Small fiber neuropathy: a common and important clinical disorder

The erythropoietin analog ARA 290 for treatment of sarcoidosis-induced chronic neuropathic pain

“…The pain in patients with chronic sarcoidosis is often related to neuropathy of the small fibers of the peripheral nervous system [2,3,12,13]. Small fiber neuropathy (SFN) is due to damage or loss of small myelinated (Ad-) and unmyelinated (C-) fibers of the sensory and autonomic nervous system [14,15]. SFN is a common manifestation in a variety of systemic disorders including diabetes mellitus, alcoholism, systemic amyloidosis, various autoimmune disorders (e.g., Sj€ ogren's disease, systemic lupus erythematosus), genetic disorders (e.g., Farbry's disease), infectious diseases (e.g., HIV infection) and may occur as part of a paraneoplastic syndrome [15].…”

“…Small fiber neuropathy (SFN) is due to damage or loss of small myelinated (Ad-) and unmyelinated (C-) fibers of the sensory and autonomic nervous system [14,15]. SFN is a common manifestation in a variety of systemic disorders including diabetes mellitus, alcoholism, systemic amyloidosis, various autoimmune disorders (e.g., Sj€ ogren's disease, systemic lupus erythematosus), genetic disorders (e.g., Farbry's disease), infectious diseases (e.g., HIV infection) and may occur as part of a paraneoplastic syndrome [15]. Most studies show that in just a minority of sarcoidosis cases a generalized large fiber neuropathy is observed [3,16].…”

“…The most prominent clinical features of SFN include pain (often described as burning or shooting), numbness, paresthesias, allodynia (causing intolerance to touch), and hyperalgesia [15]. In case of autonomic nerve involvement there …”

“…may be hypo/hyperhydrosis, diarrhea/constipation, sexual dysfunction, blurry vision, and orthostatic hypotension [14,15]. There is currently no specific treatment for sarcoidosis-related SFN.…”

“…Treatment of chronic pain with a neuropathic component using current treatment options (i.e., antidepressants, anticonvulsants, prolonged release opioids, and local applications) is not truly efficacious [4,5]. Small fiber neuropathy is a neuropathic pain disorder that is associated with a variety of diseases with worldwide a high frequency of occurrence (e.g., DM, leprosy, and HIV-infection) but also in other less common diseases (such as sarcoidosis) causing debilitating chronic pain and a significant reduction of the quality of life [15]. It is therefore not surprising that physicians and industry alike are actively searching for innovative treatment strategies that are distinct from the classical therapies (i.e., aimed at different pathways) [43].…”