Erythromelalgia in Adult
See also in: Cellulitis DDxAlerts and Notices
Synopsis
Erythromelalgia may be primary or secondary, with primary erythromelalgia (PE) further separated by some into a primary inherited form and an idiopathic group. Others consider only the inherited form as PE. This primary inherited form is due to an autosomal dominant mutation in the SCN9A gene on chromosome 2q that encodes for Nav 1.7 (voltage-gated sodium channels present in small nociceptive neurons). By contrast, secondary erythromelalgia can be associated with a multitude of underlying conditions. These include myeloproliferative disorders with thrombocythemia, in addition to vascular, connective tissue, neurological, and musculoskeletal conditions. Some drug reactions have been reported to trigger erythromelalgia, as have poisonings and intoxications.
Poisoning from ingestion of the mushroom Paralepistopsis (formerly Clitocybe) acromelalga causes a self-limited form of erythromelalgia. Onset is within 2-3 days of ingestion, and symptoms usually resolve in 1-2 weeks but may persist for months.
Incidence estimates have ranged from 0.3 to 1.3/100 000 for all forms of erythromelalgia, and these are considered low due to underdiagnosis. Some studies suggest a female predominance of up to 2-3:1, and there does not appear to be a racial / ethnic predilection.
Codes
ICD10CM:I73.81 – Erythromelalgia
SNOMEDCT:
37151006 – Erythromelalgia
Look For
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Diagnostic Pearls
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Differential Diagnosis & Pitfalls
- Raynaud phenomenon – triggered by cold
- Reflex sympathetic dystrophy – more continuous, unilateral, and worsened by cold
- Fabry disease – X-linked alpha-galactosidase deficiency on laboratory testing
- Peripheral neuropathy – primarily sensation changes
- Multiple sclerosis – intermittent dysesthesia may be a symptom
- Cellulitis – localized and not chronically intermittent
- Angioedema – urticarial swelling, lacks burning sensation
- Vasculitis – purpuric presentation
- Acral erythema – palmoplantar eruption seen with chemotherapy
- Frostbite – episodic with history of cold exposure
- Contact dermatitis – scaling erythema with pruritus
- Eosinophilic cellulitis – sudden urticarial plaques, pruritic to painful
- Tinea pedis – erythema with pruritus and scaling noted
Best Tests
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Management Pearls
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Therapy
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Drug Reaction Data
Below is a list of drugs with literature evidence indicating an adverse association with this diagnosis. The list is continually updated through ongoing research and new medication approvals. Click on Citations to sort by number of citations or click on Medication to sort the medications alphabetically.Subscription Required
References
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Last Reviewed:10/24/2022
Last Updated:11/09/2022
Last Updated:11/09/2022