What is a hallmark symptom of cluster headaches?

A hallmark symptom of cluster headaches is indeed severe, unilateral, periorbital pain. This type of headache is characterized by intense, localized pain that typically occurs on one side of the head, often around or behind the eye. The pain is described as excruciating and can be accompanied by autonomic symptoms such as tearing, nasal congestion, or facial sweating, which are also distinguishing features of this headache type.

In contrast, bilateral pain is more characteristic of tension-type headaches or some migraines. Mild, band-like pressure is typically associated with tension headaches, which are different from the severe nature of cluster headaches. Throbbing pain with nausea is often seen in migraine headaches rather than cluster headaches, where the pain is generally more constant and is not typically throbbing. Recognizing these specific features of cluster headaches is crucial for accurate diagnosis and effective management.