[Yellow nail syndrome: two pediatric case reports]

Yellow nail syndrome (YNS) is a combination of specific nail dystrophy (yellowish or green nails, transverse ridging, increased curvature with "a hump" and distal onycholysis), lymphoedema and respiratory tract involvement (mainly bronchial hyper-responsiveness, recurrent pneumonia, bronchiectasis and pleural effusion), with or without sinusitis. This rare condition is most often seen in middle age. We report two pediatric cases.

A 9-year-old boy had 20 yellow nails and lymphedema of the lower and upper left limbs. He was born at 32 weeks of gestation. At birth, he had fetal hydrops with bilateral chylothorax. Since then, he presented bronchopulmonary dysplasia. In his first year of life, he had recurrent nasopharyngitis and serosal otitis. Lymphoscintigraphy was not performed. A 14-year-old boy had 10 yellow toenails and 2 yellow fingernails. He was born at 36 weeks of gestation with fetal hydrops. He had recurrent serosal otitis and asthma attacks. Lymphoscintigraphy showed lymphatic hypoplasia, especially of the left limbs.

These two children have the classic triad of YNS, including yellow nails, lymphedema and respiratory tract involvement. Thirteen cases have been reported in children from birth to 10 years of age, three of whom were siblings, thus suggesting genetic predisposition. In most cases lymphoscintigraphy showed hypoplasia and/or ectasia of lymphatic vessels. These lymphatic abnormalities may be responsible for nail changes as seen in Turner's syndrome. The prognosis of YNS in adults may be serious because of the pulmonary tract involvement. However, it is not known in children.

Yellow dystrophic nails in children may be associated with lymphedema and respiratory tract involvement, as in adults, and this condition should therefore be investigated in cases of YNS.