Restless legs syndrome (RLS) is characterized by an unpleasant discomfort that is perceived in the legs (and occasionally the arms) and felt to decrease when patients move their limbs. This relief is, however, usually temporary, as patients feel the need to continually move their limbs. RLS disrupts sleep as a result, causing fatigue that may affect many aspects of a patient’s life.

As many as 12 million Americans are estimated to have RLS, according to the National Institutes of Health. Many experts believe that this disorder is underdiagnosed and that the prevalence may be higher.

Patients often report leg discomfort that is described as creeping, crawling, pulling, itching, tingling, burning, aching or painful sensations. Others perceive it as arising deep within their legs. There are two major types of RLS:

• Primary restless legs syndrome. This results from unknown factors. In most cases, primary RLS is a lifelong condition that can progress over time.
  
  
• Secondary restless legs syndrome. This form results from an underlying condition, such as pregnancy, fibromyalgia or diabetes, or is a side effect from certain medications. Symptoms typically subside if the source of the disorder is resolved.

More than 80 percent of people with RLS also have an associated condition known as periodic limb movement disorder, in which a person’s leg involuntarily twitches or jerks excessively for anywhere from 10 seconds to a full minute.

Women are at greater risk of developing RLS than men. The incidence increases as people age, with many diagnosed sometime during middle age.

At present, no test can definitively detect RLS. Diagnosis is typically based on the patient’s symptoms after other possible causes are ruled out.

Patients with RLS can often find relief by making certain lifestyle changes. More severe cases may require medication. The U.S. Food and Drug Administration has approved two anticonvulsant drugs to treat RLS.