What is subcutaneous gas in the neck?

September 29, 2025 •

4 min read

Subcutaneous emphysema, the medical term for subcutaneous gas in the neck, occurs when air or gas becomes trapped beneath the skin. While sometimes benign and self-resolving, it can also signal a serious underlying medical issue such as trauma or infection, requiring prompt medical attention.

Quick Summary

Subcutaneous gas in the neck, or cervical subcutaneous emphysema, is a condition where air or gas accumulates in the soft tissues under the skin of the neck. It is most often caused by trauma, certain medical procedures, or infections that create a pathway for air to leak from the respiratory or gastrointestinal tracts.

Key Points

Definition: Subcutaneous gas in the neck, or subcutaneous emphysema, is when air or gas becomes trapped beneath the skin's surface.
Primary Sign: The most recognizable symptom is crepitus, a crackling or crunching sensation when the affected skin is touched.
Common Causes: Trauma (e.g., collapsed lung), certain medical procedures (e.g., intubation), and forceful actions like coughing or vomiting can lead to this condition.
Medical Emergency: While mild cases may resolve on their own, the underlying cause can be serious, and a medical evaluation is crucial.
Diagnosis: A physical exam combined with imaging techniques like X-rays or CT scans is used to confirm the diagnosis and find the source of the air leak.
Treatment Focus: Management focuses on treating the root cause, which can range from observation for mild cases to more involved procedures for severe ones.

Understanding the mechanics of subcutaneous emphysema

Subcutaneous emphysema, often simply called subcutaneous gas, is the presence of air or other gas in the subcutaneous layer of the skin. This can happen anywhere on the body but is most commonly found in the chest, face, and neck because of the connections between the fascial planes. A defining clinical sign of this condition is crepitus, which is a crackling or crunching sensation that can be felt and sometimes heard when the affected area is pressed.

Unlike emphysema of the lungs, this condition relates to trapped air in the skin's tissues rather than damage to the lungs' air sacs. While minor cases may resolve on their own, the condition's presence necessitates a thorough investigation to identify and treat the underlying cause, which can sometimes be life-threatening.

Common causes of subcutaneous gas in the neck

Subcutaneous gas can originate from various sources, indicating a disruption somewhere within the body's pressure systems. Trauma is a frequent culprit, but medical procedures and other conditions can also be responsible.

Trauma-related causes

Blunt or penetrating trauma: Injuries to the chest, neck, or face from accidents or stab wounds can cause air to leak from the lungs, trachea, or esophagus into the surrounding soft tissues.
Collapsed lung (Pneumothorax): A collapsed lung, which can occur with or without a rib fracture, can cause air to escape from the lung and travel up through the fascial planes to the neck and chest.
Increased intrathoracic pressure: Sudden, forceful increases in pressure within the chest cavity can rupture small air sacs in the lungs. This can be caused by strenuous coughing, forceful vomiting (as in Boerhaave syndrome), or even intense exercise.

Medical procedure-related causes

Intubation and ventilation: Placement of a breathing tube (endotracheal intubation) or use of a mechanical ventilator can sometimes lead to an air leak, especially if there is a complication.
Endoscopy or bronchoscopy: These procedures involve inserting a scope into the throat and respiratory or digestive tracts. Accidental perforation during these procedures can cause air to enter the tissues.
Dental procedures: High-pressure air or water used during certain dental extractions can sometimes force air into the surrounding tissues.

Infections and other rare causes

Necrotizing infections: Certain bacterial infections, such as gas gangrene, produce gas as a byproduct. This gas can accumulate in the subcutaneous tissue, leading to emphysema.
Spontaneous occurrence: In rare instances, subcutaneous emphysema can appear spontaneously without a clear cause, though it is often linked to increased intrathoracic pressure.

Diagnosing subcutaneous gas in the neck

Diagnosing subcutaneous emphysema involves a combination of a physical examination and medical imaging to confirm the presence of gas and identify its source. The characteristic symptom of crepitus is often the first sign that leads a doctor to investigate further.

Physical Examination: A healthcare provider will feel the affected area for swelling and the distinctive crackling sound or sensation. They will also assess for other symptoms like difficulty breathing or swallowing.
Medical Imaging:
- X-ray: A chest or neck X-ray can often reveal air trapped in the subcutaneous tissues.
- CT Scan: A computed tomography (CT) scan provides a more detailed image, pinpointing the exact location of the gas and helping to identify the underlying source of the air leak.
- Ultrasound: An ultrasound can be used to rule out a collapsed lung (pneumothorax) as a potential cause.
Endoscopy or Bronchoscopy: If the emphysema is suspected to be from a recent procedure or issue with the airway/esophagus, a scope may be used to visually inspect for damage.

Treatment approaches and management

Treatment for subcutaneous gas in the neck focuses on resolving the underlying cause. In many cases, especially mild ones, the air is naturally reabsorbed by the body over a period of days or weeks. However, severe cases or those with serious underlying conditions require more aggressive intervention.

Conservative management: Mild cases are often monitored closely while providing supportive care. This may include supplemental oxygen to help the body reabsorb the trapped gas faster.
Addressing the underlying cause: The primary focus is treating the root problem. This could involve surgery to repair a ruptured airway or esophagus, or administering antibiotics for an infection.
Releasing trapped air: For severe cases with extensive swelling that could compromise the airway, medical professionals may make small incisions in the skin (fenestrations) or use needles and catheters to decompress the area and release the trapped air.

The difference between subcutaneous emphysema and pneumomediastinum

While related and often co-occurring, it is important to understand the distinction between these conditions. For more detailed information on thoracic injuries and conditions, consider reviewing resources from authoritative medical institutions like MedlinePlus on Subcutaneous Emphysema.


Feature	Subcutaneous Emphysema	Pneumomediastinum
Definition	Air trapped in the soft tissues under the skin.	Air trapped in the mediastinum (the space in the chest between the lungs).
Location	Can occur anywhere, but commonly seen in the neck, face, and chest.	Confined to the chest cavity around the heart and other major organs.
Key Symptom	Crepitus, a crackling sensation on palpation of the skin.	Hamman's sign, a crunching or clicking sound heard with a stethoscope during heartbeats.
Origin	Air leaks from the mediastinum, lungs, or other structures into the fascial planes.	Usually results from increased intrathoracic pressure causing alveolar rupture.
Complications	Severe swelling can compress the airway and cause breathing difficulties.	Can compress mediastinal structures, including the heart, in severe cases.

Conclusion

Subcutaneous gas in the neck is a sign that air has escaped its normal pathways and is trapped under the skin. Its presence warrants prompt medical evaluation to determine the underlying cause and ensure no serious complications arise. While mild cases may resolve with minimal intervention, identification of the root problem is key to preventing more serious issues. Always consult a healthcare professional if you experience symptoms like neck swelling with a crackling sensation.

Frequently Asked Questions

Not always, but it is a potential sign of a serious underlying issue, such as trauma or infection. A medical evaluation is necessary to determine the cause and rule out life-threatening complications, especially if accompanied by difficulty breathing or swelling.

The most definitive sign is crepitus, which is the unusual crackling or crunching sensation felt when you press on the swollen skin. This is caused by the movement of air bubbles through the tissue.

Yes, both blunt and penetrating trauma to the neck, chest, or face are common causes. An injury can create a path for air to escape from the respiratory tract (like the trachea) or other structures and become trapped under the skin.

Yes, it can happen after certain medical procedures, especially those involving the airway or chest. Examples include endotracheal intubation, bronchoscopy, or even some dental procedures that use high-pressure air.

Treatment varies depending on the severity and underlying cause. Mild cases may only require observation and supplemental oxygen. More severe cases might require surgery to repair a leak or procedures to release the trapped air.

Pneumomediastinum is air in the chest cavity surrounding the heart, while subcutaneous emphysema is air in the skin's tissues. They often occur together, as air from the mediastinum can travel to the neck and face.

In most cases, once the underlying cause is addressed, the trapped air will be naturally reabsorbed by the body. This process typically takes about 10 days, though the duration can vary.