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The Unsolved Mystery of Itching
July 01, 2008 2:50 PM
A case study of chronic itching leaves neurologists and researchers scratching for answers.
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A recent article in The New Yorker explored the bizarre, tragic story of a woman known as M who suffered from a mysterious, perpetual itching that baffled doctors. One night in her sleep, M scratched clear through to her brain.
A frustrated M, having been hospitalized, cuffed to a bed, and forced to wear a foam helmet, said, “They kept telling me I had O.C.D.” Psychiatrists continually asked questions like, “As a child, when you walked down the street did you count the lines?”
Neurologist Anne Louise Oaklander reassured M that she didn’t have OCD. Instead, Oaklander hypothesized that the condition was neurological.
In 1997, German and Swedish researchers discovered the nerve that signaled itching and established that it differed from receptors for pain. Still, M had lost almost all her nerve receptors. If nerves are responsible for our perceptions, why hadn’t the itch diminished?
Atul Gawande, the author of the New Yorker piece, explained in an NPR radio interview that people don’t feel pain from simply talking about putting their hands in a flame. However, describe an ant crawling up someone’s back and the listener will feel it. “There’s something more interesting to our perceptions than just the fact that you trigger a nerve, it goes up the spinal cord to your brain and it rings a bell in your brain,” Gawande said.
Gawande consulted V.S. Ramanchandran, who explored another mysterious sensory condition called “phantom limb pain.” Since 1995, Dr. V.S. Ramanchandran has used mirror boxes to treat patients with phantom limb pain.
Meanwhile, itching’s semipsychological nature can also be evidenced in its side effects: depression and fatigue.
A frustrated M, having been hospitalized, cuffed to a bed, and forced to wear a foam helmet, said, “They kept telling me I had O.C.D.” Psychiatrists continually asked questions like, “As a child, when you walked down the street did you count the lines?”
Neurologist Anne Louise Oaklander reassured M that she didn’t have OCD. Instead, Oaklander hypothesized that the condition was neurological.
In 1997, German and Swedish researchers discovered the nerve that signaled itching and established that it differed from receptors for pain. Still, M had lost almost all her nerve receptors. If nerves are responsible for our perceptions, why hadn’t the itch diminished?
Atul Gawande, the author of the New Yorker piece, explained in an NPR radio interview that people don’t feel pain from simply talking about putting their hands in a flame. However, describe an ant crawling up someone’s back and the listener will feel it. “There’s something more interesting to our perceptions than just the fact that you trigger a nerve, it goes up the spinal cord to your brain and it rings a bell in your brain,” Gawande said.
Gawande consulted V.S. Ramanchandran, who explored another mysterious sensory condition called “phantom limb pain.” Since 1995, Dr. V.S. Ramanchandran has used mirror boxes to treat patients with phantom limb pain.
Meanwhile, itching’s semipsychological nature can also be evidenced in its side effects: depression and fatigue.
Understanding the science of itching
According to The New Yorker, despite having lost 96 percent of the nerves on the scratched portion of her scalp, patient M continued to feel an itch. Gawande explained, “The mind integrates scattered, weak, rudimentary signals from a variety of sensory channels.” Richard Gregory, a neuropsychologist, calculated that “visual perception is more than ninety per cent memory and less than 10 per cent sensory nerve signals.”
Source: The New Yorker
In her 2007 report, Dr. Anne Louise Oaklander, an Assistant Neurologist and Neuropathologist at Massachusetts General Hospital and Assistant Professor at Harvard, documented the history of a 39 year-old patient (presumably patient M), indicating that some itches have “neurological causes.”
Source: Beeson
Audio: ‘The Mystery and Power of the Itch’
In an NPR interview New Yorker writer Atul Gawunde used the metaphor of a bell and clapper to conceptualize feeling a sensation such as M’s itching: “Here are cases where you don’t have the clapper and yet the bell continues to ring.”
Source: NPR
Background: Definition of an itch, effects of itching, mirror boxes
Gil Yosipovitch, MD, and Malcolm Greaves report, “The simple definition of itch first proposed by Samuel Hafenreffer (1660) 340 years ago as an ‘unpleasant sensation provoking the desire to scratch’ is still widely used, but as indicated by Savin (1998) it is unsatisfactory.” There are different types of itching, including neuropathic, neurogenic and psychogenic itches.
Source: Itch Forum
Depression and fatigue are common side effects of itching. According to Dr. Gil Yosipovich, of Wake Forest University Baptist Medical Center, patients with kidney failure who undergo dialysis often suffer from constant itching. He warns of a “17 percent higher rate of mortality” probably caused by fatigue.
Source: Chicago Tribune
In 1997, according to the New Scientist, German and Swedish researchers discovered a nerve that responded specifically to the sensation of being itched. Before this report, scientist believed the “itch message” was transferred by “slow pain receptors.” Scientists confessed they were still perplexed over which nerves sensed tickling.
Source: New Scientist
Dr. V.S. Ramanchandran created a treatment known as the mirror box—basically a cardboard box fitted with a mirror—which gave patients with phantom limbs, like Derek Steen, freedom from seemingly interminable pain.
Source: The New York Times (free registration may be required)
Related Topics: Other mystery diseases of the senses: Tinnitus and Morgellons
Like M’s mysterious itching disorder, the cause of Tinnitus, a chronic ringing in the ears, hasn’t yet been established. Some scientists believe the problem is related to damaged hair cells in the inner ear.
Source: Time
A 2006 Time magazine article explored Morgellons, a disease that hasn’t been discussed in medical texts since 1674. Time writer Paige Bowers writes, “Some have suggested that it is a hoax, even a viral marketing campaign for a sci-fi movie. But sufferers say it's real and that there have been a growing number of cases across the nation of people with these painful fibers, skin lesions, crippling fatigue and memory loss.
Source: Time
© 2008 Dulcinea Media, Inc.
