There are many reasons for a headache when coughing hard, such as upper respiratory tract infection, cerebral hypoxia, sinusitis, scalp inflammation, cervical spondylosis, systemic diseases and so on. 1. Upper respiratory tract infection: upper respiratory tract infection will not only cough, but also may be accompanied by headache, nasal congestion, runny nose, coughing up phlegm, and so on, so it will cause a hard cough headache phenomenon. 2. Cerebral hypoxia: certain diseases can cause cerebral hypoxia, such as cerebral space-occupying lesions, cerebrovascular lesions, etc., which may lead to headache when coughing hard. 3. Sinusitis: sinusitis due to nasal irritation can cause coughing, but also may be accompanied by rhinogenic headache, so there will be a cough on the phenomenon of headache. In severe cases, it can cause trigeminal neuralgia, so it shows headache. 4. Scalp inflammation: If there is bacterial infection or viral infection on the scalp, due to the vibration conduction of coughing, it can cause pain in the position of inflammation, so there is the phenomenon of headache when coughing hard. 5. Cervical spondylosis: cervical spondylosis can also lead to headache when coughing hard, mainly cervicogenic headache, accompanied by cervical spine activity limitation, pain, numbness of the upper limbs and other symptoms. 6. Systemic diseases: hypertension, migraine, vascular neurological headache and other diseases, due to coughing too hard, may also induce a headache phenomenon. There are many reasons for a hard cough headache, it is recommended to go to the hospital in a timely manner, improve the relevant examination, identify the cause of the disease, take standardized treatment in accordance with the medical advice, do not ignore the symptoms, take it lightly.