Upper respiratory infections in children are the most common reason for visits to the pediatrician. Viruses are usually to blame for the few days of runny/stuffy nose, head fullness and irritability. When the yellow/green nasal drainage persists beyond the expected seven to ten day course of a viral infection, bacterial sinusitis is often the culprit. The sinuses are cavities in the skull surrounding the nose: a pair under the cheek bones, a pair above the eyebrows, a single one directly behind the nose, and several small ones along the bridge of the nose between the eyes. Sinusitis according to the medical dictionary means “inflammation of the sinus cavities”. In the case of bacterial sinusitis, this means that the inflammation, or swelling, of the sinuses is due to a bacterial infection. Cough may be the only manifestation of sinus disease in both children and adults. Persistent daytime or nighttime cough – with or without a history of wheezing – in a child with a normal chest examination should alert the doctor to think of sinusitis. Adults will more often describe the classic symptoms of headache, postnatal drip and facial pressure. Nasal allergies, often called hay fever, predispose people to develop sinus congestion and eventually sinusitis. Allergies should be suspected in children with a family history of allergies, recurring sinus infections, a seasonal pattern of symptoms, worsening nasal symptoms when exposed to animals or dust, and other allergic conditions such as asthma, eczema or food allergy. Children as young as one year old can undergo simple allergy skin testing at Windom Allergy to determine whether they are allergic. Recognizing and treating the allergic reactions in the nose will prevent the first step of the development of a sinus infection.