Which of the following statements is characteristic of cluster headaches?

• A. They are common and affect mostly females.
• B. They have onset in the fifth decade.
• C. They are uncommon, predominantly affecting males with onset typically in the third decade.
• D. They never occur at night.

Answer: (C)

Cluster headaches are a rare, primary headache disorder with very severe unilateral orbital-temporal pain and autonomic symptoms that occur in bursts and often follow a circadian pattern. Epidemiologically, they have a strong male predominance and typically begin in early to middle adulthood, commonly in the third decade.

That combination—uncommon occurrence, male predominance, and onset around the 20s–30s—best fits the statement. They do frequently occur at night, especially during sleep, so the claim that they never occur at night is incorrect. The other options misstate either how common they are, the sex distribution, or the typical age of onset.