Unusual cause of thigh abscess in infant following hepatitis B vaccine administration

A 30 days old healthy male infant with left thigh swelling was presented to our clinic by his family. parents gave no history of diseases or trauma and was administered hepatitis b vaccine from left thigh one week before. physical exam revealed approximately 3x2 cm, erythematous, indurated, tender to palpation, fluctuating soft tissue swelling over the anterolateral left thigh. during needle puncture, 15 cc purulent liquid was aspirated. as the liquid was purulent, irrigation and debridement were performed. following six weeks of antibiotic treatment, the patient was completely recovered.