Harlequin Syndrome

While working out at the gym one afternoon in August of 2008, Francis Lam began feeling “sweaty and hot, and — kinda weird,” as though there was a cool breeze blowing only on the right side of his face.  “I look over and see that there’s sweat dripping down my left arm,” remembers Lam, “and my right arm is somehow totally, totally dry.”

In the locker room afterward, Lam glanced in the mirror to find a bizarre reflection staring back at him: his face was flushed deep red and sweating profusely — but only on the left side. “I looked like the jester or something. There was literally a line down the middle of my face,” he recalls. His left arm, too, was sweaty and florid, while his right was dry and pale.

The startling nature of Lam’s normally healthy thirty-year-old reflection was a sign of Harlequin syndrome, a rare and poorly understood disorder of the nervous system.

The symptoms vary from one individual to the next, but always include the “Harlequin Sign,” where one side of the face doesn’t sweat or flush at all, a condition known as anhidrosis. The effect is extremely pronounced because the other half of the face compensates by sweating and flushing excessively — a condition called hyperhidrosis.

Harlequin syndrome is a result of damage to the autonomic nervous system, the “unconscious” part of the nervous system that controls the involuntary muscle contractions of organs, gland activities such as sweating and crying, and the fight-or-flight response. Nerves carry instructions for these actions to different parts of the body, so damage to a single nerve can result in loss of function at its destination.

However, like most diseases of the central nervous system, cases of Harlequin syndrome are almost always “idiopathic,” meaning doctors don’t know what causes the nerve damage, says Dr. Peter Drummond, a neurologist at Murdoch University in Australia who first described the syndrome in 1988. “Our best guess is that the nerves are being attacked by a virus, but we really don’t know,” says Dr. Drummond.

Lam’s case may be one of the few with a discernible cause — a cause whose story is as unlikely and, well, double-sided as the condition itself.

One evening a few months before discovering his Harlequin syndrome, Lam, who works as a food writer in New York, was mugged and beaten while walking home to his Queens apartment. A trip to the emergency room revealed a mild fracture in his eye socket, as well as something Lam hadn’t seen coming: a chest x-ray showed a large, solid mass in his torso, above his right lung.

Several weeks of doctors’ visits and tests resulted in a diagnosis: a tennis-ball sized “schwannomma” — a benign tumor growing off of the second nerve in his thoracic spine. It would have to be removed.

When Lam noticed his strange sweating pattern a few months before the surgery to remove the tumor, Lam called his neurologist, Dr. Mark Bilsky, at Sloan-Kettering Memorial Hospital in New York. Dr. Bilsky told Lam that the growth of the tumor may be at fault, but added that some damage to the sympathetic nervous system would almost certainly occur during surgery, anyway, because the system is so sensitive that “if you look at it the wrong way it’ll screw up.”

In the fall of 2008, Lam’s doctors managed to remove his tumor without damaging the nerves responsible for motor control in his hand — which were wrapped around the growth like twine on a package. But symptoms of Harlequin syndrome have persisted.

Though natural nerve regeneration is possible, says Dr. Drummond, nerves sometimes grow back in “haphazard ways” that have strange manifestations. Sometimes sweat nerves reconnect with salivary nerves, resulting in “gustatory sweating,” in which the brain’s instructions to salivate are mistranslated into instructions to sweat.

But how could a tumor in Lam’s chest have caused a sweating condition in his face and arm?

The connection, explains Dr. Martin Duddy, a neurologist at Newcastle upon Tyne in the United Kingdom, lies in the unique arrangement of the sympathetic nervous system. The system is linked together in a chain that starts in the brain, at the hypothalamus, and progresses down the spinal cord. Nerves split off from the spinal cord through small holes in the vertebra.

The nerves that travel to the face from the spinal cord “actually track all the way down into the chest cavity and then make their way back up to the face,” Dr. Duddy explains, emerging from the spine around the same vertebra where Lam’s tumor was growing. Dr. Drummond notes that tumors in that location can put pressure on nerves, pinching them like a kink in a hose or, if the tumor grows large enough, disrupting the nerve altogether.

Whether or not the symptoms of Harlequin syndrome diminish, Lam feels lucky to have sustained so little physical damage throughout his trauma. Though his good sense of humor keeps him from fretting too much about the disorder, he still seems somewhat baffled by the strangeness of it. “My left arm sweats a lot,” he says, “but then I only sweat on the right side of my torso. I’ll look down and see that my shirt is totally soaked in this perfect square, but then the other side of my shirt will be completely dry. It’s weird.”