Paroxysmal hemicrania: symptoms, diagnosis and indomethacin treatment

Paroxysmal hemicrania (often shortened to PH) belongs to a small family of headaches in which severe pain on one side of the head is accompanied by signs from the autonomic nervous system, such as a watering eye or a runny nose. The best known member of this family is cluster headache. OUCH (UK), the UK cluster headache charity, describes paroxysmal hemicrania as involving one-sided attacks that have very similar characteristics of pain and associated cranial autonomic symptoms to cluster headache.

The main difference is timing. According to OUCH (UK), the attacks are much shorter and happen many more times a day. An average attack lasts twenty minutes, though it can be as short as two minutes or as long as 45 minutes, and ten attacks a day is typical, with up to 40 possible. That is why people sometimes describe the pattern as relentless: there is hardly time to recover between attacks.

It is rare, and many people go through several diagnoses before it is recognised. Because treatment is so specific, getting the right label matters.

The NHS description of cluster headache is a useful guide to the shared symptoms, because paroxysmal hemicrania produces a very similar picture. The NHS lists sharp, burning or piercing pain, usually on one side of the head and around the eye, headaches that start and stop quickly without warning, and pain that makes you feel restless so that you want to walk about.

• A red and watering eye on the same side as the pain.

• Drooping and swelling of the eyelid on the same side.

• A smaller pupil in the eye on the same side.

• Face sweating.

• A blocked or runny nose.

• Feeling sick.

There is no blood test or scan that proves paroxysmal hemicrania. The NHS says of the related condition cluster headache that there are no specific tests: a GP asks about the pain, its location and frequency and any other symptoms, and may refer you to a specialist for a brain scan to rule out other causes. The same logic applies here. A clear history, ideally supported by a headache diary showing how many attacks happen each day and how long each lasts, is the most important part of the assessment.

OUCH (UK) notes that a course of indomethacin is often used as a screening investigation, partly to rule out cluster headache. A dramatic and consistent response to indomethacin supports the diagnosis. A clinician will decide on the dose, duration and follow-up.

It is also worth saying that migraine can have similar features, which the NHS highlights for cluster headache. Careful differentiation is therefore a specialist task.

Indomethacin is the treatment that defines this condition. OUCH (UK) says paroxysmal hemicrania responds almost absolutely to this non-steroidal anti-inflammatory drug. It is a prescription medicine, and it should be started and adjusted by a doctor who can monitor for side effects, and the leaflet supplied with the medicine and the prescriber will explain side effects and interactions.

The NHS lists triptan injections or nasal sprays, oxygen and a small device that gives mild electrical pulses to the neck as treatments for cluster headache attacks, and says paracetamol and ibuprofen do not work for cluster headache. Because paroxysmal hemicrania has its own specific medicine, the choice of treatment is a decision for the specialist.

If indomethacin is not tolerated, the specialist can discuss alternatives. People should never stop or change a prescribed dose without advice from the prescriber.

The NHS advises getting an urgent GP appointment or calling 111 if a severe headache comes with jaw pain when eating, blurred or double vision, a sore scalp or numbness or weakness in the arms or legs, because these can be signs of temporal arteritis.

The NHS also says to call 999 or go to A&E if you have a drooping eyelid or one pupil smaller than the other for the first time, even if you have already been diagnosed with a cluster-type headache.

With the right medicine, many people experience a marked reduction in attacks. The NHS suggests that a headache diary can help you understand triggers for cluster headaches, and the same habit is helpful here. Recording attack counts, duration, side, associated symptoms and medicine doses helps your specialist fine-tune treatment.

Living with frequent attacks can affect sleep, work and mood. OUCH (UK) provides information on workplace rights and reasonable adjustments, and a GP can discuss mental health support if the condition is wearing you down.

On the NHS, diagnosis usually involves a GP and a neurology referral, with the waiting time depending on the area. Some people choose to see a private neurologist or headache specialist for faster access to an assessment. The key clinical step, a supervised indomethacin trial, is the same either way.