Children with HDM allergy suffer from perennial allergic rhinitis (PAR). The present pilot study evaluated nasal lavage with isotonic saline (0.9%) in 25 children (mean age 8.9 years; 13 males) with HDM-dependent PAR, assessing: nasal symptoms severity and parental perception of rhinitis control, sleep, and school performance. Nasal symptoms, rated by total symptom score, parental perception of PER control, sleep quality, and school performance, measured by visual analogue scale, were significantly improved by nasal lavage (p < 0.001) after treatment. The effects tended to persist also during the follow-up. In conclusion, the present pilot study provides the first evidence that nasal lavage with isotonic saline relieved the nasal symptoms of children with PAR and improved the parental perception of the disease.