Background: Diffuse alveolar hemorrhage (DAH) is a potentially life-threatening condition that can occur due to a variety of disorders. Hence, rapid diagnosis and prompt initiation of appropriate treatment are imperative.Case: A 55-year-old woman with a deep neck infection underwent emergent tonsillectomy. General anesthesia and surgery proceeded uneventfully. Upon transfer to the post-anesthesia care unit, ongoing respiratory distress and occasional expectoration of blood-tinged sputum were noted. Lung ultrasonography (LUS) revealed multiple B-profiles and irregular pleural lines with subpleural consolidations. Emergent bronchoscopy with bronchoalveolar lavage was diagnostic of DAH. She underwent a comprehensive evaluation for rheumatologic and infectious etiologies of DAH, all of which yielded negative results. The patient was managed with steroids and conservative treatment. Conclusions The integration of LUS with clinical information allows for more rapid differentiation of acute respiratory failure causes. Therefore, anesthesiologists’ awareness and utilization of LUS findings of DAH can significantly contribute to appropriate management.