Three infants with a relapsing form of infant botulism are reported from the Division of Child Neurology, The Children’s Hospital of Philadelphia, PA. Between Jan 1, 1976 and Jan 1, 1989, 63 infants with confirmed infant botulism presented with the characteristic complaints of constipation followed by hypotonia, bulbar signs, and weakness. The diagnosis of infant botulism was confirmed by toxin identification in stool. The median age was 13.5 weeks (range 2-33 weeks of age) and the median length of hospitalization was four weeks. Three infants (5%) relapsed after a 1-2 week normal interval at home. None had been re-exposed to honey. Electrophysiological testing showed incremental response in compound motor action potential to high rates of repetitive stimulation. Recovery from relapse was complete but the authors recommend careful follow-up of infants after discharge. 
COMMENT. The mechanism underlying this relapse was unknown. Over 600 cases have been reported in the past 14 years and the disease is endemic in California, Utah, and Pennsylvania. Risk factors are breast-feeding and possibly honey. The differential diagnosis includes systemic infection, tic paralysis, myasthenia gravis, congenital myopathies, and myasthenic syndromes, Guillain-Barre syndrome, and organic phosphate intoxication. There is no specific treatment. Some antibiotics such as aminoglycosides may impair neuromuscular transmission and may exacerbate the paralysis and hypotonia.