Among the complaints from patients presenting to outpatient practices, headache is one of the most common. Even the most experienced providers often have a difficult time formulating a diagnosis and effective treatment plan. The authors of this chapter evaluate some of the imperative concepts of headache diagnosis, including headache-specific history, physical examination, warning signs of secondary headache disorders, and when to contemplate further diagnostic studies. The criteria used in making a specific diagnosis are located in the International Headache Society’s International Classification of Headache Disorders, second edition (ICHD-2).¹

A thorough headache evaluation should begin with the determination of whether a headache is a primary or secondary headache disorder. Primary headache disorders lack an underlying cause, but secondary headaches are attributable to an identifiable pathologic cause. Treatment of underlying pathology can at times lead to a cessation of headaches in the case of secondary headaches.

The most important tool in formulating a headache diagnosis is a proper history, which should include past medical history; surgical history; medications; allergies; and family history, including headaches. A thorough medication history should include previous medications that have been used for the abortive and preventive treatment of headache. To ensure adequate trials of these headache medications, dose, duration of treatment, effectiveness, and side effects should be recorded for each medication.

A headache history should begin with the genesis of the headache. For many patients with primary headache disorders, headaches can begin during adolescence or even childhood. In patients with a long history of headaches, recall can often be an issue, but recalling any events that may have precipitated the headaches, such as head trauma, infections, or surgery, is crucial. The features of individual headaches should also be recorded. These features should include intensity, quality, location, radiation, and duration of individual headaches.

Pain intensity can be difficult to assess, but it is an important headache feature in terms of establishing a diagnosis and monitoring improvement with treatment. Although helpful, a visual analog pain scale of 0 to 10 with zero being no pain and 10 being the worst pain imaginable can often lead to an exaggeration of pain. In clinical practice, it is common for a patient to complain of a 9 of 10 pain in the office while being able to converse while sitting comfortably in no clear distress. As such, associating disability ratings to this scale may help correct for this subjective exaggeration. Below is a combined pain and disability scale that can be used to assess headache intensity.²

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  1 to 3 of 10 indicates mild pain with no significant impairment of function.

  
  
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  4 to 6 of 10 indicates moderate pain with some impairment of function.

  
  
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  7 to 10 of 10 indicates severe pain with complete impairment of function.

When addressing frequency, it should be made clear that total number headache days per month is being assessed rather than just severe headache days. It is useful to confirm this number by asking the number of headache-free days per month. For example, if the patient responds to headache frequency questioning by claiming to have 15 headache days in a 28-day month, the patient should be asked if he or she has 13 headache-free days per month for confirmation.

Some other headache features that should routinely be assessed include the presence of photophobia, phonophobia, osmophobia, nausea, vomiting, and cutaneous allodynia. Although some patients may deny these features, asking questions regarding pain behaviors can at times provide a clearer establishment of associated features. For example, a patient may initially deny photophobia and phonophobia on direct questioning. When asked specifically during a severe headache, the same patient may prefer to rest in a dark, quiet room.