How can I differentiate between cluster headaches and other types of primary headaches in a patient presenting with unilateral head pain?

To differentiate cluster headaches from other primary headaches in a patient with unilateral head pain, consider the following key features:

• Location and laterality: Cluster headaches typically present with unilateral pain around or above the eye and along the side of the head/face, whereas tension-type headaches are usually bilateral and migraines can be unilateral or bilateral ¹.
• Pain quality and intensity: Cluster headache pain is severe or very severe and can be sharp, boring, burning, throbbing, or tightening. Tension-type headache pain is pressing/tightening and mild to moderate, while migraine pain is pulsating and moderate to severe ¹.
• Duration: Cluster headaches last 15 to 180 minutes per attack, occurring from once every other day to 8 times a day, often in bouts lasting weeks or months. Migraines last 4 to 72 hours, and tension-type headaches can last from 30 minutes to continuous ¹.
• Associated autonomic symptoms: Cluster headaches are accompanied by ipsilateral autonomic symptoms such as red and/or watery eye, nasal congestion or runny nose, swollen eyelid, forehead and facial sweating, constricted pupil, and/or drooping eyelid. These are not features of migraine or tension-type headache ¹.
• Effect on activities: Cluster headaches cause restlessness or agitation during attacks, whereas migraines cause avoidance of routine activities, and tension-type headaches do not aggravate daily activities ¹.
• Response to treatment and referral: A first bout of cluster headache requires specialist assessment and possibly neuroimaging. Acute treatment includes oxygen and subcutaneous or nasal triptans, unlike tension-type headache or migraine ⁴.

Using a headache diary to record frequency, duration, severity, associated symptoms, and medication use over at least 8 weeks can aid differentiation between cluster headache and other primary headaches ¹,⁴.