Spontaneous subcutaneous emphysema following Influenza A virus infection in a young man: A case report

Spontaneous subcutaneous emphysema (SSE) is an uncommon condition characterised by the presence of air within the subcutaneous tissues in the absence of trauma or surgical intervention. It usually results from alveolar rupture due to elevated intra-alveolar pressure. We report a previously healthy 16-year-old man who presented with fever, cough, and sudden-onset diffuse chest pain during an influenza-like illness. Clinical examination revealed palpable crepitus over the neck and upper chest. Chest radiography and contrast-enhanced computed tomography demonstrated extensive cervical and thoracic subcutaneous emphysema, associated with a pneumomediastinum, in the absence of an underlying structural lung disease. Reverse transcriptase polymerase chain reaction (RT-PCR) testing of a throat swab confirmed Influenza A H1N1 infection. The patient was treated conservatively with oseltamivir, supplemental oxygen, analgesia, and close observation, resulting in complete clinical and radiological resolution within seven days.
This case highlights a rare manifestation of Influenza A infection in an adolescent. Severe coughing associated with influenza may markedly increase intra-alveolar pressure and precipitate alveolar rupture leading to pneumomediastinum and SSE. Although usually self-limiting, SSE may occasionally progress to serious complications including tension pneumothorax and airway compromise. Early recognition and appropriate imaging are therefore important for excluding life-threatening complications and guiding conservative management.