A cold without a fever but headache may be caused by lack of sleep, but also may be the cause of pathogen infection and by the cold air stimulation. 1. lack of sleep: after the cold easily lead to the patient’s body resistance to decline, if the work and rest is not regular, a long time to stay up late, easy to lead to the brain nerves have been in a state of fatigue, so it will lead to the patient’s cold does not have a fever but headache. 2. Pathogen infection: Colds are usually caused by pathogen infection, which will stimulate the nerves in the head after invasion, leading to expansion and contraction of cerebral blood vessels, causing headaches. 3. Cold air stimulation: If you don’t keep your body warm after catching a cold, the cold air stimulation will lead to the contraction and expansion of blood vessels inside and outside the skull, resulting in headaches. In addition, excessive fatigue, migraine headache is also easy to lead to patients with a cold without fever but headache, the patient needs to go to the hospital to do a comprehensive examination to clarify the cause of the disease.