Itching and the Immune System

A study showed patients with chronic itching had immune system irregularities.

A chronic itching problem might seem like no big deal, even if it is a nuisance. There are indications, however, that it might signal a more serious problem.

A small study from the Center for the Study of Itch at Washington University School of Medicine in St. Louis found patients who suffered from chronic itching for no obvious reason also had immune system irregularities.

Chronic idiopathic pruritus is the medical term for chronic itching that has no obvious cause. It often accompanies conditions like renal failure, and can be distressing for the patient. Treatments usually include antihistamines, creams and lotions, but these manage symptoms rather than resolving the problem.

“As doctors, we throw things like antihistamines, ointments and lotions at patients who suffer chronic itching, but if there is something profoundly abnormal about the immune system—as it appears there is—then we can’t solve the itching until we address those underlying causes,” lead investigator Brian S. Kim, MD, said in a press release.

Dr. Kim is an assistant professor of medicine in the Division of Dermatology.

The immune system is incredibly complex which makes it difficult and expensive to study. This small study included only four patients, but Dr. Kim noted he has seen similar findings in numerous patients in the course of his clinical work.

Led by Amy Xu, a medical student who works in Dr. Kim’s lab, researchers collected blood samples and skin biopsies from the four patients. The patients ranged in age from 75 to 90. All had chronic itching, but no other history of allergic disorders like eczema or even a rash.

Three of the four had high levels of a protein called IgE, which is a marker of inflammation and often seen in patients with allergies. Blood tests also showed other abnormalities.

“The itching may be caused by some sort of wear and tear on the immune system,” Xu said.

The study is too small to allow the scientists to draw firm conclusions and the team plans to develop a more extensive study using mice.

The study was published in the July issue of the Journal of the American Academy of Dermatology.

Funding for the study was provided by the National Institute of Arthritis and Musculoskeletal and Skin Diseases, the National Institute of Allergy and Infectious Disease Asthma and Allergic Diseases Research Center, Washington University School of Medicine and the American Skin Association.

None of the authors reported a conflict of interest.

Sources
Washington University School of Medicine in St. Louis, “Researchers identify immune system irregularities that may cause itching”
http://medicalxpress.com/news/2016-05-immune-irregularities.html
Journal of the American Academy of Dermatology, “Immune dysregulation underlies a subset of patients with chronic idiopathic pruritus”
http://www.jaad.org/article/S0190-9622(15)02503-7/abstract
American Journal of Clinical Dermatology, “Chronic Pruritus in the Absence of Specific Skin Disease: An Update on Pathophysiology, Diagnosis, and Therapy”
http://www.medscape.com/viewarticle/729938

Written by: Beth Greenwood, RN | Medically reviewed by: Dr. Robert Carlson, M.D.