Small fiber neuropathy: a disabling and underrecognized syndrome

To discuss cause, clinical manifestations, diagnostics, and treatment of small fiber neuropathy (SFN). The diagnosis is difficult and can be easily missed.

SFN causes high morbidity with disabling symptoms and impact on quality of life. Patients may benefit from being diagnosed with SFN, even if no underlying cause is identified and no specific treatment is yet available. Recently, genetic mutations as a possible cause of SFN were identified. Clinical diagnostic criteria have been proposed, but no gold standard exists, and each test has its limitations. The diagnosis requires a combination of typical symptoms, abnormal neurologic findings, and absence of large fiber involvement. Clinicians should be aware of overlapping symptoms of SFN and fibromyalgia. Treatment is often difficult, even when the underlying cause is identified and appropriately treated. Usually, only symptomatic relief of complaints is available.

Awareness of SFN and related symptoms is of great clinical relevance. Guidelines for appropriate diagnostic workup using a stepwise approach involving a combination of tests are warranted. Even if no treatment is available, patients may benefit from timely recognition of SFN.