The following report outlines the case of a 76-year-old gentleman who presented to the hospital with acute interstitial pneumonitis, a rare and rapidly progressive type of idiopathic interstitial pneumonia. The patient initially presented with a three-week history of progressive shortness of breath and cough which was diagnosed as community acquired pneumonia. Treatment with oral antibiotics was unsuccessful resulting in re-presentation the following week with type one respiratory failure. Investigations revealed widespread inflammatory changes consistent with an acute inflammatory process. Intravenous steroids, antibiotics and antiviral medications were initiated before an urgent transfer to the intensive care unit was required for intubation. An open lung biopsy, in conjunction with the clinical picture, confirmed the diagnosis of acute interstitial pneumonitis. The significance of this report is to highlight the rapid and destructive clinical course of a rare type of pneumonitis, which initially presented as a routine and innocuous diagnosis in our patient.