What is Chronic Daily Headache (CDH)?
A patient who has headaches as many days as not — at least 15 days a month — is said to have chronic daily headache (CDH). CDH is not a specific type of headache, but rather a descriptive term applied to any number of headache types. Primary headaches that can occur on a daily or near daily basis include:
- hemicrania continua
- idiopathic intracranial hypotension
- mixture of types (most commonly migraine and tension).
While tension-type headaches are the most common CDH, they are relatively mild and tolerable. The majority of CDH cases fall into one of two categories, both related to migraine.
Medication overuse headache (rebound), is a CDH caused by the patient’s own use of pain relievers. While the condition is frustrating and disabling, it is potentially curable.
A more difficult type and all too common CDH is a “transformed migraine”— migraines that over time become more and more frequent, blurring together until there is a 24-hour-a-day continuous background headache with occasional superimposed more severe migraine symptoms. Transformed migraine headache is extremely difficult to treat, and acts more like a chronic pain syndrome than a migraine in terms of its poor response to typical migraine drugs. Some researchers believe that years of chronic, frequent migraines can cause permanent scarring or other changes in the brain creating this type of intractable CDH, which may not be curable. While there may not be a “magic bullet” for such cases, many patients can be effectively managed with a variety of treatments to substantially reduce pain and disability.
Because out of control migraines can transform into a CDH that is difficult to treat, it is very important to establish good preventive regimen as early in life as possible.
Over 90 percent of patients with CDH have co-existing psychiatric problems, most often anxiety or depression (or both). This makes an already challenging condition even harder to treat. In general, such patients will not improve without some sort of co-existing psychiatric care, counseling, biofeedback, or the like. Unfortunately, few patients choose to undergo this necessary step toward improving their condition and reducing their disability.