How to appeal an insurance denial for rare disease.

A denial letter from your insurer means the plan has decided a treatment, medication, or service is not covered under your current policy. For rare disease patients, denials typically fall into one of four categories: not medically necessary (the most common), experimental or investigational, not covered under your plan, or step therapy not completed.

The denial itself is not a final answer. Under the Affordable Care Act, all health plans sold in the US are required to offer an internal appeals process. Studies consistently show that patients who appeal have a high rate of success — but most patients never appeal at all.

Your Explanation of Benefits (EOB) contains the specific denial reason code. This is the most important document in the appeal process. The denial reason determines what evidence you need.

Look for: the specific reason for denial (not just "not medically necessary" but the exact policy language used), the deadline to file an appeal, the name and contact information for the appeals department, and any reference to the policy section used to justify the denial.

If the letter doesn't include these details, call the member services number on your insurance card and ask for a written explanation that includes the specific clinical criteria used. You are entitled to this under federal law.

Every insurer publishes coverage determination policies — also called medical policies or clinical coverage guidelines — for each treatment category. These are usually available on your insurer's website by searching for the treatment name plus "clinical policy" or "coverage guidelines."

This document is critical because it tells you exactly what criteria your insurer uses to approve the treatment. If your doctor's documentation meets those criteria, your appeal can quote the insurer's own policy language back to them — which is far more persuasive than citing external evidence alone.

For rare disease denials, the medical literature is your strongest tool. PubMed is the public database of peer-reviewed medical research and is free to search. Look for systematic reviews and meta-analyses, and clinical practice guidelines from condition-specific organizations such as The Ehlers-Danlos Society, Dysautonomia International, and The Mastocytosis Society.

For rare diseases, case series and expert consensus guidelines are often the best available evidence — this is normal and accepted in appeal decisions. Your appeal should acknowledge the limited evidence base while citing the strongest available support.

A letter of medical necessity (LMN) from your treating physician is required for almost every appeal. Ask your doctor to include: your diagnosis and its clinical basis, why the denied treatment is appropriate for your specific presentation, why alternatives are not appropriate for you, the expected outcome of the treatment, and references to peer-reviewed clinical evidence.

A generic "this patient needs this medication" letter will not move the argument. A letter that addresses your insurer's specific denial criteria by name — ideally using the insurer's own policy language — is significantly more effective.

Your appeal letter should open with a clear statement of what you are appealing and what outcome you are requesting. Then address the denial reason directly — don't ignore it or work around it, engage with it point by point.

The structure that works: (1) state the denial you are appealing, including the denial date and reference number, (2) explain why the denial reason does not apply to your case using the insurer's own policy criteria, (3) present your clinical evidence with specific citations, (4) attach the letter of medical necessity and relevant records, (5) state clearly what you are asking for.

Submit via certified mail or through your insurer's secure online portal if available. Keep a copy of everything.

Under the ACA, you have the right to an external review by an independent review organization (IRO). The IRO's decision is binding on the insurer. Request external review within 60 days of receiving your internal appeal denial.

Other escalation paths: file a complaint with your state insurance commissioner, contact your state's Consumer Assistance Program, or — for employer-sponsored plans — contact the US Department of Labor's Employee Benefits Security Administration (EBSA).

For EDS: physical therapy, IVIG, and pain management medications are commonly denied. Cite clinical practice guidelines from The Ehlers-Danlos Society and published case series on the effectiveness of the specific treatment.

For POTS: beta blockers, fludrocortisone, and midodrine are commonly denied as "not medically necessary." Cite the 2015 Heart Rhythm Society Expert Consensus Statement by Sheldon et al., which established diagnostic criteria and treatment recommendations for POTS, IST, and vasovagal syncope.

For MCAS: mast cell stabilizers and epinephrine auto-injectors are sometimes denied. The Mastocytosis Society's diagnostic and treatment consensus papers are the strongest citations available.