Cluster headaches are characterised by episodes of unilateral periorbital pain, conjunctival injection, lacrimation and rhinorrhoea. This form of neurovascular headache most commonly affects middle‑aged men. Headache attacks can last from a few minutes to several hours and can occur many times a day, over several days. Chronic cluster headaches can be separated by headache‑free periods of less than 1 month, or not separated at all.
The usual treatments for acute cluster headache attacks are oxygen inhalation and/or medications such as triptans. Medications such as corticosteroids, verapamil and occipital nerve blocks are used to prevent or reduce the number of attacks. Surgical treatments are reserved for patients with distressing symptoms that are refractory to medical treatments. They include deep brain stimulation to modulate central processing of pain signals and radiofrequency ablation to interrupt trigeminal sensory or autonomic pathways.