Mondo Description Bronchiolitis obliterans organizing pneumonia (BOOP) is a lung disease that causes inflammation in the small air tubes (bronchioles) and air sacs (alveoli). BOOP typically develops in individuals between 40-60 years old; however the disorder may affect individuals of any age. The signs and symptoms of BOOP vary but often include shortness of breath, a dry cough, and fever. BOOP can be caused by viral infections, various drugs, and other medical conditions. If the cause is known, the condition is called secondary BOOP. In many cases, the underlying cause of BOOP is unknown. These cases are called idiopathic BOOP or cryptogenic organizing pneumonia. Treatment often includes corticosteroid medications.