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Small Fiber Polyneuropathy: when insurers say no, reviewers often say yes
In 15 published external-review decisions involving small fiber polyneuropathy, independent physician reviewers overturned the insurer’s denial 80% of the time.
Published decisions
15
2001–2026
Overturned
80%
12 denials reversed
Most-fought treatments for small fiber polyneuropathy
What insurers denied — and how those fights ended.
What the insurer actually argued
Denials fall into different categories, and they don’t succeed equally — so the reason on your letter changes how you should answer it.
| Reason given | Decisions | Overturned |
|---|---|---|
Medical Necessity The plan said the care wasn’t medically necessary. The most common fight, and the most winnable. | 11 | 72.7% |
Experimental/Investigational The plan called the treatment unproven. These turn on published evidence, so the appeal is a literature argument. | 4 | 100% |
Typical time to a decision
7 days
Most land between 6 and 9 days
Handled as urgent
73.3%
Expedited when a delay would cause harm
What the reviewers wrote
Excerpts from the independent reviewers’ published findings — the actual reasoning, quoted, not summarised.
Where the denial was overturned
Nature of Statutory Criteria/Case Summary: An enrollee has requested authorization and coverage for IVIg Gammagard liquid 10% (37 grams every 2 weeks). Hovaguimian and Gibbons note that management of small-fiber neuropathy depends on the underlying etiology with concurrent treatment of associated neuropathic pain. Finnerup and colleagues report that inadequate response to drug treatments constitutes a substantial unmet need in patients with neuropathic pain. Liu and colleagues report evidence suggesting that intravenous immunoglobulin (IVIg) is safe and effective as a first-line treatment for patients with small-fiber-targeting autoimmune diseases akin to Guillain-Barré and chronic inflammatory demyelinating polyneuropathy.
Nature of Statutory Criteria/Case Summary: The patient has requested authorization and coverage for intravenous Panzyga [140 grams over five consecutive days (20 gm/30 gm/30 gm/30 gm/30 gm) followed by 60 grams over two consecutive days (30 gm/30 gm) monthly for six cycles]. Hovaguimian and Gibbons note that management of small-fiber neuropathy depends on the underlying etiology with concurrent treatment of associated neuropathic pain, which can include several different classes of medications. Colleagues report that inadequate response to drug treatments constitutes a substantial unmet need in patients with neuropathic pain.
Where the denial was upheld
Worth reading too — these show what an appeal has to overcome.
Nature of Statutory Criteria/Case Summary: The patient has requested authorization and coverage for Gamunex-C. Small fiber polyneuropathy occurs because of injury to the small unmyelinated C or thinly myelinated nerve fibers, and causes symptoms of numbness, sensory loss, electric shock-like pain, cold-like pain, itching, burning, tingling, and pins and needles feeling. The first line treatment for small fiber neuropathy includes tricyclic antidepressants (TCAs) such as amitriptyline, nortriptyline, and clomipramine, serotonin and norepinephrine reuptake inhibitors (SNRIs), and anticonvulsants such as duloxetine, gabapentin, and pregabalin. In this case, the patient was diagnosed with a small fiber neuropathy secondary to inflammatory or post-infection, with symptoms of tingling and burning pain in her extremities, sensitivity to cold temperature, and difficulty ambulating.
Nature of Statutory Criteria/Case Summary: The patient has requested authorization and coverage for Gammagard intravenous immunoglobulin (IVIG) (10%/120 grams, every four weeks). Liu and colleagues note that small fiber polyneuropathy has various underlying causes, including associations with systemic autoimmune conditions, while Morrison and Chaudhry note that a large number of medications and toxins may also produce neuropathy. Geerts and colleagues note that in the first double-blind, randomized, controlled trial evaluating the efficacy and safety of intravenous IVIG versus placebo in patients with idiopathic small fiber neuropathy, IVIG treatment had no significant effect on pain in patients with painful idiopathic small fiber neuropathy.
Figures and quotations on this page come from 42,749 published decisions in the California DMHC Independent Medical Review dataset. These are California outcomes — every state runs an equivalent external review, but the rates here are California’s. Excerpts are quoted verbatim from the public record and describe this condition generally, not any individual case.
How to use this in your appeal
These outcomes come from California’s external review program — an independent physician panel whose decision binds the insurer. Every state has an equivalent, and internal appeals succeed even more often. If your care for small fiber polyneuropathy was denied, the published record says the denial is worth fighting.
SOURCE: CALIFORNIA DMHC INDEPENDENT MEDICAL REVIEW OUTCOMES (CHHS OPEN DATA) · DERIVED AGGREGATE STATISTICS ONLY · METHODOLOGY
Not legal or medical advice. Coverage Rights is a self-help tool that helps you prepare your own appeal. For advice about your specific situation, talk to a licensed attorney or your doctor.