What Is Paroxysmal Hemicrania? Understanding the Causes and Symptoms

Most people are familiar with the occasional headache. But imagine experiencing sudden, sharp pain on one side of your head multiple times a day—every day. For people living with paroxysmal hemicrania, this is an unfortunate reality.

Paroxysmal hemicrania is a rare but intensely painful type of headache that belongs to a group known as trigeminal autonomic cephalalgias (TACs), a family of headache disorders that affect one side of the head and often involve facial pain or eye symptoms. Though not as widely known as migraine or cluster headache, paroxysmal hemicrania can be just as debilitating and disruptive to daily life.

What Causes Paroxysmal Hemicrania?

The exact cause of paroxysmal hemicrania isn’t fully understood, but researchers believe it may involve abnormal activity in the trigeminal nerve, which is responsible for facial sensation and plays a key role in head pain.

There may also be changes in a part of the brain called the hypothalamus^[1], which helps regulate many body functions, including pain perception. Some scientists suspect that certain hormones or chemical messengers in the brain could trigger these attacks, especially since women seem to be affected more often than men.^[2]

Though it’s not considered hereditary, some people with paroxysmal hemicrania may also have a history of other headache disorders like migraine, which suggests a possible shared mechanism.

Recognizing the Symptoms

The hallmark symptom of paroxysmal hemicrania is brief, frequent attacks of sharp, stabbing pain on one side of the head (as opposed to hemicrania continua, which is characterized by a persistent, continuous headache.) These attacks usually occur multiple times per day and can last anywhere from two to 30 minutes. Other common symptoms include:

• Pain focused around one eye, temple, or forehead.
• Redness or tearing of the affected eye.
• Nasal congestion or runny nose on the same side as the pain.
• Drooping eyelid or small pupil (a condition called Horner’s syndrome).
• Restlessness or agitation during attacks.

These symptoms may sound similar to those of cluster headache, and in fact, the two are often confused. But one key difference is that Paroxysmal Hemicrania tends to involve shorter but more frequent attacks—often five or more per day. Cluster headaches usually come in longer bursts but happen less frequently.

Some people experience chronic paroxysmal hemicrania, where attacks occur daily for years, while others have the episodic form, where attacks come in cycles with pain-free periods in between.

Finding Relief

Living with paroxysmal hemicrania can be exhausting—not just because of the pain, but because it can take time to get an accurate diagnosis. Many people are misdiagnosed with migraines or sinus issues before finally receiving the right label. If you suspect your headaches match the symptoms of paroxysmal hemicrania, it’s important to talk to a health care provider, preferably one who specializes in headache disorders. A neurologist can help confirm the diagnosis and suggest treatment options.

What’s particularly unique about paroxysmal hemicrania is how it responds to a specific medication called indomethacin, a non-steroidal anti-inflammatory drug (NSAID). In fact, a quick and complete response to indomethacin is often used as a way to confirm the diagnosis. However, while indomethacin has long been the go-to treatment, it’s not suitable for everyone—many people cannot tolerate this medication long term due to its side effects. That’s where newer, drug-free treatment options may come into play, like non-invasive vagus nerve stimulation (nVNS), which is emerging as a promising drug-free option for some people with TACs, including paroxysmal hemicrania.

gammaCore™, a handheld nVNS device, stimulates the vagus nerve through the skin on the side of the neck to help interrupt headache pain signals. It’s easy to use, well-tolerated, and doesn’t rely on medication, making it an appealing option for those who can’t take—or no longer benefit from—traditional treatments like indomethacin.

Paroxysmal hemicrania may be rare, but it’s real and treatable. Recognizing the symptoms and understanding the underlying causes is the first step toward getting relief. With more awareness and new treatments on the horizon, people living with this condition have more tools than ever to take back control of their lives.

To see if gammaCore is right for you, visit our clinic finder to locate a health care provider near you, or contact our dedicated Customer Experience team at 888-903-2673 or customerservice@electrocore.com.