The Similarities Between Fibromyalgia and Multiple Sclerosis

Some Cases May be Autoimmune, Dymyelinating

Is fibromyalgia more like multiple sclerosis (MS) than we thought? A unique line of research is making it look that way, at least in some cases.

To understand the research and what it means, first you have to understand a little about MS.

Illustration of nerve cells

Multiple Sclerosis Basics

MS is believed to be an autoimmune disease, which means the body's own immune system is going haywire and attacking a part of you, believing it's a pathogen and needs to be destroyed. In MS, the predominant theory is that symptoms are caused by something called demyelination, which means that the immune system is destroying something called myelin.

Myelin is a specialized cell that forms a sheath around some nerves and is necessary for those nerves to function properly. It's similar to insulation on electrical wires. Areas where the myelin sheath is destroyed are called lesions.

Fibromyalgia and Demyelination

The first study of fibromyalgia and demyelination came out in the journal Rheumatology in 2008, and the follow-up was published in a 2014 issue of Arthritis & Rheumatology.

The 2008 research suggested that a subset of fibromyalgia involved autoimmune demyelination and polyneuropathy (pain from damaged nerves). It compared fibromyalgia to a neurological illness called chronic inflammatory demyelinating polyneuropathy, which is often treated with intravenous immunoglobulin (IVIg).

In fact, in that study, they used IVIg to treat people from this fibromyalgia subgroup. Granted, it was a small study and only 15 people were treated, but researchers say those people had significantly less pain and tenderness plus improved strength, along with smaller improvements in fatigue and stiffness.

This is a good example of how a preliminary study can have seemingly huge implications and yet have little or no impact. Yes, some doctors have used IVIg on patients, but it's far from a widespread treatment and demyelination in fibromyalgia is almost never discussed.

Fast forward six years, and at last, we have a follow-up study that appears to confirm the earlier findings as well as advancing them. It's also supported by other work that's been done in the past few years.

The Newer Findings

First, the researchers wanted to explore whether the demyelination of large fibers (bigger nerves), found in the earlier study, was caused by autoimmunity. Then, they wanted to explore small fiber neuropathy, which other studies have suggested is involved in fibromyalgia.

Small fiber neuropathy is painful damage to structures in the of the skin, organs, and the nerves that allow you to feel and help regulate automatic functions like heart rate and body temperature. Researchers were interested in this line of questioning because small fiber neuropathy is sometimes associated with demyelination lesions on large fibers.

They did find indicators of small fiber neuropathy, including diminished feeling in the lower legs. Also tested were multiple markers of immune activation and autoimmune activity.

They say they discovered high indicators of small fiber neuropathy, and therefore large fiber lesions, in the legs of people with fibromyalgia. They also found that these indicators, especially in the calf, appear to be linked to a marker of immune activation called interleukine-2R.

They concluded that small fiber neuropathy likely contributes to our pain and that some of our pain comes from immune-system activity, which may include autoimmunity.

Putting It in Context

This follow-up study comes at a time when the interest of the fibromyalgia research community appears to be shifting toward small fiber neuropathy, inflammation, and possibly autoimmunity. Taken in context, this work adds to the emerging picture that we do have damaged nerves after all, that our peripheral nervous systems are definitely involved, and that autoimmunity or another aspect of immunity is at work.

This was still a fairly small study, but the fact that it furthered earlier work and appears to gel with other recent findings could mean that it'll have a bigger impact than its predecessor. At the very least, it seems that this is a worthy line of study that should continue.

A study in Medical Science Monitor, also published in 2014, found that people with MS have significantly higher rates of fibromyalgia than the general population. That could shore up the argument for similarities in the underlying mechanisms at work.

A Word From Verywell

Learning that their condition is similar to MS could have real benefits for people with fibromyalgia. First, most people know what MS is and respect it as a serious condition. That could lead to better public acceptance plus more universal acceptance in the medical community. That, in turn, could lead to more research.

Second, it could provide a new avenue of treatment for fibromyalgia among medications established for MS.

The similarity makes sense since both conditions can involve flares and remissions and the symptoms are extremely similar. It's likely that we'll continue learning more about this topic and that exciting things may come of it.

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

By Adrienne Dellwo
Adrienne Dellwo is an experienced journalist who was diagnosed with fibromyalgia and has written extensively on the topic.