Ask the Doctors

Dear Doctor: Will you please explain erythromelalgia? What can ease the pain other than pills? Why does it spread to my upper legs, and what makes it so crippling? And does it worsen with time?

Dear Reader: I'm so sorry to hear that you're suffering from this poorly understood and complex disease. For other readers, we should start by pointing out that the typical symptoms of erythromelalgia are red, hot and painful skin, typically affecting the legs or the arms. The feet are affected in about 90 percent of patients, while the hands are affected in only 25 percent. As in your case, the redness and extreme burning sensation can spread up the legs to the thighs.

Erythromelalgia is quite rare, affecting only 1 or 2 people per 100,000 every year. It's twice as common in women than men and has an average onset of occurrence at about age 55. The disease appears to have both a neurologic cause related to nerve dysfunction and a vascular cause. Even more rarely, a genetic cause -- related to abnormal nerve firing -- can play a role. Further, a Mayo Clinic study found that 50 percent of patients with erythromelalgia had a history of smoking, so lifestyle may be a factor as well.

Episodes can last from minutes to days -- only about 3 percent of patients have continuous symptoms -- and are often precipitated by an increase in temperature or by exercise. For 25 percent of patients, the symptoms are worse at night. Of note, the pain completely subsides between episodes, so much so that in two-thirds of patients, the skin is cold to the touch and takes on a purplish appearance.

The condition is diagnosed by a patient's symptoms. There are no blood tests or skin biopsies that can help diagnose the disease.

Treatment often amounts to avoiding circumstances that can bring on the symptoms, such as heavy exercise and excessive heat. When episodes do occur, many people find benefit in spraying the skin with cold water and then using a fan to further cool the skin. Elevating the affected leg or arm can also ease symptoms. Note, however, that the skin should not be overly cooled, such as with ice, because that can damage the skin.

Lidocaine, used as an anesthetic ointment or patch, can provide some pain relief, as can topical medications that constrict blood flow, such as brimonidine and midodrine, and topical gabapentin, capsaicin and the anti-inflammatory diclofenac.

Aspirin can reduce both pain and episode frequency when erythromelalgia is associated with bone marrow disorders, but it also has shown benefit -- at 325 milligrams daily -- in preventing an episode. A few reports support the use of oral steroids, such as prednisone, during an outbreak.

Although you'd like to avoid pills, case reports suggest that medications used for nerve pain can decrease episodes. These include gabapentin, pregabalin, amitriptyline and venlafaxine. Carbamazepine and diltiazem have also been used to prevent outbreaks.

Lastly, we should add that the course of the disease is variable. In a study of 94 patients with erythromelalgia -- followed on average for 8.7 years -- 32 percent said their symptoms worsened over time, while 29 percent said their symptoms improved and 25 percent said their symptoms were unchanged. Only 11 percent had no recurrence of symptoms.

Please talk to your doctor about managing the condition with medication. The disease may be poorly understood, but that doesn't mean it's cause for hopelessness.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

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