Neurologists and headache experts like to classify things, and when it comes to headache there is a lot to classify. Headache can be a symptom of many different diseases and disorders, in addition to being a disorder itself. All told, there are over 300 types and causes of headache identified! That is a much longer list of possible diagnoses to be considered than exist for most diseases or disorders in the many areas of medicine.
When the International Headache Society (IHS) published its classification of headache disorders in 1988 it was 96 pages long, with 15 pages on migraine alone! While some chronic headache subtypes were included, such as chronic cluster headache and chronic tension-type headache, the concept of "chronic daily headache" was left out.
In retrospect, this omission was most interesting, since chronic daily headache is not an unusual condition in medical clinics. In fact, it’s one of the most common complaints seen by headache specialists.
Chronic daily headache is generally accepted to refer to a broad group of headache disorders that are daily or near daily, persistent and continuous for the most part. Chronic daily headache patients have headaches for more than 15 days per month or 180 days per year.
The great majority of these daily or near-daily headaches turn out to be "benign"—that is, they do not indicate the presence of a serious underlying disease, such as a brain tumor. However, it is important to seek medical attention to rule out any rare but potentially life-threatening disorders. Just as important, the benign types of chronic daily headache can often be effectively managed with good medical care.
The two most common types of chronic daily headache are chronic tension-type headache and transformed migraine. Recent studies suggest that about 4% of the general population have chronic daily headaches. Between 40%-60% of patients seeking treatment from headache centers have daily or near-daily headache, that is, chronic daily headache. Some of these patients have chronic tension-type headache but the majority have transformed migraine. Often these headaches are associated with overuse of medications.
Chronic Tension-Type Headache or Transformed Migraine?
Nearly everyone can relate to the concept of episodic tension-type headache, as most headache sufferers have had these from time to time. The pain is usually mild to moderate in severity and it may have a pressing or tightening quality. The headache is felt on both sides of the head and is not worsened by activity. There is no vomiting but loss of appetite or light or sound sensitivity may occur. Chronic tension-type headache is defined as headaches following this pattern that occur at least 15 days per month for 6 months.
People with chronic tension-type headache may have no history of distinct migraine. They frequently use excessive amounts of painkillers or analgesics, and they may have symptoms of depression. They may have a history of episodic tension-type headache that evolved into the more frequent pattern.
Patients with transformed migraine have a history of migraine attacks, with or without aura, when they were younger, and over several years the migraine attacks become more frequent.
Soon the migraine characteristics give way to chronic daily headache with a daily or near-daily background headache that often resembles a typical "tension-type headache." Many still have some headaches that resemble those of their prior migraine attacks, although some will not.
In essence, the background "tension-type headache" probably is "mild migraine" for lack of a better word. It "behaves" like tension-type headache but probably is not biologically. You could say that patients with transformed migraine have "chronic migraine," but this concept is not universally accepted.
Many migraine patients will recognize the pattern of transformed migraine in their life history of migraine. They have a history of chronic daily headache but their history, unlike chronic tension-type headache, is on a background of migraine headache. Of course it is possible to have both patterns, but most people with chronic daily headache will have one or the other.
The Importance of the Diagnosis
So what is the "big deal" about defining and separating out transformed migraine from chronic tension-type headache and other rarer forms of chronic daily headache? First, clear definitions of these headache types help doctors (and patients) to identify problems that may be contributing to the headaches and to select the proper course of treatment.
If, for example, the patient has transformed migraine, there is a very good chance these headaches can be effectively treated. The main reason that this is true is that the majority of patients with transformed migraine use excessive amounts of analgesics--some do not, but most do.
So, for people with transformed migraine there is good reason to believe that if the analgesics can be eliminated, then the persistent background headache will gradually go away. They may be able to return to only having their usual intermittent migraine headaches, which for the most part are treatable, as they know from earlier life experiences. The elimination of analgesics in patients with chronic tension-type headache can be beneficial as well, in that many patients may revert to occasional tension-type headache that can be managed.
There is a lot more to learn about chronic tension-type headache and transformed migraine but the above overview should alert you to recognize these particular types of chronic daily headache. It is generally not possible for people to stop overusing painkillers on their own, so you should seek medical attention for assessment and help. It is very important, in the first instance, to "check out" any chronic daily headache to rule out the possibility of serious disease, though the vast majority of patients with headache have normal physical examinations and CT or MRI studies.
Finally, it is vital to remember that these headache disorders cannot be "cured," but they can be managed effectively and controlled. Some patients with these types of chronic daily headache will need to go into the hospital, but most will not. If you have one of these headache disorders you will have to make a major commitment to working with your doctors to get better. If you do so, then there really is a "light at the end of the tunnel," and hope for a better day!
Seeking Treatment for Chronic Daily Headache—What to Expect
It’s important to seek medical attention for daily headaches, first to rule out the possibility of serious disease, and secondly to find out what can be done to control the headaches. Much has been learned about transformed migraine and other forms of chronic daily headache in the last few years, and improved strategies for managing these headaches offer relief for many or most patients.
Since medication overuse is a frequent underlying problem, you can help yourself and your doctor evaluate your headaches if you make an attempt to track your medication use in advance of your office visit. Use a calendar or a daily planner to note down all use of pain medications, both prescription and over-the-counter, including the doses taken.
If painkillers are being overused, then it is necessary to eliminate all analgesic use, including over-the-counter as well as prescription drugs. Unfortunately, the daily headaches will become more severe when the overused medicines are withdrawn. There are several strategies to help control these more severe headaches during the drug withdrawal phase. Some patients are helped by starting a daily headache preventive medicine. For people who have been overusing addictive painkillers, a brief hospitalization may be needed to help with medication withdrawal.
Many people with either transformed migraine or chronic tension-type headache may have other problems, such as depression, that can be identified and treated. Often, people say they are simply depressed because of the headaches, and if they could just get rid of the headaches then the depression would go away too. However, depression increases pain sensitivity, so treating depression itself can help with the headache problem. Also, people who are depressed may have more trouble with following their doctor’s advice (for example, by stopping overuse of painkillers) and they may not be taking care of themselves in terms of good nutrition, exercise and regular sleep habits. There are other conditions that can play a role; for example, the person may be suffering from insomnia, and improving sleep can also help the headaches.
It may take weeks to months before the daily headaches begin to relent, but most patients with transformed migraine and many of those with chronic tension-type headache are able to eliminate the daily headache pattern with time and good medical care.