Abstract
Background: Bacillus Calmette–Guérin(BCG) vaccination is routinely administered intradermally at birth to prevent severe forms of tuberculosis. Incorrect administration can lead to rare but serious local complications. Case presentation: We report a term neonate who inadvertently received intramuscular BCG injection in the right forearm. The infant presented on day 29th of life with fever, irritability, and right arm swelling, requiring NICU admission. Investigations revealed leukocytosis and markedly elevated inflammatory markers. Imaging confirmed an abscess, and incision and drainage with serial debridement were performed. Culture yielded Methicillin-resistant Staphylococcus aureus. Histopathology demonstrated suppurative inflammation with granulomatous features. The patient was managed with targeted intravenous antibiotics and repeated wound care, followed by split-thickness skin grafting due to significant tissue loss. Conclusion: Accidental intramuscular administration of BCG can result in severe local complications, including secondary bacterial infection and mixed inflammatory pathology. Early recognition, appropriate surgical management, and targeted antimicrobial therapy are essential. This case underscores the importance of adherence to proper vaccination techniques to prevent avoidable morbidity.