Milk Intolerance in Children With Persistent Sleeplessness: A Prospective Double-Blind Crossover Evaluation

From July 1986 to July 1988, 146 children less than 5 years of age were referred by their physicians to our university sleep clinic for continual waking and crying during sleep hours. For 85 children (58.2%), the sleeplessness was attributed to inappropriate sleep habits. For 17 children (11.6%), no explanation was found for the sleep difficulties in spite of an extensive workup. Their median age at referral was 13.5 months (range 2.5 to 29 months). Their persistent sleeplessness was tentatively attributed to an undiagnosed intolerance to cow's milk. Cow's milk was excluded from their diet. In 15 children sleep normalized after 5 weeks (range 4 to 6 weeks). As seen from the parents' logs, the median time needed by the children to fall asleep decreased from 15 minutes (range 15 to 60 minutes) to 10 minutes (range 10 to 15 minutes, P = .001). The number of complete arousals decreased from 5 (range 1 to 12) to less than 1 per night (range 0 to 2) (P = .001). Total sleep time per 24 hours increased from 5.5 hours (range 3 to 8.5 hours) to 13.0 hours (range 10 to 14.5 hours, P = .001). Sleep normalized in one child who continued to receive no cow's milk only after the hydrolyzed hypoallergenic diet was discontinued. In every child, a double-blind crossover challenge was conducted involving a control diet containing no cow's milk and a diet containing cow's milk. The challenge induced the reappearance of insomnia and agitated behavior in all except one child. The child's initial sleep difficulties were retrospectively attributed to inappropriate sleep habits. To confirm the need to maintain the exclusion diet, double-blind crossover challenges with cow's milk were repeated with 10 children. Challenges were done between 16 and 22 months of age in 7 children and between 25 and 57 months of age in 3 children. The types of reactions observed were comparable with those seen previously, with the exception of that seen with a 57-month-old girl. She showed no sleeplessness during the challenge and was allowed a normal diet. At 24 months of age (range 15 to 50 months), 14 children were still being treated with the exclusion diet. Occasional sleepless nights were observed following accidental reintroduction of cow's milk in the diet. The observation that most insomniac infants respond successfully to changes in sleep routine and to behavioral approaches is supported by this study. Only the most persistent cases, those not responding to other forms of treatment, should be considered potential candidates for the diagnosis of food intolerance. An exclusion diet, managed with competent medical supervision, could bring the family long awaited relief within a few weeks. The diagnosis can then be confirmed by a milk challenge test.