An 18-year-old woman presented to the emergency department with chest pain, dyspnea, and dry cough for 1 day. Dry cough was the initial symptom accompanied with fever and malaise. Approximately 12 h before presentation, shortness of breath developed. Dyspnea rapidly progressed; at the time of presentation, she was in respiratory distress. The patient also complained of diffuse chest pain at presentation. Her medical history was significant for Lyme disease at age 8 years. She denied using illicit drugs. The patient also had no exposure to animals and had no risk factors for HIV infection. She reported smoking a few cigarettes a day for several weeks before presentation. She was not taking any medications. Occupational exposure and family histories were noncontributory.