Anyone who has suffered from Influenza has probably experienced the headache that accompanies this infection. Many viral infections can either directly or indirectly cause headache. The headache related to these viral infections appears to be related to the fever, the body's production of interferon, and other elements of the immune system combating the viral infection. Headache may also be associated with those viral infections that affect the upper respiratory tract, such as the common cold virus, the Rhinovirus. This particular infection may produce intense congestion in the nasal passages, which at times causes a blockage of the sinus drainage passages, and can also cause headaches. A severe headache may also result from viral infections that specifically attack the brain and its coverings, such as encephalitis and meningitis.
Chronic viral infections have been implicated as a cause of headache and other conditions, such as the chronic fatigue syndrome. However, there is scant evidence to support chronic viral infection as a cause of chronic headache and substantial medical research that negates this theory.
Regardless of the role of chronic viral infections in these disorders, there is considerable evidence that suggests antidepressant medications may be helpful in controlling these conditions.
Sometimes a benign viral infection may set off a cycle of chronic daily headaches that do not have typical features of migraine or tension-type headache. The headaches typically are aggravated by exertion or straining and usually improve in a few weeks or months.