Primary and secondary/acquired types occurred. The
primary type occurs in children, especially boys, whereas the secondary form
is found almost entirely in adults who have an underlying disease (typically
polycythemia vera, essential thrombocythemia, chronic myelogenous leukemia,
and idiopathic myelofibrosis and other forms of myeloproliferative
disorders) but may also include connective tissue disorders, autoimmune
collagen vascular diseases (e.g., rheumatoid arthritis, Systemic Lupus
Erythematosus (SLE)), infectious diseases (e.g., AIDS), neurologic diseases (e.g.,
multiple sclerosis, neuropathies), cardiovascular disorders (e.g., arterial
hypertension, arteriosclerosis), diabetes mellitus, and drugs (e.g., iodine
contrast injection, vaccinations, calcium antagonists). The clinical
appearance of both primary and secondary forms is basically identical. The
pathognomonic diagnostic criterion of secondary erythromelalgia is rapid
pain relief that lasts a few days after one low dose of aspirin, which
irreversibly inhibits platelet cyclooxygenase activity. Heat intolerance
(and aggravation of symptoms with standing or exercise) and relief of
symptoms with cooling (and elevation of the affected body part and rest) are
hallmarks of erythromelalgia, whereas warmth exposure not only triggers
flaring but also increases the severity of the episode. Pain relief from
immersing the affected body parts in ice water is considered almost
pathognomonic for the disease (similarly, immersing a limb in warm water may
trigger an attack). In all cases of newly diagnosed erythromelalgia,
polycythemia, thrombocythemia, and other diseases (neuropathies) must be
excluded by appropriate laboratory and diagnostic studies. Regular followups
are recommended.