Sinusitis in children looks different than sinusitis in adults. More often than not, children show signs of sinusitis by coughing, bad breath, crankiness, low energy, and even swelling around the eyes, along with thick yellow-green nasal or post-nasal drip.   These Signs and symptoms of pediatric sinusitis may include your child has an infection:   - Cold lasting longer than 10-14 days - Low or even a high-grade fever - Thick yellow-green looking nasal drainage for at least three days in a row - Post-nasal drip, this can include sore throat, cough, bad breath, nausea and/or vomiting - Headache, usually occurs in children aged six or older - Irritability or tiredness - Swelling around the eyes   Most of the time children that are diagnosed with a viral sinus infection will improve by getting treated for the symptoms they are showing, but antibiotics can only be considered in severe cases of bacterial sinusitis.   Your child’s sinuses are not fully developed until their later teen years. Pediatric sinusitis can be difficult to diagnose because the symptoms children show can be caused by other problems, such as viral illness or allergies.