Recent research is finally shedding some light on a long-misunderstood symptom that occasionally plagues nearly everyone and constantly torments some: itching. New realizations about itching detailed in The New York Times are raising hopes that more effective treatments for itching may be attainable.
In one study published this past December, researchers caused volunteers’ arms to itch and then sent them through an MRI scanner to see what parts of their brain were activated during the itch and while scratching. They saw that itching activated a huge number of brain areas, including ones involved in motivation, reward, pleasure, craving and addiction. Many of these same regions were turned off when participants were able to scratch themselves, possibly explaining why it feels so good to scratch an itch.
However, this discovery suggests that there’s not just a single itch center that could be specifically targeted by one treatment. Itching, particularly chronic itching, has long been a difficult symptom to treat and has often been lumped in with pain treatment. But there are nerves and cellular receptors specific to itching and separate from pain, and in the past decade, research into itching as its own phenomenon has increased. In the past several years, itching research and treatment centers have opened for the first time in the U.S.
Current common treatments like cortisone creams and antihistamines may suffice for bug bites or temporary rashes, but they are often insufficient for people who suffer from chronic itching. Conditions like eczema, dry skin, psoriasis, kidney or liver failure, hormonal and nerve problems can all cause chronic itching that may become debilitating. While the temporary itching from bug bites is due mainly to the release of histamine, chronic itching can result from the release of other irritating substances and the activation of multiple types of nerve cells. These may provide new targets for therapy.
One such target may be a receptor in the spinal cord called gastrin-releasing peptide receptor (GRPR), which was found by a Washington University research team in 2007. The GRPR is specific for itching, and mice that lack the receptor did not appear to itch. Chronic itch often worsens with age, as other nerves that inhibit itching deteriorate. Studies of monkeys suggest that increased GRPR activity with age may also play a role. Researchers hope that one day a drug to block that receptor may alleviate chronic itch.