免疫不全を伴わない3ヶ月乳児における急速進行性播種性BCG感染症（BCGitis）：症例報告

BACKGROUND Disseminated Bacillus Calmette-Guerin (BCG) disease is a rare but severe complication of BCG vaccination, particularly in immunocompromised children, and is associated with high mortality. The incidence of disseminated Bacillus Calmette-Guerin disease is approximately 1.56 to 4.29 cases per million vaccinated individuals, with an overall mortality of 60% to 80%. Lesions most commonly appear in the right arm, axilla, and areas adjacent to the injection site. We report a case of a rare presentation of disseminated BCGitis 3 months after the intradermal vaccine. CASE REPORT A previously healthy 3-month-old infant developed devastating skin, subcutaneous, bone, lymphatic, and systemic complications located in the head and neck. The rapidly progressive and destructive growth of the lesions simulated a malignant neoplasm. After several weeks of investigation and challenging diagnosis, the patient was successfully treated with a 7-month regimen of rifampicin, isoniazid, and ethambutol, with resolution and no sequelae. No underlying immunodeficiency was identified. At 3-year follow-up, the child demonstrated normal neurodevelopment and psychomotor function, with no significant infections or other immune-related problems. CONCLUSIONS Disseminated BCGitis can be the first manifestation of a primary immunodeficiency or secondary immunodeficiency or can occur sporadically, as in our patient. The condition can progress rapidly and be fatal, making early recognition essential.