CPC07: Erythromelalgia associated with small-fibre neuropathy

Livia Francine Soriano,¹ Sophie Stoneham² and Helen Lotery¹

¹University Hospital Southampton NHS Foundation Trust, Southampton, UK; and ²Portsmouth Hospitals University Trust, Portsmouth, UK

Erythromelalgia (EM) is characterized by a triad of recurrent redness, burning pain and warmth of the extremities. We present a case of EM associated with small-fibre neuropathy (SFN). A 25-year-old woman presented with a 2-year history of recurrent swelling, redness and burning pain on her extremities, face and earlobes. Each episode lasted between 10 min and 3 h. The episodes were exacerbated by heat, stress, prolonged standing and physical activity, and relieved by leg elevation and cooling. There was associated myalgia, fatigue, paraesthesia of the feet and 25 kg weight loss. The patient had persistently low mood and prolonged work absences. She suffered from migraines and her regular medications included imipramine, metoclopramide and sumatriptan. On examination, she had ill-defined erythematous patches on her hands, arms, knees and ankles, with oedema in some areas. Neurological examination of cranial and peripheral nerves was normal. In view of her symptoms and striking weight loss, she was reviewed by physicians in multiple medical specialities, including rheumatology, gastroenterology, haematology and immunology. Full blood count, liver function tests, renal profile, connective tissue disease screen, upper and lower gastrointestinal endoscopies, haematinics, blood film, lymphoma screen, tryptase, C1 esterase inhibitor levels, borrelia screen, cortisol and urine electrophoresis were normal. Skin biopsy showed normal histology and negative immunofluorescence. Following these investigations, we made a clinical diagnosis of EM. The patient was referred to the neurology team who performed nerve-conduction studies, which were normal, and genetic testing, which was negative for the common mutations associated with EM. The neurology team referred the patient to a specialist SFN unit, where a skin biopsy demonstrated a reduced intraepidermal nerve fibre density, consistent with SFN. The patient’s symptoms are now controlled with a combination of carbamazepine and duloxetine, under the care of the neurology team. SFN is a generalized peripheral neuropathy affecting the small nerve fibres abundantly present in mucosa and skin. Patients with SFN experience sensory symptoms such as burning, stinging and pain in the extremities, and/or autonomic symptoms. EM as a manifestation of SFN is not well recognized; however, it may present as a predominant SFN with disturbance of control of vascular tone. We present our case for dermatologists to be aware of this association and to consider neurology referral in patients who present with EM.