People with fibromyalgia experience near-constant widespread pain, their hands and feet ache, and they often feel exhausted and foggy-brained. Yet because there is no blood test, lab test or scan that can confirm fibromyalgia, many doctors are skeptical about its very existence and suspect the problem is “all in the patient’s head.”

Finally, that’s about to change—because researchers at last have discovered a surprising key to this confounding and debilitating condition. The problem isn’t in patients’ heads—it’s in the skin of their hands.


To understand the new research, you first need to understand some basics about circulation. After leaving the heart, oxygenated blood travels through arteries and then into arterioles (small arteries) before entering the tiny capillaries. Oxygen and nutrients leave the capillaries to get into the body’s tissues and cells, and waste enters the capillaries. The blood then enters venules (small veins) and then larger veins, ultimately traveling to the lungs so it can be reoxygenated and filtered. And the cycle constantly repeats.

But not all blood enters the capillaries. Some blood flows directly from arteries into veins via arteriole-venule (AV) shunts, valves that open and close to control the passage of blood. The valves respond to cues from the nervous system, mainly to regulate body temperature. When a person is too hot, the shunts close, forcing the blood into the skin’s capillaries, where the heat can leave the body. When a person is cold, the shunts open, allowing the blood to flow into the venules and conserving heat. The parts of the body where AV shunts are most plentiful are the cheeks, nose, soles of the feet and palms of the hands. The skin in those areas is different—smooth, hairless and noticeably more sensitive to heat and cold.


For the new study, researchers took small samples of skin from the palms of the hands of women with and without fibromyalgia. (Women are more than twice as likely to be diagnosed with fibromyalgia as men, and the hands are particularly painful in fibromyalgia sufferers.) Using special dyes, filters and lenses, the researchers closely examined many structures in the skin that are supplied by nerve fibers, including the AV shunts.

Startling finding: The number of AV shunts didn’t differ between the two groups, but their size did. In fact, the AV shunts in women with fibromyalgia were nearly four times larger and had roughly two to eight times as many nerve fibers as those in women without fibromyalgia. This most likely explains why cold exacerbates fibromyalgia symptoms…and it also leads to a compelling theory about the development of fibromyalgia pain and fatigue.

As mentioned before, the AV shunts open and close in response to temperature—but they also regulate blood flow to other tissues, including muscles, when increased blood flow is needed, such as during movement and exercise. If the AV shunts are unable to function properly due to the presence of excessive nerve fibers, the mismanaged blood flow could be the source of the widespread muscle pain, achiness, fatigue and cognitive problems that plague fibromyalgia patients. The researchers are now investigating why there are excess nerve fibers around the shunts. Study leader Frank L. Rice, PhD, explained, “The AV shunts are sites where sensory nerve fibers are intermingled with nerve fibers of the sympathetic nervous system, which is activated by stress. The excess nerves involve mostly the sensory fibers that might be proliferating in response to stress activation of the sympathetic fibers.”


Hopefully, this new information about fibromyalgia patients will lead to effective treatments…but in the meantime, it’s reassuring to know that there is a real pathology involved in the disorder.

Dr. Rice’s team is currently investigating whether men with fibromyalgia have a similar pathology to that discovered in women. Preliminary results indicate that women normally have more of the sensory fibers affiliated with the AV shunts, which may put them at greater risk of having excess fibers. Still, fibromyalgia is thought to be vastly underdiagnosed in men. According to recent research from the Mayo Clinic, 19 out of 20 men likely to have the disorder are not being properly diagnosed.

Bottom line: Male or female, if you have symptoms that suggest fibromyalgia and your doctor dismisses them, get a second opinion. To find a health-care provider who is experienced in detecting and treating this disorder, check the National Fibromyalgia Association online directory. For a wealth of information about fibromyalgia and Dr. Rice’s ongoing research, visit the Web site of Integrated Tissue Dynamics.