An estimated prevalence of 3.6 per million has been reported by Dinwiddie and coworkers through a national survey of chronic ILD in immunocompetent children in the United Kingdom and Ireland over a three year period (1995) (1996) (1997) (1998) [1] . This prevalence is certainly under-estimated due to the lack of standardized definitions and the absence of organized reporting systems. From the limited published data composed mainly of case reports and small series, it seems that pediatric ILD occurs more frequently in the younger age and in boys [11] . In addition, nearly 10% of cases appear to be familial [12] .