Increased understanding of itch leading to better treatments

Itching is the most common complaint among patients with inflammatory skin disease, ranking near lower back pain as a leading complaint overall among patients. Despite that ranking and an increased understanding of the causes of itch, much more needs to be learned by researchers and clinical dermatologists, so the Academy has made pruritis one of its top research priorities.

A March 24 session, “Chronic Pruritus: Bedside to Bench Perspectives” (S042), will use a mix of basic science and clinical presentations to explain the expanding understanding of itch and how that is being translated into new treatments.

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Gil Yosipovitch, MD

“There is an unmet need regarding itch that the Academy identified a couple of years ago. Very few of us address this in a comprehensive fashion,” said Gil Yosipovitch, MD, the course director. “We address it as part of disease states, but itch itself is a major problem that affects the quality of life of our patients.

“The field has grown significantly and the science has been revolutionized in the last decade. We know a lot more, but it has to be translated to understanding treatments, identifying the core problems, and how to address them.”

Those advances are being driven by the scientific communities in dermatology and neuroscience, who have learned about itch pathways and signaling systems, said Timothy G. Berger, MD, co-director of the course.

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Timothy G. Berger, MD

“This is an immunologic and neurologic process. Something happens to the skin that gets communicated to a nerve, and that is perceived as itching,” said Dr. Berger, clinical professor of dermatology at the University of California, San Francisco. “We do have new paradigm-changing concepts of treatment that have changed the way a lot of us who have managed itch approach the problem. This session is to update dermatologists on this new knowledge in the clinical and scientific aspects of itch, but also make them aware of these new treatment approaches.”

Seven speakers will address four areas: the basics of itch, itching related to atopic dermatitis and eczema, neuropathic itch, and itch in the elderly. A focus of the first two areas is clarifying the effect of itch on quality of life, which will include video interviews with patients discussing how itch affects them.

“Part of what we want to convey is that having itch is really life-altering, and that has been underappreciated,” Dr. Berger said. “I think dermatologists understand this, but I think that physicians in general and patient support networks have really not provided the compassion they should for the amount of suffering patients have. If you itch terribly, you don’t sleep, and if you don’t sleep, then your quality of life is terrible.”

Chronic itch is linked to a hypersensitization phenomenon of nerve fibers, which makes the nerves valid targets for treatment, said Dr. Yosipovitch, professor and chair, department of dermatology and director of the TempleItchCenter, Temple University School of Medicine, Philadelphia.

“We will discuss drugs that work on this pathway of sensitization of nerve fibers,” he said. “A good example is gabapentin and pregabalin, which are drugs that do work for chronic pain and chronic itch. A combination of them with some antidepressant drugs enables us to reduce that sensitization.”

Another target for treating chronic itch is the mu receptor — the receptor for morphine drugs and a known cause of itch.

“Now, we have drugs that mitigate this effect, such as kappa agonists. This field is evolving into treatments,” Dr. Yosipovitch said.

The geriatric population is disproportionately affected by severe itch. One in five visits to the medical system by Asian men is for itching, Dr. Berger said, adding that he will discuss the pathogenic basis for this complaint, and how to manage it.

“We are not covering all the topics of itch, but we are identifying areas we think are important for dermatologists to better understand,” Dr. Yosipovitch said. “The bottom line is to increase understanding and awareness. We understand there is an unmet need to better treat our patients with chronic itch.”

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