What are the key diagnostic criteria for cluster headaches according to the International Classification of Headache Disorders?

According to the National Institute for Health and Care Excellence (NICE) guidelines, which inform the diagnosis of primary headaches in the UK, cluster headache is diagnosed based on specific headache features ¹. These features are consistent with the International Classification of Headache Disorders (ICHD) criteria, though the provided context directly references the NICE guideline's table ¹.

• Pain Location: The pain is typically unilateral, occurring around the eye, above the eye, and along the side of the head or face ¹.
• Pain Quality: The quality of pain can vary, described as sharp, boring, burning, throbbing, or tightening ¹.
• Pain Intensity: The pain is severe or very severe ¹.
• Effect on Activities: Individuals often experience restlessness or agitation ¹.
• Associated Symptoms: On the same side as the headache, there are usually associated symptoms such as a red and/or watery eye, nasal congestion and/or a runny nose, a swollen eyelid, forehead and facial sweating, and a constricted pupil and/or drooping eyelid ¹.
• Duration: Each headache attack typically lasts between 15 and 180 minutes ¹.
• Frequency: For episodic cluster headaches, attacks occur from once every other day to 8 times a day, followed by a pain-free period of more than one month ¹. Chronic cluster headaches involve attacks occurring from once every other day to 8 times a day, with a continuous pain-free period of less than one month within a 12-month period ¹.

For a first bout of cluster headache, specialist confirmation of the diagnosis and neuroimaging may be needed ².