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Disease Profile

Paroxysmal hemicrania

Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.


US Estimated

Europe Estimated

Age of onset






Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.


dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.


Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable



Nervous System Diseases


The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs.

Orpha Number: 157835

A rare primary headache disorder characterized by multiple attacks of unilateral pain that occur in association with ipsilateral cranial autonomic symptoms. The hallmarks of this syndrome are the relative shortness of the attacks and the complete response to indomethacin therapy.

Paroxysmal hemicrania (PH) prevalence is unknown. There is a male-to-female ratio of 1:1.

Clinical description
The mean age of onset is 40 years (range 3-81 years). PH patients experience purely unilateral, severe to very severe attacks of head pain. The pain is often in the temporal, orbital or supraorbital region. The pain has an abrupt start and cessation and is accompanied by ipsilateral autonomic features, including lacrimation, conjunctival injection, rhinorrhoea, nasal congestion, periorbital oedema, facial flushing, miosis and/or ptosis. PH attacks last 2-30 minutes and occur more than 5 times a day up to 40 times a day with a mean of 11 a day. Patients can have unilateral photophobia and phonophobia ipsilateral to the side of the attack. Osmophobia, nausea or vomiting during the attacks has been reported. Although attacks are most usually spontaneous, attacks can be triggered by neck movements, or pressure over the neck or greater occipital nerves. PH can be classified as episodic or chronic, depending on the duration of pain-free period when untreated. Episodic paroxysmal hemicrania patients have bouts lasting from 7 days to 1 year and separated by pain-free periods more than 3 months, whereas in chronic patients the pain-free period is less than 3 months. As this is a primary headache disorder, patients have normal neurological tests.

Etiology remains unclear.

Diagnostic methods
Diagnosis is based on clinical history and response to indomethacin. Patients with suspected paroxysmal hemicrania should undergo an oral indomethacin trial or placebo-controlled intramuscular indomethacin test. In adults, one could start with 25mg three times a day, titrating up to 75mg three times a day over the course of 3 weeks. With intramuscular indomethacin 100-200 mg could be used.

Differential diagnosis
Cluster headache is the main differential diagnosis, given the overlap in duration of the attacks. It is very important to differentiate PH from cluster headache, as treatment differs greatly.

Genetic counseling
Rare cases of familial PH have been reported.

Management and treatment
A complete response to indomethacin confirms the diagnosis of PH. Treatment with indomethacin with a median dose of 150 mg/day (ranging from 30-300mg/day) results in dramatic relief of the disabling symptoms caused by PH.

This is a debilitating headache condition if not accurately diagnosed and managed.

Visit the Orphanet disease page for more resources.


This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Medical Terms Other Names
Learn More:
80%-99% of people have these symptoms
Intermittent migraine headaches
Migraine headache
Migraine headaches

[ more ]

Recurrent paroxysmal headache
30%-79% of people have these symptoms
Conjunctival hyperemia
Increased tears
Watery eyes

[ more ]

Fear of loud sounds
Extreme sensitivity of the eyes to light
Light hypersensitivity

[ more ]

Drooping upper eyelid
Nasal inflammation
Runny Nose
5%-29% of people have these symptoms
Diabetes mellitus
Focal sensory seizure with olfactory features
Constricted pupils
Pupillary constriction

[ more ]

Nausea and vomiting
Neck pain
Palpebral edema
Fullness of eyelids
Puffy eyelids
Puffy lids
Swelling of eyelids

[ more ]

Restless legs
Stiff neck
Neck stiffness


Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

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    These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

    Where to Start

      In-Depth Information

      • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
      • MeSH® (Medical Subject Headings) is a terminology tool used by the National Library of Medicine. Click on the link to view information on this topic.
      • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
      • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
      • PubMed is a searchable database of medical literature and lists journal articles that discuss Paroxysmal hemicrania. Click on the link to view a sample search on this topic.