Upper respiratory tract infections are mostly caused by viruses, especially rhinoviruses, coronaviruses, adenoviruses, and influenza viruses. Bacteria can sometimes cause secondary infections. Common symptoms include cough, sore throat, nasal congestion, and sinus pain/pressure. Treatment focuses on relieving symptoms with medications like paracetamol and ibuprofen. Antibiotics are only used if bacteria are confirmed to be causing the infection. Complications can potentially involve the sinuses, ears, or in rare cases, more serious conditions.