Alternative therapies may be necessary for chronic itch

Denver - When presented with a patient suffering from itching, dermatologists should consider treatments other than topical and oral medications, according to an expert who spoke at the 72nd Annual Meeting of the American Academy of Dermatology.

It's hard to tell people not to scratch an itch, says Gil Yosipovitch, M.D., of Temple University School of Medicine, Philadelphia, because when a healthy person does this, it rewards pleasure centers in the brain. In chronic patterns such as uremic itch, however, imaging research suggests that in addition to impacting the pleasure and motor centers, scratching creates an itch-producing trigger and activates the prefrontal cortex.

"Experts in addiction know that these are core areas involved in addiction," Dr. Yosipovitch says.

Physicians also must acknowledge that chronic itch contributes to sensitization of nerve fibers, he says. This hypersensitization phenomenon has been shown to respond to selective serotonin/norepinephrine inhibitors (SNRIs) such as mirtazapine. Other options include gabapentin and pregabalin, along with neurokinin-1 inhibitors.

The cognitive components of itch suggest clearly, however, that targeting these factors may help, through avenues that might include distraction, stress reduction and behavioral modifications, Dr. Yosipovitch says.

"In 10 years," he predicts, "we'll have excellent drugs. But we won't be able to abolish all itch."

In the case of a 25-year-old male patient with a severe traumatic brain injury whom Dr. Yosipovitch treated, the patient's recovery from a vegetative state coincided with development of severe, intractable pruritus. "He described it as feeling like 1,000 mosquitoes biting him," Dr. Yosipovitch says.

The itch resisted high doses of conventional drugs. Neurological exams revealed the patient had significant thalamic injury, he says.

"It suggested to me that this patient had a central neuropathic itch," Dr. Yosipovitch says. Similar phenomena have been reported in patients with multiple sclerosis and strokes, he notes.

To treat such patients, "We must be more open-minded to the possibility that there are some cases where we don't know" exactly where and how the itch originates. In such cases, he may prescribe very high drug doses. "Twenty-five mg of pregabalin won't work because in these patients, the neural system is overworking. I can go up - slowly - to 450 mg per day, or up to 3,600 mg per day of gabapentin." Dr. Yosipovitch says he may combine these drugs with mirtazapine.

Moreover, he got the 25-year-old patient enrolled into an oncologic study investigating healing touch.

"There was nothing to lose, because he'd been to so many centers, and I wasn't able to help him. Do I believe it's a magic treatment? No," Dr. Yosipovitch says. But it did significantly reduce the patient's symptoms, probably through stress reduction. Other patients have experienced similar relief through acupuncture, he says.

"I don't know how the mechanism works. But if it works, I don't say no to it," he says.