Erythromelalgia
Definition & triad
- Definition: Paroxysmal functional vasodilation of the acra with the classic triad redness + burning pain + heat sensation, relieved by cooling.
- Synonym: Mitchell's disease (first described 1872).
- Clinical triad: 1) deep red, warm, swollen acra (feet > hands > ears/nose) — 2) burning, often unbearable pain — 3) immediate relief by cooling / cold-water immersion.
- Caution self-injury from ice/cold-water immersion: maceration, frostbite, secondary infection after prolonged immersion.
Classification & pathogenesis
Primary (idiopathic, hereditary)
- Genetics: SCN9A mutation (gain-of-function in voltage-gated sodium channel Nav1.7 of nociceptive neurons) → hyperexcitability of small pain fibres, autosomal dominant. Onset typically 1st–2nd decade.
- Pathomechanism: Inadequate vasodilation combined with small-fibre neuropathy / nociceptive hyperexcitability.
Secondary (acquired, more common)
- Classic associations:
| Group | Triggers | |||
|---|---|---|---|---|
| Myeloproliferative neoplasms (MPN, most common!) | Polycythaemia vera, essential thrombocythaemia, primary myelofibrosis — JAK2-V617F often positive | |||
| Metabolic | diabetes mellitus, hypercholesterolaemia | |||
| Autoimmune / connective tissue | SLE, Sjögren, RA, scleroderma | |||
| Infections | HIV, hepatitis B/C, mononucleosis | |||
| Drugs | Calcium channel blockers (nifedipine, amlodipine), bromocriptine, verapamil , mushroom toxins | |||
| Neurological | multiple sclerosis, peripheral neuropathy | |||
| Paraneoplastic | rare — adenocarcinomas |
Clinical features & diagnostics
- Attack duration: minutes to hours, often evening/night; triggers: heat, exertion, alcohol, dependent legs.
- Examination during attack: symmetric, sharply demarcated deep red discoloration of the acra with marked warmth, occasional oedema; Raynaud's is the key DD (pallor → cyanosis → redness, opposite!).
- Diagnosis: Clinical + provocative warming (30–45 min) reproduces attack; mandatory: FBC + diff + JAK2-V617F (MPN screen!), CRP, glucose/HbA1c, ANA, HIV/HCV serology, ± bone-marrow aspirate if thrombocytosis, small-fibre testing (intra-epidermal nerve fibre density), QST, thermoregulatory sweat test.
Differential diagnoses
Practise Erythromelalgia in the app
Flashcards with spaced repetition, exam questions and spot-the-diagnosis on this topic – in DermaFuchs, free of charge.
In the DermaFuchs app: 1 flashcards · 4 clinical images
Open in browser Download on the App StoreMore vascular skin disorders
- Leukocytoclastic vasculitis
- Lichen aureus
- Superficial thrombophlebitis
- Great saphenous vein varicosity
- Deep vein thrombosis
Note: This page is intended for medical education and does not replace diagnosis or treatment decisions in individual cases. Treatment and follow-up content is available in the app.