Harlequin syndrome

What it is

Harlequin syndrome (HSD) is an autonomic disorder occurring at any age and characterized by unilateral flushing and sweating, involving the face and sometimes arm and chest, in condition of thermal, exercise or emotional stress without sympathetic ocular manifestations. However, tonic pupils, parasympathetic oculomotor lesion and pre- or postganglionic sudomotor sympathetic deficit can rarely occur.

Key facts

Prevalence

<1 / 1 000 000

Age of onset

All ages

Inheritance

Not applicable

Classified as

Disease

Prevalence figures describe populations, not individuals, and are often estimates from a single study. Where the figure is an incidence or a birth prevalence, it says so.

Signs and symptoms

These ranges are how often a sign appears across everyone diagnosed, not a prediction for one person — most people have some of these and not others. Orphanet also records findings that are specifically absent in this disease; those are in the data but not listed here.

ICD-10 codes

ICD-10 has no distinct code for most rare diseases, so many are filed under the nearest available one. A shared code identifies the group, not this disease — the ORPHAcode above is what identifies it.

Related health topics

Reached through the ICD-10 categories this disease is filed under, so these describe the broader group rather than this disease specifically.

Cross-references