Allergic rhinitis can cause enough inflammation to obstruct the openings to the sinuses. Consequently, a bacterial sinus infection occurs. The disease is similar for children and adults. Children may or may not complain of pain.
However, in acute sinusitis, they will often have pain and typically have fever and a purulent nasal discharge. In chronic sinusitis, pain and fever are not evident. Some children may have mood or behavior changes. Most will have a purulent, runny nose and nasal congestion even to the point where they must mouth breathe. The infected sinus drains around the Eustachian tube, and therefore many of the children will also have a middle ear infection.