There is no single simple solution to the problems of nasal congestion and chronic catarrh in children with Down’s syndrome.
Basically the whole skeletal structure of the mid-face and of the throat area behind the mouth tends to be rather cramped so that drainage of normal mucous secretions is compromised. This leads to mucous pooling and stagnating in the nasal passageway and this provides a focus for infection. Once infection sets in yet more mucous is produced and a vicious circle results. As a general rule as children get older the situation improves as the airways behind the nose and mouth widen.
You will find some strategies for managing nasal congestion / catarrh in children in an article that was published in DSA Journal 125. Download here.