Diagnosing Small Fiber Neuropathy

Diagnoising small fiber neuropathy

You’ve probably been hearing and reading more about small fiber neuropathy. Doctorsare now diagnosing small fiber neuropathy in their office, by doing a 3 mm skin punch biopsy and sending the specimen to Therapath for determination of epidermal nerve fiber density. The procedure takes only 5 to 10 minutes to perform, there is little discomfort to the patient, and the biopsy site is covered by a band aid. The test is most useful in patients with symptoms or signs of neuropathy, who’s electrodiagnostic studies don’t show any abnormalities, as is the case in small fiber neuropathy.

Therapath is a company that offers expert, comprehensive and prompt neuropathology services, specifically muscle, nerve, epidermal nerve fiber, sweat gland nerve fiber and brain, tissue analysis (or studies) to hospitals, private practitioners, reference laboratories, pharmaceutical industry, and researchers throughout the United States and Canada (abroad).

The company is accredited by the American College of Pathology (CAP) and has an established reputation of offering quality specialized neuropathology services that most major teaching institutions are cutting back on, rather than growing into. Our medical directors are board certified in neuropathology.

Neuropathology and Neuromuscular Pathology services are available for both clinical and pre-clinical investigations of potential therapeutic agents, drug toxicity, and of nerve or muscle regeneration. The company has the ability to scale up from proof of concept studies to multiple centers Phase II/III trials.

The specific tests Therapath performs are:

1. Muscle biopsy studies: including routine histology, immunohistochemistry and enzyme histology, for diagnosis of muscular dystrophies, inflammatory myopathies such as dermatomyositis or Polymyositis, or other metabolic, toxic, or inherited muscle diseases and Electron Microscopy.

2. Nerve biopsy studies: including routine histology, teased fiber analysis, and immunohistochemistry for diagnosis of CIDP, vasculitic, demyelinating neuropathies, sarcoid or amyloid neuropathy and Electron Microscopy.

3. Skin biopsy studies for Epidermal Nerve Fiber Density and Sweat Gland Nerve Fiber Analysis.

4. Consultation:

• Brain and spinal cord tumor biopsy and resection specimens

• Non-neoplastic brain and spinal cord biopsy specimens

• Brain and spinal cord autopsy specimens, including dementias


• Licensed under CLIA (Clinical Laboratory Improvement Amendments)

• The Centers for Medicare & Medicaid Services (CMS) regulates all laboratory testing (except research) performed on humans in the U.S. through the Clinical Laboratory Improvement Amendments (CLIA). In total, CLIA covers approximately 225,000 laboratory entities.

• The CAP (College of American Pathologists) Laboratory Accreditation Program is an internationally recognized program. An accredited laboratory is one that is inspected by a private not-for-profit t accrediting organization and the laboratory has met the highest standards of excellence.

CONTACT Information:
545 West 45th Street
New York, New York 10036
Phone: 800-681-4338
to Visit the Therapath Web Site Click Here:

About the Author

LtCol Eugene B Richardson, USA (Retired) BA, MDiv, EdM, MS

Col Richardson has suffered with severe neuropathy for over 45 years. A 27 year military veteran and veteran of the Vietnam War, he was diagnosed with a progressive chronic peripheral neuropathy resulting in severe disability. This diagnosis has been confirmed as due to exposure to Agent Orange. It was not until 2010, 42 years after his exposure to Agent Orange, that his diagnosis was recognized by Veterans Affairs as service connected.

Author Archive Page


  1. Dear Col Richardson,
    Thank you for your service, and thank you for this website and the ability to comment and receive answers from you on various topics. I thought I had posted my question yesterday, but I don’t know if it went through, if it did, please forgive me for duplication.

    I have been dealing with neuropathic pain in arms, legs, hands and feet since 2006, after sustaining a TBI in a bicycle accident. It has not gone away…..Many tests were done in the first few years but nothing was conclusive per my doctor…..and I have had other health issues co-occurring (chronic pain issues due to carpal and cubital tunnel syndrome, arthritis in entire spine/knees/shoulders/foot, chronic headache, TMJ, tendonitis that wont resolve, etc) however, I was just looking back at old records on a patient portal site and came across a skin punch biopsy report from 2007 with findings that I have no recollection of my doctor (who I no longer see) providing to me, my PCP doesn’t remember receiving this either. The report reads:

    Morphometric quantitation of PGP9.5 immunolabeled epidermal nerve endings
    yielded a density of 415 neurites per square mm of skin surface area, at the
    91st centile for age, far above the normal range. Fragmentation of axons can
    contribute to unusually high numbers of neurites. The clinical significance of
    increased neurite counts has not been defined in the medical literature,
    although clinical experience links it with early axonopathy. This density can
    be monitored with future biopsies to evaluate disease progression or the
    effects of therapy.

    I would love to know your thoughts on this test result. Was this test result POSITIVE for Small Fiber Neuropathy? I cannot find anything in my online research for AXONOPATHY (indicated in test result verbiage).

    Thank you so much for your insight and assistance,

    1. Sandra: Our medical texts note that this test report is positive for neuropathy but they usually note a small fiber neuropathy and axonopathy means that it shows damage to the actual nerve or axon rather than to the myelin covering of the nerve. We recommend skin biopsy be done by this firm as they are very reliable. Please see the information at this article and if you want the skin biopsy to rule out SFN give the information to your doctor: Skin Biopsy for diagnosis of small fiber neuropathy http://neuropathyjournal.org/skin-biopsy/ In addition SFN if diagnosed is often treatable with IVIg as noted by an expert on the subject. I will send you an E mail direct with a copy of the article on IVIg for SFN.

  2. Please help me, Dr. Richardson. I’m so scared and desperate. I was diagnosed with SFN almost ten years ago in a very cursory exam by a local neurologist Who put my hands in and out of warm and cold water she told me I had SFN and that it was idiopathic. She didn’t give me any more information about the disease and as the years went by I sought help for many doctors in my area and was diagnosed with many many neurological diseases which have not proven to be true. I’ve never had pain in my feet, the pain started in my hands. They would burn, turn blotchy red and white. I would ice them. Over the years I’ve been diagnosed with IBS, cystitis cystica and severe osteoarthritis in my joints which is excruciatingly painful. My newest symptoms started in the last few weeks I wake up with small muscle cramps all simultaneous and all over my body. I’ll have one in my foot , One behind my knee, one under my armpit, One over the top of my ankle, one in my toes, one in my thigh or one in my hip. They make me wake up screaming. If I don’t move they get worse and worse but I’m afraid to move because it hurts so bad and there are too many to grab them all to squeeze and massage. Any vibration of my body seems to continue like almost a memory vibration long after the stimulus is removed: elevators, my car after the engine has been turned off, vibrating massage after my recliner has been turned off, sitting in a parked car near Highway 290 I could feel the vibration in the pavement. I would like to go to the Cleveland clinic to be admitted for testing but I don’t have the money. I found a neurologist here who will do the skin biopsies, and my dermatologist has offered to do the biopsy’s as well and send them in for testing but I’m afraid the results could be false positives or false negatives if the shipper doesn’t get them there in time. Have you any suggestions about whether I should have biopsies done here and shipped off for testing? I was told by the Cleveland clinic that if I was found to have SFN they would also do internal organ punch biopsies. I’m sorry this letter is so disjointed but it’s late at night and I can’t sleep because I’m afraid of the cramps. Please. I have a degree in forensic anthropology from the University of Texas. I’ve had a passionate interest in anatomy since I was a child but I am really stumped and I really need your input. Thank you in advance for your time and consideration.

  3. Hi I have CIDP but was also told told I have SFN but never got tested because my Dr doesn’t believe in the accuracy of the test. I suffered in 2007 from early January to late June wgen was told having CIDP relapse waited 1 month for IVIG by then losing my hearing. A loading dose of IVIG and 2 weeks of dose Prednisone fixed it. Now I feel a relapse of SFN or CIDP but January was told not CIDP but never said anything about SFN. Last year in 10 months lost 15 lbs without trying can’t seem to gain weight bowel problems digestive problem Autonomic symptoms of over heating. Toes are cold at around 23 C and fingertips as low as 21C. Was tested for Raynaud’s in 2007 don’t have. My Neurologist from Ottawa Canada and doesn’t believe in the SFN testing. I had a nerve biopsy in 2005 which was normal but was in remission at the time. Got CIDP in the Fall of 2004. Trying to find a Dr who believes in the SFN testing. Is there a lab in the Ottawa area my Family Dr can send me too?
    Please and Thank You
    Lost 2 brothers to Idiopathic Pulmonary Fibrosis. Gilles died in 1976 at 17 years old and Michel in 1986 at 16 years old. The youngest recepient of a single Lung transplant at the time. Anti rejection drug Cyclosporin gave him cancer which killed him. I have other medical problems this Neuropathy gut problems weight loss and other inflammatory issues.


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