Immune Study Scratches an Itch for Answers
By Martha Michael
For those who are suffering from an excessive itching sensation, it makes sense to feel that research so far has not been up to scratch. There is little information about causes, especially among the older population, and it’s left medical scientists scratching their heads.
Patients are often instructed to use ointments and creams or told to take antihistamines. But if those remedies aren’t working, they may actually be suffering because of an immune disorder, according to researchers at the Center for the Study of Itch at Washington University School of Medicine in St. Louis.
The Journal of the American Academy of Dermatology reports the results from a very small sampling of four patients between the ages of 75 and 90. Using blood samples and skin biopsies, researchers discovered dysfunctional immune systems, says Brian S. Kim, MD, an assistant professor of medicine in the Division of Dermatology.
The blood samples showed:
- High levels of the protein IgE
- Low levels of an immunoglobulin called IgG
- Low levels of CD8 T-cells (immune cells)
- High numbers of eosinophils
Though none of the patients had previously suffered from allergy symptoms, they had high levels of antibodies that fight infections. Eosinophils and IgE are often found in individuals with allergies.
The possibility that an immune disorder was overlooked in the past could be the fact that patients without rashes or other signs of allergies don’t usually get skin samples biopsied. Patients who present with idiopathic pruritis, or chronic itching with an unknown origin, there’s nothing evident to biopsy.
“We often see similarly high counts of eosinophils in patients with eczema, but the patients we studied didn’t have eczema,” Dr. Kim says. “They didn’t even have a rash. Only itching.”
It may be the effects of age on the immune system, according to Amy Xu, a medical student in Kim’s lab. But more research with bigger sample numbers are necessary, because there could be additional causes for the condition.
“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,” Dr. Kim says. “The immune system needs to be in balance, and we hope to find ways to restore that balance in patients with this very debilitating condition.”
The good news is that at the Center for the Study of Itch there are labs in place and a head start on research. That makes it a faster and easier process than if they were starting from scratch.