J00-J06: Acute upper respiratory infections

J06: Acute upper respiratory infections of multiple and unspecified sites

Acute upper respiratory infections of multiple and unspecified sites comprises a group of infections that affect the upper respiratory tract, which includes the nose, sinuses, pharynx, or larynx. These infections are typically caused by viruses but can also be due to bacteria. They often spread via person-to-person contact, through the air via droplets when an infected person sneezes or coughs, or by touching a surface that an infected person has touched. Symptoms may include a stuffy or runny nose, sore throat, cough, headache, and distinct tiredness. The pathogens usually invade the host's body, multiply, and cause an immune response. This leads to inflammation and swelling of the mucous membranes lining the upper respiratory tract, resulting in the typical symptoms. The disease course is usually self-limiting, meaning it resolves on its own over time, often within a period of one to two weeks.