Background: We conducted a multicenter clinical survey to clarify the current attitudes to diagnosis or treatment of neonatal milk allergy (NMA) in institutions providing medical care for high-risk neonates in Japan.
Methods: Questionnaires were distributed to 263 institutions that provide medical care for high-risk infants. Information was requested on the number of hospitalized neonates between January 2004 and December 2005, the number of neonates diagnosed with milk allergy, frequent clinical symptoms, and clinical tests performed routinely when NMA was suspected.
Results: Responses were received from 145 institutions (55.1%). Of 69 796 hospitalized neonates, a diagnosis of cow's milk allergy was made in 0.21%. The incidence in infants with birthweight <1000 g was 0.35%. Gastrointestinal symptoms were identified as the most frequent symptoms that suggested NMA by 80% of institutions. A challenge test in each suspected case was performed in only 15% of institutions, even though it was considered to be the most significant test for diagnosis. Most institutions considered a specific immunoglobulin E test in cases of suspected NMA, but only one-third agreed on its diagnostic significance. A lymphocyte stimulation test was performed in only 5.5% of institutions.
Conclusions: This study is the first to show the incidence of NMA in institutions providing medical care for high-risk neonates in Japan. Current clinical tests may be insufficient for diagnosis of NMA in which non-immunoglobulin-E-mediated delayed allergic reactions are involved. Therefore, awareness of the clinical features of this disorder is required among neonatologists and allergists.