Child colds, also known as acute upper respiratory infections, are acute inflammations of the upper respiratory tract caused by various pathogens. Child colds are mainly caused by bacterial and viral infections, with over 90% being viral. The main viruses involved include rhinoviruses, respiratory syncytial virus, influenza virus, parainfluenza virus, Coxsackie virus, echovirus, adenovirus, and coronaviruses. Viral infections can lead to secondary bacterial infections, with the most common bacterial infections being from Streptococcus pyogenes, Streptococcus pneumoniae, and Haemophilus influenzae. Additionally, Mycoplasma pneumoniae not only can cause pneumonia but is also a cause of upper respiratory infections, and its incidence has been increasing in recent years. Therefore, when a child has a cold, it's also important to consider the possibility of a Mycoplasma pneumoniae infection.