The aim of the project is to evaluate whether therapy with leukotriene may be a valid therapeutic approach in children with adenotonsillar hypertrophy and with mild and moderate obstructive sleep apnea syndrome (OSAS) and to evaluate whether leukotriene is less, equally or more efficient than nasal steroid.

The aim of the project is to evaluate whether leukotriene is less, equally or more efficient than nasal steroid in children with adenotonsillar hypertrophy and with mild and moderate OSAS checking if leukotriene administrated for 24 weeks improves overnight oximetry, polysomnography and checking if leukotriene as anti-inflammatory of upper airway really reduces the tonsils and adenoids dimensions.

Inclusion Criteria:

• Diagnosis of mild (RDI 3- <5) or moderate obstructive apneas (RDI 5-8) by overnight polysomnographic evaluation with 4 channels EEG
• Adenotonsillar hypertrophy Friedman score's II-III-IV°

Exclusion Criteria:

• Neuromuscular, gastrointestinal, neurological diseases and syndromes of malformations
• Use of leukotrienes and/or nasal and oral steroids in the 4 weeks preceding the initial sleep study
• Acute upper respiratory tract infections
• Adenotonsillectomy