The causes of cold headache may be caused by viral infection, fever, nasal congestion, viral encephalitis and so on. 1. Viral infection: Colds are mainly caused by viral infection, which causes systemic inflammation and produces inflammatory mediators such as prostaglandins, leading to headaches. 2. Fever: If a cold causes recurrent fever or high fever that does not go away, the blood vessels in the head will dilate and cause headaches. 3. Nasal congestion: colds are often accompanied by nasal mucosal congestion and edema, nasal congestion and other symptoms, which can indirectly cause headaches. 4. Viral encephalitis: If the cold is serious, it can be complicated by viral encephalitis, meningoencephalitis, etc., which will cause headache and may be accompanied by high fever and convulsions. Headache can also be caused by other diseases, such as repeated headache symptoms do not improve or aggravate, it is recommended to consult a doctor in a timely manner, under the guidance of standardized treatment.