Spinal injections of a common anesthetic such as lidocaine may help treat the inflammatory skin disease psoriasis, according to a new pilot study.
Psoriasis is a chronic immune disease with predominantly skin lesions, occurring periodically with exacerbations and remissions.
Most people have a form called plaque psoriasis. Periodic red, scaly patches appear on the skin that may be itchy and painful.
Standard treatments are aimed at controlling inflammation-the most common are topical corticosteroids. For people with a more severe form of psoriasis, some options include light therapy and injectables that suppress the immune system.
In a new study, scientists from China tried a completely different approach: injections of lidocaine, a commonly used local anesthetic, to block the sensory nerves that transmit pain signals.
Case studies showed that psoriasis patients experienced significant symptom relief after epidural anesthesia during surgery, said lead researcher Honglin Wang of Shanghai Jiao Tong University School of Medicine.
This, he said, suggests that the nervous system may play a "key role" in the onset of psoriasis.
For the study, Wang's group recruited four patients with severe psoriasis. They all received epidural lidocaine, where a small, flexible tube is inserted into the lower back to deliver the drug to a fluid-filled space outside the spinal cord.
The researchers treated each patient up to four times over two to five months. As a result, the severity of their psoriasis decreased by 35 percent to 70 percent, according to a standard score that measures the degree of the disease.
The improvement was maintained for at least six months, according to the report published in the Journal of Investigative Dermatology.
Researchers also tried to figure out why lidocaine was beneficial. They induced a condition similar to psoriasis in laboratory rats and then treated some of them with lidocaine. It turned out that the animals had excessive growth of sensory nerves on the psoriasis-affected skin areas, and the lidocaine treatment reduced that growth. The drug also prevented nerve cells from releasing a protein called CGRP, which can contribute to inflammation.