Pneumothorax is the presence of air in the pleural space and can be spontaneous, due to trauma, or iatrogenic. It is classified as primary spontaneous which occurs without lung disease usually in young males, secondary spontaneous which occurs with underlying lung pathology, or traumatic. Types include closed which seals off, open with a bronchopleural fistula, and tension which increases pressure. Clinical features include chest pain and shortness of breath. Diagnosis is made with chest x-ray showing increased radiolucency. Small primary pneumothoraces may resolve on their own while secondary pneumothoraces and those with symptoms require tube thoracostomy drainage. Recurrent cases require pleurodesis or surgery.