The incidence of tension headache is certainly greater than that of migraine. However, most patients treat tension headaches themselves and do not seek medical advice. Like migraine, tension headaches are more common in women than in men. Unlike migraine, they infrequently begin in childhood or adolescence but are more likely to arise in middle age and to coincide with anxiety, fatigue, and depression in the trying times of life. In the large series reported by Lance and Curran, about one-third of patients with persistent tension headaches had readily recognized symptoms of depression. They carried out a controlled and blinded trial that demonstrated benefit from amitriptyline even in those patients who were not depressed. In our experience, chronic anxiety or depression of varying degrees of severity is present in the majority of patients with protracted headaches. Migraine and traumatic headaches may, of course, be complicated by tension headache, which, because of its persistence, often arouses fears of a brain tumor or other intracranial disease. However, as Patten points out, not more than one or two patients out of every thousand with tension headaches will be found to harbor an intracranial tumor, and its discovery has been most often incidental (see further on).
In a substantial group of patients with chronic daily headache, the pain, when severe, develops a pulsating quality, to which the term tension-migraine or tension-vascular headache has been applied (Lance and Curran). Observations such as these have tended to blur the sharp distinctions between migrainous and tension headaches in some cases.
For many years, it was thought that tension headaches were a result of excessive contraction of craniocervical muscles and an associated constriction of the scalp arteries. However, it is not clear that either of these mechanisms contributes to the genesis of tension headache, at least in its chronic form. In most patients with tension headache, the craniocervical muscles are quite relaxed (by palpation) and show no evidence of persistent contraction when measured by surface electromyographic (EMG) recordings. Anderson and Frank found no difference in the degree of muscle contraction between migraine and tension headache. However by contrast, using a laser device, Sakai and associates have reported that the pericranial and trapezius muscles are hardened in patients with tension headaches. Nitric oxide has been implicated in the genesis of tension-type headaches, specifically by creating a central sensitization to sensory stimulation from cranial structures. The strongest support for this concept comes from several reports that an inhibitor of nitric oxide reduces muscle hardness and pain in patients with chronic tension headache (Ashina et al). At present, these are interesting but speculative ideas.
Treatment of Tension Headache
Simple analgesics, such as aspirin or acetaminophen or other NSAIDs, may be helpful, if only for brief periods. Persistent or frequent tension headaches respond best to the cautious use of one of several drugs that relieve anxiety or depression such as amitriptyline given as a single dose at night, especially when symptoms of these conditions are present. Stronger analgesic medication should be avoided. Raskin reports success with calcium channel blockers, phenelzine, and cyproheptadine. Ergotamine and propranolol are ineffective unless there are symptoms of both migraine and tension headache. Some patients respond to ancillary measures such as massage, meditation, and biofeedback techniques. Relaxation techniques may be helpful in teaching patients how to deal with underlying anxiety and stress. Gradual withdrawal of daily doses of analgesics, ergotamines, or triptan medications is an important aspect of treating chronic daily headache.