatment options for subcutaneous emphysema, shedding light on this uncommon but important medical condition.

What is Subcutaneous Emphysema?

Subcutaneous emphysema is a medical condition where gas or air is trapped under the skin. This typically occurs due to injury or infection, causing air to escape into the subcutaneous layer. It can result from chest trauma, lung disease, or medical procedures and is identified by a characteristic crackling sensation when touched.

Subcutaneous Emphysema Vector Illustration


Subcutaneous emphysema can be caused by a variety of factors, generally related to the escape of air from the respiratory system into the subcutaneous tissue.

Common causes include:

  • Trauma: Blunt or penetrating injuries to the chest or neck can tear the respiratory tract or esophagus, allowing air to leak into surrounding tissues.
  • Medical Procedures: Certain medical interventions, like mechanical ventilation, tracheostomy, or thoracic surgery, can inadvertently introduce air into subcutaneous tissues.
  • Lung Diseases: Conditions like severe asthma, COPD, or pneumothorax (collapsed lung) can cause air blisters (blebs) on the lungs to rupture, releasing air.
  • Infection: Severe infections, particularly those involving gas-producing bacteria, can lead to the formation of gas in tissues.
  • Esophageal Rupture: Spontaneous or trauma-induced rupture of the esophagus, such as in Boerhaave syndrome, can cause air to escape into subcutaneous tissues.
  • Diving Accidents: Scuba divers can experience this condition due to rapid changes in pressure, leading to lung barotrauma.

Note: These causes result in air escaping from the lung or gastrointestinal tract into the chest cavity and then moving into the subcutaneous layer of the skin. The condition is often accompanied by a distinctive crackling sensation (crepitus) when the area is palpated.


Subcutaneous emphysema presents with various symptoms, primarily related to the presence of air under the skin.

Key symptoms include:

  • Crepitus: The most distinctive symptom where the skin feels crackly or crunchy to touch due to air bubbles under the skin.
  • Swelling and Distension: Affected areas, usually around the neck, chest, face, or limbs, may appear swollen or distended.
  • Pain and Discomfort: Depending on the severity, there can be mild to severe pain or discomfort in the affected area.
  • Change in Voice: If the neck or throat is involved, there may be changes in voice or difficulty speaking.
  • Respiratory Symptoms: Difficulty breathing, shortness of breath, or a feeling of tightness in the chest, especially if the emphysema is associated with lung injury or disease.
  • Visible Changes in Skin: The skin over the affected area may appear stretched and shiny.
  • Facial Changes: In severe cases, puffiness around the eyes or face may occur.

Note: The severity and range of symptoms can vary greatly depending on the underlying cause and extent of the emphysema. In cases where lung function is compromised, or if the condition is a result of a serious underlying issue like a lung rupture or severe infection, immediate medical attention is necessary.


Diagnosing subcutaneous emphysema typically involves a combination of clinical assessment and imaging studies:

  • Clinical Examination: The distinctive feature of crepitus, a crackling sensation felt under the skin, is often the first clue. Physicians will also look for signs of swelling, pain, and changes in the skin over the affected area.
  • Medical History: Understanding the patient’s recent medical history, especially any recent surgeries, chest injuries, or respiratory problems, helps in making a diagnosis.
  • Imaging Tests: A chest x-ray is often the first imaging test performed. It can show air in the subcutaneous tissue, as well as any underlying lung conditions like pneumothorax. A computed tomography (CT) scan provides a more detailed image, showing the precise location and extent of the trapped air, and can also help identify underlying causes.
  • Other Investigations: In some cases, further tests might be needed to ascertain the cause of the air leak. This could include bronchoscopy, especially if a lung injury is suspected, or esophagography if an esophageal rupture is a possibility.

Note: The diagnosis is not solely based on imaging; it must correlate with the patient’s symptoms and medical history for accurate assessment. Prompt diagnosis is crucial, especially since subcutaneous emphysema can be a sign of more serious underlying conditions.


Treatment for subcutaneous emphysema focuses on managing the underlying cause and relieving symptoms.

The approach varies depending on the severity and origin of the condition:

  • Addressing the Underlying Cause: For lung-related issues like a pneumothorax, treatments may include chest tube insertion to relieve air pressure. If caused by a medical procedure, adjusting or correcting the procedure can help. In cases of infection, antibiotics or surgical debridement might be necessary.
  • Symptomatic Relief: Pain relief through analgesics. Monitoring and support for respiratory function, including supplemental oxygen if needed.
  • Observation and Monitoring: In mild cases, subcutaneous emphysema can resolve on its own, so monitoring and supportive care may be all that’s needed.
  • Surgical Intervention: Rarely, if the emphysema is extensive and not resolving, surgical intervention to release trapped air may be required.
  • Prevention of Recurrence: Addressing risk factors and careful management of lung diseases or conditions that predispose to air leaks.

Note: The treatment plan is tailored to each patient, considering the extent of the emphysema and the patient’s overall health. Close monitoring is essential to ensure that the condition is resolving and not leading to complications.

FAQs About Subcutaneous Emphysema

What is Emphysema?

Emphysema is a chronic lung condition, part of chronic obstructive pulmonary disease (COPD), characterized by the destruction of the air sacs (alveoli) in the lungs.

It leads to breathing difficulties due to reduced elasticity of the lung tissue, causing shortness of breath, and reduced oxygen exchange.

What is the Difference Between Emphysema and Subcutaneous Emphysema?

The key difference lies in their location and cause. Emphysema refers to a lung condition where air sacs are damaged, typically due to smoking or long-term exposure to airborne irritants.

Subcutaneous emphysema, on the other hand, involves air trapped under the skin, often due to injury or medical procedures.

While emphysema affects lung function, subcutaneous emphysema affects the skin and surrounding tissues.

What is Crepitus?

Crepitus refers to the crackling, crunchy sound or sensation under the skin, typically felt when palpating the area affected by subcutaneous emphysema.

It occurs due to gas or air trapped in the subcutaneous tissue.

Crepitus is also used to describe sounds from joints in conditions like arthritis, but in the context of emphysema, it specifically relates to subcutaneous air.

What Does Subcutaneous Emphysema Sound Like?

Subcutaneous emphysema itself does not produce a sound that is audible without medical equipment.

The characteristic feature is a tactile sensation known as crepitus, which feels like a crackling or popping sensation under the skin when palpated.

It’s not typically something you’d hear, but rather something a doctor might feel during a physical examination.

How Serious is Subcutaneous Emphysema?

The seriousness of subcutaneous emphysema largely depends on its cause and extent. Mild cases, often resulting from minor injuries or procedures, may resolve spontaneously with minimal treatment.

However, if it’s associated with significant underlying conditions like a pneumothorax, major trauma, or severe infection, it can be more serious and require immediate medical attention.

In such cases, it can be a sign of a life-threatening situation needing urgent intervention.

What are the Other Types of Emphysema?

Besides subcutaneous emphysema, there are several types of pulmonary emphysema, each with distinct characteristics:

  • Bullous Emphysema: This type is characterized by the formation of large air spaces, or bullae, in the lungs, typically in the upper lobes. These bullae can sometimes grow large enough to compress surrounding lung tissue, affecting lung function.
  • Paraseptal Emphysema: Occurring along the edges of the lungs near the pleura, paraseptal emphysema involves the distal airway structures, alveolar ducts, and alveolar sacs. It’s often associated with the formation of subpleural blebs, which can lead to spontaneous pneumothorax.
  • Panlobular Emphysema: This type involves uniform destruction of the entire alveolar unit (lobules) within the lung, most commonly seen in patients with Alpha-1 Antitrypsin Deficiency. It typically affects the lower lobes of the lungs and is more evenly distributed than other types.

Final Thoughts

Subcutaneous emphysema is a condition that warrants attention and understanding, as it can be a sign of underlying health concerns.

Prompt diagnosis and appropriate treatment are essential to address the root causes and alleviate the symptoms associated with this condition.

Whether it results from a simple injury or a more complex medical condition, respiratory therapists and other healthcare professionals play a crucial role in managing subcutaneous emphysema and ensuring the well-being of individuals affected by it.

Increased awareness and knowledge about subcutaneous emphysema can lead to better outcomes for patients and improved healthcare practices.

John Landry, BS, RRT

Written by:

John Landry, BS, RRT

John Landry is a registered respiratory therapist from Memphis, TN, and has a bachelor's degree in kinesiology. He enjoys using evidence-based research to help others breathe easier and live a healthier life.


  • Faarc, Kacmarek Robert PhD Rrt, et al. Egan’s Fundamentals of Respiratory Care. 12th ed., Mosby, 2020.
  • Kukuruza K, Aboeed A. Subcutaneous Emphysema. [Updated 2023 Jul 17]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023.

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