Table 1

Causes of small fibre neuropathy


Primary	Secondary
Idiopathic ▸ Idiopathic small fibre neuropathy ▸ Burning mouth syndrome	Metabolic ▸ Impaired glucose tolerance ▸ Diabetes mellitus ▸ Rapid glycaemic control ▸ Vitamin B12 deficiency ▸ Dyslipidaemia ▸ Hypothyroidism ▸ Chronic kidney disease
Hereditary/genetic ▸ Na_v1.7 mutations ▸ Na_v1.8 mutations ▸ Familial amyloid polyneuropathy ▸ Fabry's disease ▸ Tangier's disease	Infections ▸ HIV ▸ Hepatitis C ▸ Influenza
	Toxins and drugs ▸ Anti-retrovirals ▸ Antibiotics—metronidazole, nitrofurantoin, linezolid ▸ Chemotherapy—bortezomib ▸ Flecainide ▸ Statin ▸ Alcohol ▸ Vitamin B6 toxicity
	Immune mediated ▸ Coeliac disease ▸ Sarcoidosis ▸ Sjögren's syndrome ▸ Rheumatoid arthritis ▸ Systemic lupus erythematosus ▸ Vasculitis ▸ Inflammatory bowel disease ▸ Paraneoplastic ▸ Monoclonal gammopathy/amyloid

Note that a number of these conditions may present as a small fibre neuropathy and then evolve to include large fibres.