Crepitus; Subcutaneous air; Tissue emphysema
Subcutaneous emphysema occurs when air gets into tissues under the skin. This most often occurs in the skin covering the chest wall or neck, but can also occur in other parts of the body.
Subcutaneous emphysema can often be seen as a smooth bulging of the skin. When a health care provider feels (palpates) the skin, it produces an unusual crackling sensation (crepitus) as the gas is pushed through the tissue.
This is a rare condition. When it does occur, possible causes include:
- Collapsed lung (pneumothorax), often occurring with a rib fracture
- Facial bone fracture
- Ruptured bronchial tube
- Ruptured esophagus
This condition can happen due to:
- Blunt trauma.
- Blast injuries.
- Breathing in cocaine.
- Corrosives or chemical burns of the esophagus.
- Diving injuries.
- Forceful vomiting (Boerhaave syndrome).
- Gunshot wounds.
- Pertussis (whooping cough).
- Certain medical procedures that insert a tube into the body. These include endoscopy (tube into the esophagus and the stomach through the mouth), a central venous line (thin catheter into a vein close to the heart), endotracheal intubation (tube into the throat and trachea through the mouth or nose), and bronchoscopy (tube into the bronchial tubes through the mouth).
Air can also be found in between skin layers on the arms and legs or torso after certain infections, including gas gangrene, and after scuba diving. (Scuba divers with asthma are more likely to have this problem than other scuba divers.)
When to Contact a Medical Professional
Most of the conditions that cause subcutaneous emphysema are very severe, and you are likely already being treated by a provider. Sometimes a hospital stay is needed. This is more likely if the problem is due to an infection.
If you feel subcutaneous air in relation to any of the situations described above, particularly after trauma, call 911 or your local emergency services number immediately.
DO NOT administer any fluids. DO NOT move the person unless it is absolutely necessary to remove them from a hazardous environment. Protect the neck and back from further injury when doing so.
What to Expect at Your Office Visit
The provider will measure and monitor the person's vital signs, including:
- Breathing rate
- Blood pressure
Symptoms will be treated as needed. The person may receive:
- Breathing support, including oxygen, endotracheal intubation (tube through the nose or mouth into the trachea) and ventilator (breathing machine)
- Blood tests
- Chest tube -- tube through the skin and muscles between the ribs into the pleural space (space between the chest wall and the lung) if there is lung collapse
- CAT/CT scan (computerized axial tomography or advanced imaging) of the chest and abdomen or area with the subcutaneous air
- ECG (electrocardiogram or heart tracing)
- Fluids (intravenous or through the vein)
- Medicines to treat symptoms
- X-rays of chest and abdomen and other body parts that may have been injured
The prognosis depends on the cause of the subcutaneous emphysema. If associated with major trauma, a procedure or infection, the severity of those conditions will determine the outcome.
Subcutaneous emphysema associated with scuba diving is most often less serious.
Byyny RL, Shockley LW. Scuba diving and dysbarism. In: Walls RM, Hockberger RS, Gausche-Hill M, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 9th ed. Philadelphia, PA: Elsevier; 2018:chap 135.
Cheng G-S, Varghese TK, Park DR. Pneumomediastinum and mediastinitis. In: Broaddus VC, Mason RJ, Ernst JD, et al, eds. Murray and Nadel's Textbook of Respiratory Medicine. 6th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 84.
Raja AS. Thoracic trauma. In: Walls RM, Hockberger RS, Gausche-Hill M, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 9th ed. Philadelphia, PA: Elsevier; 2018:chap 38.
Kosowsky JM, Kimberly HH. Pleural disease. In: Walls RM, Hockberger RS, Gausche-Hill M, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 9th ed. Philadelphia, PA: Elsevier; 2018:chap 67.