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Diagnosing Headaches: Determining The Cause


If a patient presents with a new headache or worsening headaches, it is vital to determine the most likely cause of the headache and then assess whether it is dangerous or life-threatening. The brain itself is insensitive to pain because it lacks pain receptors. Instead, headaches are generally triggered by irritation of the meninges or blood vessels.

Types of Headaches

There are two main types of headache:

  • Primary headaches: They are very common and unpleasant but not dangerous.
  • Secondary headaches: Most are dangerous and have associated red flag symptoms. However, secondary headaches can mimic primary headaches, for example, migraines. Also, sometimes patients with a history of a primary headache disorder can then later develop a secondary headache due to another cause. These patients usually report a change in their headache character.

Evaluation of Headache

There are several questions that are helpful to distinguish among the different types of headache:

  1. Age of onset: This is important because many of the benign primary headache conditions like migraines start in childhood or early adulthood.
  2. Frequency and duration: You will also want to determine how quickly the headache reaches maximum intensity as well as the location and quality of the headache.
  3. Associated features: This will help determine the cause of the headache, as many primary headaches have specific associated features such as autonomic symptoms, presence or absence of aura (eg, visual aura), and conjunctival irritation and injection.
  4. Medication history: Current medications, medication trials, over-the-counter medications, and how often they are used.
  5. History: Gathering a history of head trauma, infections, and when the headache occurs (eg, with menstruation or position changes) as well as family history will help determine the cause of the headache.

Exam and Best Tests

An exam will be helpful in determining if the headache is life-threatening or dangerous. The following should be looked at during a headache exam:

  • Check for pain on neck movement
  • Check range of motion of neck
  • Kernig’s sign and Brudzinski’s sign if concern for meningitis
  • Sensory example for allodynia
  • Fundoscopic example to check for papilledema
  • Visual acuity
  • Visual fields
  • General neurological example to check for focal findings


If there are concerning symptoms or signs or focal neurologic deficits, a further workup with an imaging study may be helpful.

  • If headache is acute in onset or if there is concern for hemorrhage, mass lesion, or hydrocephalus, run a CT of head without contrast.
  • For chronic headaches with atypical features, run an MRI of head.
  • If there is concern for infection or you want to check intracranial pressure, a lumbar puncture is helpful if there are no signs of mass effect on neuroimaging.


Red Flag Symptoms

Be vigilant for red flag symptoms and signs that indicate a potentially dangerous or life-threatening cause of the headache. These include:

  • Thunderclap headache: Very severe headache that reaches its maximum severity immediately.
  • Positional headache: Headache that substantially changes in intensity in association with position. For example, if the headache is only present standing up and goes away lying down, that could indicate a low pressure in the cerebrospinal fluid.
  • Headaches initiated by exertion: Headache starting while coughing, sneezing, and/or straining.
  • New headaches: Especially if older than 50, or if there are medical conditions that make worrisome headaches more likely.
  • Substantial change in headache pattern: Significant increase in headache frequency or significant change in headache characteristics, especially in patients with chronic headaches.
  • Constant headache always in the same location of the head: This can be a red flag for focal lesion.
  • Worrisome neurologic symptoms: An aura with quick onset that lasts longer than 60 minutes or does not resolve requires medical attention. Other concerning symptoms are weakness on one side of the body, change in level of consciousness, or significant difficulty walking.
  • Systemic symptoms: These include fever, chills, and night sweats.

Treatment Options

Once the type of headache is confirmed, a tailored treatment plan can be created. According to Stanford Health Care2, the main treatment categories used to manage headaches include:

  •  Rescue: Treatment for when a headache is staring you in the face
  • Prevention: Treatments aimed at keeping headaches from developing
  • Lifestyle modification: Strategies to identify, modify, and eliminate triggers that can contribute to headaches
  • Complementary medicine strategies
  • Inpatient care

The course of treatment will largely depend on the type of headache but also the patient and their response to treatment. Some treatments may be more effective with specific patients than others.


Headaches are a common complaint but can also be potentially life-threatening and reflect a more dangerous underlying disease. Knowing red flag headache symptoms can be extremely helpful as identifying the dangerous cases quickly and accurately is crucial. In such cases using a diagnostic decision support system, like VisualDx, may be extremely helpful.  

VisualDx is proud to offer ongoing in-depth webinars on a variety of clinical topics in our Clinical Education Series. This article is adapted from our Clinical Education Series webinar, Diagnosing Headaches, presented by Dr. Carolyn Zyloney. You can listen to the full webinar here and follow us on Facebook, Twitter, Instagram, or LinkedIn to learn about upcoming webinars.




1. VisualDx. “Diagnosing headaches.” YouTube, commentary by Carolyn Zyloney, MD, 15 June 2018,

2. Headache treatment and headache relief. Stanford Health Care. Accessed June 24, 2019.



About VisualDx

VisualDx is an award-winning diagnostic clinical decision support system that has become the standard electronic resource at more than half of U.S. medical schools and more than 1,500 hospitals and institutions nationwide.  VisualDx combines clinical search with the world's best medical image library, plus medical knowledge from experts to help with diagnosis, treatment, self-education, and patient communication. Expanding to provide diagnostic decision support across General Medicine, the new VisualDx brings increased speed and accuracy to the art of diagnosis. Learn more at