Causes of Erythromelalgia
The causes of erythromelalgia can be primary (genetic or idiopathic) or secondary to other medical conditions. Erythromelalgia is not caused by infection or trauma but by abnormalities in how blood vessels and nerves respond to heat or exertion.
Primary Erythromelalgia
This form often begins in childhood or adolescence. It may be:
Idiopathic – where no clear cause is found
Inherited – linked to mutations in the SCN9A gene, which affects sodium channels in nerve cells. This leads to increased pain signalling and poor regulation of blood vessel dilation.
Primary cases may worsen over time or remain stable, but there is no cure.
Secondary Erythromelalgia
This form develops in response to another condition. Common causes include:
1. Blood Disorders
Polycythaemia vera
Essential thrombocythaemia
Myelofibrosis
These disorders increase blood cell counts, making the blood thicker and causing abnormal blood flow in small vessels.
2. Autoimmune Diseases
Systemic lupus erythematosus (SLE)
Rheumatoid arthritis
Sjögren’s syndrome
These diseases cause inflammation and affect blood vessels and nerves.
3. Nerve Damage (Neuropathy)
People with small fibre neuropathy may develop erythromelalgia-like symptoms due to abnormal nerve signalling. Diabetes and alcohol abuse are common causes.
4. Medications and Toxins
Some drugs may trigger or worsen symptoms, such as:
Calcium channel blockers
Bromocriptine
Certain antidepressants
Causes of Erythromelalgia In South Africa
In South Africa, erythromelalgia may go unrecognised in patients with underlying blood or autoimmune disorders. Limited access to specialist testing, such as genetic or nerve studies, means diagnosis may be delayed.
Clinicians should consider erythromelalgia in patients with unexplained burning pain and redness in the extremities—especially if the symptoms are heat-sensitive or worsen after exertion.
Understanding the causes of erythromelalgia helps guide treatment and determine whether further testing for associated conditions is necessary.
[Next: Symptoms of Erythromelalgia →]
