Insomnia and cow's milk allergy in infants.

A group of eight infants (six boys and two girls, 7 to 46 weeks of age) is reported, in whom a causal relationship between cow's milk allergy and chronic sleeplessness was suspected. They were referred because of waking and crying episodes that had occurred since the early days of life during sleep hours. During an average night, they slept about 4.5 hours and woke their parents about five times. They cried a lot during the day and were described as fussy. Two infants had been treated with phenothiazine without improvement. No cause for chronic insomnia was found during a standard medical and psychologic workup. An all-night polygraphic recording confirmed the disrupted sleep pattern of these infants, as compared with that of normal infants, and excluded further causes of arousals. Due to a clinical suspicion of atopy, the infants were further subjected to a series of allergy tests. IgE levels were shown to be elevated in each child, and radioallergosorbent tests were positive for cow's milk protein. The infants were than fed exclusively with a hydrolyzed milk protein mixture for 4 weeks. Sleep normalized within 2 weeks in every infant: night sleep increased to a median of 10 hours, and the awakenings only occurred occasionally. In four infants less than 6 months of age, cow's milk was reintroduced in the diet, and within 1 week all four became severely sleepless. Cow's milk was again excluded from the diet and the babies' sleep behaviors were again normalized. It is concluded that, when no evident cause for sleeplessness can be found in an infant, the possibility of milk allergy should be given serious consideration.