As is the case with AOM, sinusitis is usually preceded by an upper respiratory tract infection.
Clinical symptoms vary with the age of the child.
In very young infants, the only symptoms may be fever and irritability. In older children and adolescents, symptoms may be more localized to the sinuses and include rhinorrhea, headache, facial pain, and fever. The diagnosis is usually based on clinical history and physical findings, but cannot be made unless the symptoms have been present for over 10 days without clinical improvement.