Biphasic course of infant botulism.

The syndrome of infant botulism, characterized by constipation, poor feeding, hypotonia, poor head control, and bulbar involvement, is typically a monophasic disease. We describe a 7-month-old infant with a recurrence of illness 13 days after resolution of the presenting signs. The source of infection was unknown and the only potential risk factors were exclusive breastfeeding and decreased bowel movements, which by themselves cannot explain the recurrence. Although treatment with botulism immunoglobulin is now suggested for the acute phase of infantile botulism, its use for recurrence is controversial.