Erythema at the bacillus Calmette-Guerin scar after influenza vaccination

Abstract

A nine-year-old Mexican boy presented with pain, swelling, and redness at the BCG scar (Figure 1 A) two days after an influenza vaccination (administered 3 cm from the BCG scar). The BCG scar was erythematous, indurated, and painful, while the influenza vaccination site remained unchanged. Vital signs were normal, with no signs of lymphadenopathy. The patient had a previous history of severe local reaction after BCG vaccination at 3 months of age (ulcer formation and nonsuppurative axillary lymphadenopathy). Additionally, the patient was tested positive for a tuberculin skin test at 3 years of age and received isoniazid/rifampin treatment. Erythema and induration at the BCG scar lasted 48 h, resolving without topical or systemic treatments (Figure 1B).