Subcutaneous emphysema is when air or gas gets under your skin tissue. Although this condition commonly occurs in the tissue of the neck or chest wall, it can develop in other body parts. A smooth bulging will appear on the skin.

Despite the name, subcutaneous emphysema is not a lung condition. It isn’t similar to subtypes of emphysema like bullous or paraseptal emphysema, which do affect the lungs.

Subcutaneous emphysema can occur when gas or air is trapped underneath the skin. It may appear as a complication of chronic obstructive pulmonary disease (COPD) or as a result of physical trauma to the lungs.

Subcutaneous emphysema is a rare condition that can occur after surgery of the thorax. However, many other factors contribute to disease development, including a collapsed lung and blunt trauma.

Many of the symptoms of subcutaneous emphysema differ from most other types of emphysema.

Symptoms of subcutaneous emphysema include:

  • sore throat
  • neck pain
  • swelling of the chest and neck
  • difficulty breathing, swallowing, or speaking
  • wheezing

Unlike other forms of emphysema, subcutaneous emphysema typically isn’t caused by smoking.

The main causes include:

  • certain medical procedures, including thoracic surgery, endoscopy, and bronchoscopy
  • coughing or sneezing while your glottis (the gap between your throat and your windpipe) is closed
  • collapsed lung accompanied by a rib fracture
  • facial bone fracture
  • ruptured esophagus or bronchial tube

You may also be at risk of subcutaneous emphysema if you have:

  • certain injuries, such as blunt trauma, stabbing, or a gunshot wound
  • certain medical conditions, including whooping cough or forceful vomiting
  • snorted cocaine or breathed in cocaine dust
  • had your esophagus damaged by corrosives or chemical burns

If you’re experiencing symptoms of subcutaneous emphysema, go to the emergency room.

During your appointment, your doctor will perform a routine physical exam and assess your symptoms. Before performing additional testing, your doctor will touch your skin to see if it produces an unusual crackling sound. This sound may be the result of gas bubbles being pressed through the tissues.

Your doctor may also order X-rays of your chest and abdomen to look for air bubbles and assess lung function.

Treatment will depend on the exact cause. Once the underlying causes are addressed, subcutaneous emphysema is likely to resolve in about 10 days.

In cases of severe subcutaneous emphysema in which pressure may damage your cardiovascular or respiratory systems, a doctor may recommend more invasive procedures.

Unlike most other forms of emphysema, subcutaneous emphysema itself is typically a benign condition. In most cases, your body will simply absorb the air trapped in the subcutaneous tissues.

But in some cases, gas may build up rapidly and more severely. This may cause compartment syndrome, constricted airways, and death of tissue (necrosis) if left untreated.

Emphysema is often preventable. In many cases, the risks depend on lifestyle choices that you can avoid.

To help lower your risk, consider avoiding the following factors (if applicable):

  • smoking
  • cocaine
  • exposure to airborne toxins, such as charcoal dust

If emphysema runs in your family, have your doctor run tests to determine your genetic risk of developing the disease.

In the case of subcutaneous emphysema, try protecting yourself against avoidable injuries. Bullous and paraseptal emphysema typically aren’t caused by physical trauma.

If you’re undergoing certain medical procedures, make sure to speak with your doctor about your risk of developing the rare condition.