Ulcerated Arm Lesion in a 10-day-old Girl

Presentation

A 10-day-old girl presents with a progressive right upper extremity skin lesion. She was born large for gestational age at term via cesarean delivery for fetal distress. Pregnancy was complicated by diet-controlled gestational diabetes and a maternal history of genital herpes. The mother received prophylactic valacyclovir and no active herpes lesions developed during pregnancy. Immediately after birth, the infant was noted to have a 2-cm, tender, well-circumscribed area of erythema and induration over the right antecubital fossa. The extremity also had decreased movement, diminished radial pulse, and weak grasp reflex. Otherwise, she was well-appearing and her examination was normal. Radiographs of the forearm and clavicle were negative for fracture. She was diagnosed with hematoma and possible brachial plexus injury and discharged from the nursery on postnatal day 3 with the arm immobilized in a sling and acetaminophen as needed for pain.

Since discharge from the nursery, the lesion has spread, ulcerated, and started draining malodorous white discharge, so the patient returns for evaluation on postnatal day 10. On physical examination, she has a poorly demarcated, erythematous, tender, indurated, circumferential plaque that extends from the mid-upper arm through the antecubital fossa to the mid-forearm. The center of the lesion is violaceous and ulcerated with white discharge (Fig 1). The affected extremity has decreased spontaneous movement, weak radial pulse, nearly absent grasp reflex, and she has pain with passive manipulation of the affected elbow. Her vital signs and the remainder of her physical examination are normal. Complete blood cell count with differential, procalcitonin, and c-reactive protein are within normal limits for age. Blood culture and herpes simplex virus polymerase chain reaction …