Trigeminal autonomic cephalgias (TACs) are a group of rare, chronic headache disorders that are characterized by attacks of severe, one-sided head pain that is accompanied by autonomic symptoms such as tearing, redness of the eye, and congestion of the nose. TACs include several different subtypes, including cluster headache, paroxysmal hemicrania, and hemicrania continua.

Here are a few interesting facts about TACs:

1. TACs are often referred to as "suicide headaches" due to their severe intensity and the fact that they can be incapacitating.
2. TACs are more common in men than in women, and they typically occur in people between the ages of 20 and 50.
3. TACs are thought to be caused by abnormal activity in the trigeminal nerve and the autonomic nervous system.
4. TACs are typically diagnosed based on a combination of clinical presentation and imaging studies such as MRI or CT scans.
5. Treatment for TACs may include medications to prevent or reduce the frequency of attacks, as well as lifestyle modifications such as avoiding triggers that may provoke attacks.
6. In severe cases, treatment may also involve procedures such as nerve blocks or surgical procedures to destroy the trigeminal nerve.