Background <p>Hamman’s syndrome is a rare condition in children that presents with pneumomediastinum and subcutaneous emphysema caused by barotrauma. Even rarer is the occurrence of Hamman’s syndrome caused by esophageal firework-related injury, as seen in our case. Firework injuries vary depending on the location of the injury. Esophageal injury is rare. Conservative treatment is the preferred approach for managing these injuries.</p> Case presentation <p>A seven-year-old boy fired a small firework and immediately swallowed it. Subsequently, the patient developed noticeable facial, cervical, and upper chest swelling. The patient had been taken to another medical center before coming to us, where he received initial care for two days. Chest CT tomography revealed pneumomediastinum and subcutaneous emphysema, consistent with Hamman’s syndrome. Contrast esophagography revealed a posterior esophageal diverticulum without apparent leakage. In our emergency department, the patient’s vital signs were stable, and physical examination revealed soft tissue swelling. A new contrast esophagogram revealed a posterior esophageal diverticulum with a false passage extending approximately 12.5&#xa0;cm, but no extravasation of the contrast agent was observed. We decided to proceed with observation and stopped oral feeding for one month by creating an alternative feeding tract through a Stamm gastrostomy. Later, upper gastrointestinal endoscopy revealed remnants of a healed injury in the esophagus without stricture or edema, and oral re-feeding was gradually achieved.</p> Conclusion <p>Hamman’s syndrome may result from extremely rare causes, such as esophageal firework-related injury, and that can be serious. Esophageal firework-related injury itself also a rare case. Conservative treatment has good results.</p>