Smoking and second-hand smoke from cigarettes, cigars, and pipes can contribute to headaches for both the smoker and the non-smoker. Nicotine, one of the components of tobacco, triggers blood vessels to constrict, reducing blood flow to the brain and the covering of the brain (the meninges). Decreased blood flow leads to depressed brain activity, which is a major component of migraines. In addition, reducing the blood flow to the meninges can induce severe pain, which may be felt in the back of the head or in the face. Nicotine also may stimulate the pain-sensitive nerves as they pass through the back of the throat, further increasing the tendency toward head pain In some people, this stimulation can contribute to headaches. Usually, by removing the stimulus (nicotine), headaches will be relieved. Quitting smoking or reducing exposure to secondhand smoke is especially helpful for those with cluster headaches. In one study of patients with cluster headaches, those who reduced their tobacco use by less than one-half pack of cigarettes per day found their headaches were decreased by 50 percent.
Allergy to smoke, as well as odor sensitivity, can also cause migraine headaches in some people. By avoiding situations or places where smoking is permitted, or by quitting smoking, most people can reduce the onset of a migraine headache.