A headache defined by the drug that switches it off.

THE CONDITION · HEMICRANIA CONTINUA

Hemicrania continua is a headache that never fully goes away and never swaps sides. Flares of severe pain bring a watering or red eye, drooping lid or blocked nostril on the same side.

It is also a headache that responds completely to one specific medication. That response is both the treatment and the diagnostic test. That makes this one of the most important headaches not to miss.

Why it matters out of proportion to how common it is

It is uncommon. But it is often misdiagnosed as chronic migraine or cervicogenic headache (headache from the neck). Then it gets treated for years without success, even though a specific, highly effective treatment exists. The cost of missing it is unusually high. That is why it belongs on a site like this one.

What are the symptoms of hemicrania continua?

• Strictly one-sided and continuous. It never fully goes away and never swaps sides.
• A moderate background ache, with flares of severe pain on top.
• During flares, autonomic features on the same side: watering or red eye, drooping lid, blocked or running nostril.
• Often a feeling of something in the eye, or restlessness during the flare.
• Present for more than three months without a break.

The combination of continuous, strictly one-sided, and autonomic features during flares is the pattern. Migraine is not continuous. Cluster is not continuous. cervicogenic headache is not usually autonomic.

How do you stop hemicrania continua?

Hemicrania continua is defined partly by a complete response to indomethacin. A supervised trial at a proper dose both diagnoses and treats it. A full response confirms it. No response argues strongly against it.

This is a trial a clinician supervises, not something to try yourself. The drug has stomach and kidney issues that need managing. The dose and length also have to be adequate, or the test means nothing. But say you have a continuous one-sided headache that has never been tested this way. That is a specific and fair thing to ask about.

What can be mistaken for hemicrania continua?

It is most often mistaken for tension-type headache and migraine. The background ache gets blamed on tension-type. The flares get blamed on migraine. So the person is treated for two disorders they do not have. The feature that ties it together is that it never fully stops and never changes side. That is exactly the detail that gets lost when a history is rushed. Why side-locked matters.

Frequently asked questions

What is hemicrania continua?

A continuous, strictly one-sided headache with autonomic features during flares. It is defined by a complete response to indomethacin.

How is it diagnosed?

Clinically. A supervised indomethacin trial at a proper dose acts as the test that confirms it.

Could my chronic migraine actually be this?

Ask about it by name if it is strictly one-sided, never fully lets up, and has autonomic features during flares.

Can I just try indomethacin?

No. It needs supervision for stomach and kidney safety. Too low a dose or too short a trial gives a false negative. That closes the question wrongly.

How long does hemicrania continua last?

It is continuous. By definition it has been present for more than three months without a break, and it never fully goes away and never swaps sides. A moderate background ache runs all the time, with flares of severe pain on top. During those flares the eye may water or redden, the lid may droop and the nostril may block on the same side.

How is hemicrania continua different from migraine or cluster headache?

Three features together set it apart. It is continuous. It stays strictly on one side. And its flares bring eye and nose symptoms on that same side. Migraine is not continuous, and cluster headache is not continuous either. Cervicogenic headache from the neck does not usually bring those eye and nose symptoms. That combination is the pattern to name when you are seen.

Can hemicrania continua be treated?

Yes. It responds completely to one specific medication, indomethacin. That is why it is one of the most important headaches not to miss. A clinician has to supervise the trial, because the drug needs stomach and kidney monitoring. The dose and length of the trial also have to be adequate. A full response both treats the headache and confirms the diagnosis.

Differentials to read

• Side-locked headache
• Cluster headache
• Cervicogenic headache
• Chronic migraine
• When to get a second opinion