SFN Pain Scale: Small Fibre Neuropathic Pain Scale
The SFN scale: a patient rated Small Fibre Neuropathic Pain Scale.
Small Fibre Neuropathy (SFN) is increasingly recognized as a cause of pain, especially burning pain. Small fiber neuropathy is linked to a number of different diseases, for instance diabetic neuropathy and CIAP, and often results in symptoms such as burning or stinging pain, shooting pain, and numbness. It can also manifest itself as an idiopathic neuropathic pain state.
The institute for Neuropathic Pain developed a prototype scale for patients, to quickly assess the likelihood of a SFN as the cause of pain.(SFN Scale: DOI: 10.13140/RG.2.2.22057.19046.) The scale is brief and quick to complete (a < 1 minute scale).
This patient-rated SFN scale is based on the well known and validated DN4 scale for neuropathic pain. The SFN scale consists of only 6 items and can be scored within a minute by patients. 5 of the 6 items are based on the DN4, one item adds muscle cramps to itch as a SFN symptom. Muscle cramps seem to occur in more than half of all patients suffering from SFN. 
The scale can be downloaded as PDF: SFN-INP-scale
The scale is currently under validation. However, as the scale is so easy to use, the INP published the scale in advance for patients to help them to more clarity in case of pain and neuropathy.
We developed this scale to assist the further developmental work in the field of the patent protected topical phenytoin cream.
Scores of scale leading to: High Chance, Moderate Chance and Low Chance on SFN pain
Keppel Hesselink JM. A prototype patent-rated Small Fibre Neuropathic Pain Scale. Institute Neuropathic Pain, 27 February 2017, DOI: 10.13140/RG.2.2.22057.19046.
February 2017, Jan M. Keppel Hesselink, MD, PhD
 Lopate G1, Streif E, Harms M, Weihl C, Pestronk A. | Cramps and small-fiber neuropathy. | Muscle Nerve. | 2013 Aug;48(2):252-5. doi: 10.1002/mus.23757. Epub 2013 Jun 28.