(Press-News.org) In addition to a skin rash, many eczema sufferers also experience chronic itching, but sometimes that itching can become torturous. Worse, antihistamines -- the standard treatment for itching and allergy -- often don't help.
New research from Washington University School of Medicine in St. Louis indicates that allergens in the environment often are to blame for episodes of acute itch in eczema patients, and that the itching often doesn't respond to antihistamines because the itch signals are being carried to the brain along a previously unrecognized pathway that current drugs don't target.
The new findings, published Jan. 14 in the journal Cell, point to a possible new target and strategy to help eczema patients cope with those episodes of acute, severe itch.
"Years ago, we used to think that itch and pain were carried along the same subway lines in the nerves to the brain, but it turned out they weren't, and these new findings show there's another pathway entirely that's causing these episodes of acute itching in eczema patients," said principal investigator Brian S. Kim, MD, a dermatologist and an associate professor of medicine. "The itch can be maddening. Patients may rate their chronic itch at around a 5 on a scale of 10, but that goes up to 10 during acute itch flares. Now that we know those acute flares are being transmitted in an entirely different way, we can target that pathway, and maybe we can help those patients."
The typical pathway for itching in eczema patients involves cells in the skin that are activated and then release histamine, which can be inhibited with antihistamine drugs. But with this acute itching, a different type of cell in the bloodstream transmits itch signals to the nerves. Those cells produce too much of another non-histamine substance that triggers itch; therefore, antihistamines don't work in response to such signals.
"We've connected acute itching in eczema to allergic reactions transmitted by an entirely different population of cells," said Kim, also the co-director of the Center for the Study of Itch & Sensory Disorders. "In patients who experience episodes of acute itching, their bodies react in the same way as in people with acute allergy. If we can block this pathway with drugs, it might represent a strategy for treating not only itch but other problems, including perhaps hay fever and asthma."
In recent years, several clinical studies have tested a strategy that involves blocking Immunoglobulin E (IgE), a substance produced by the immune system in response to allergens. Patients with allergies produce IgE, causing allergic reactions, but its role in itch has been unclear.
Reviewing data from clinical studies of drugs aimed at treating chronic itching, Kim found a pattern in which patients reported episodes of acute itching, often after exposure to environmental allergens. He also found that eczema patients who make IgE in response to allergens in the environment were more likely to experience those episodes of severe, acute itch.
"Environmental allergens actually promote this type of itch," he explained. "Say a patient with eczema goes to Grandma's house, where there's a cat, and that person's itching just goes crazy. It's likely cat dander is activating IgE, and IgE is activating itch."
Kim's team took these observations to the laboratory, where his team made a mouse model of eczema. Studying the animals, they found that when the mice made IgE, they began to itch. But unlike standard itch signals, in which cells in the skin called mast cells release histamine, the IgE in mice with eczema activated a type of white blood cell called a basophil. Those cells then activated an entirely different set of nerve cells than the cells that carry itch signals that respond to antihistamines.
The discovery that acute itching in eczema is linked to exposure to allergens may help them avoid things that make them itch intensely, including animals, dust, mold or certain foods. Meanwhile, it also offers drug companies new targets for treating itch in eczema patients, including proteins and molecules Kim's team has identified along this newly identified neuro-immune pathway.
INFORMATION:
Kim BS, et al. A basophil-neuronal axis promotes itch. Cell, Jan. 14, 2021.
This work was supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases and the National Institute of Allergy and Infectious Diseases of the National Institutes of Health (NIH). Grant number K08 AR065577, R01 AR070166, R01 AR065577, R01 AR070873, R01 AI077600, t32 AI716339f and F30 AI154912-01. Additional support from the American Skin Association, the Doris Duke Charitable Foundation, LEO Pharma,
Washington University School of Medicine's 1,500 faculty physicians also are the medical staff of Barnes-Jewish and St. Louis Children's hospitals. The School of Medicine is a leader in medical research, teaching and patient care, ranking among the top 10 medical schools in the nation by U.S. News & World Report. Through its affiliations with Barnes-Jewish and St. Louis Children's hospitals, the School of Medicine is linked to BJC HealthCare.
The sun is the only star in our system. But many of the points of light in our night sky are not as lonely. By some estimates, more than three-quarters of all stars exist as binaries -- with one companion -- or in even more complex relationships. Stars in close quarters can have dramatic impacts on their neighbors. They can strip material from one another, merge or twist each other's movements through the cosmos.
And sometimes those changes unfold over the course of a few generations.
That is what a team of astronomers from the University of Washington, Western Washington University and the University ...
There's a 7-fold unexplained variation in rates of euthanasia across The Netherlands, reveals an analysis of health insurance claims data, published online in the journal BMJ Supportive & Palliative Care.
It's not clear if these differences relate to underuse, overuse, or even misuse, say the researchers.
The Netherlands was the first country in the world to legalise euthanasia and physician-assisted suicide, introducing preliminary legislation in 1994, followed by a fully fledged law in 2002. The practice has been tolerated, however, since 1985.
Official data show that the number of euthanasia cases has risen more or less continuously since 2006, reaching 6361 in 2019. These cases ...
Climate change impacts, affecting primarily ecosystems' functions and consequently human sectors, have become a crucial topic. Observed and expected variations in climate conditions can in fact undermine the ecosystems' ecological equilibrium: average climate patterns, mainly represented by intra-annual (monthly to seasonal) temperature and precipitation cycle, directly influence the distribution, abundance and interactions of biological species.
During the long history of scientific research on the relationships between climate and Earth's communities, ...
BIRMINGHAM, Ala. - Use of the diabetes drug metformin -- before a diagnosis of COVID-19 -- is associated with a threefold decrease in mortality in COVID-19 patients with Type 2 diabetes, according to a racially diverse study at the University of Alabama at Birmingham. Diabetes is a significant comorbidity for COVID-19.
"This beneficial effect remained, even after correcting for age, sex, race, obesity, and hypertension or chronic kidney disease and heart failure," said Anath Shalev, M.D., director of UAB's Comprehensive Diabetes Center and leader of the study.
"Since similar results have now been obtained in different populations from around the world -- including China, France and a UnitedHealthcare analysis -- this suggests that the ...
Ignoring a colleague's greeting or making a sarcastic comment in the workplace may actually do more harm than intended, according to West Virginia University research.
Perceived low-grade forms of workplace mistreatment, such as avoiding eye contact or excluding a coworker from conversation, can amplify suicidal thoughts in employees with mood disorders, based on a study by Kayla Follmer, assistant professor of management, and Jake Follmer, assistant professor of educational psychology.
"We know from prior research that minor forms of workplace mistreatment reduce employee engagement," Kayla Follmer said. "But our paper provided an explanation for ...
New York, NY (January 14, 2020) -- Girls who are emotionally neglected or severely sexually abused early in their lives report riskier sexual behaviors during adolescence, Mount Sinai researchers report. The findings highlight the need--and suggest the potential for tailored approaches--to promote healthy sexual development in vulnerable populations.
The researchers identified four distinct patterns of neglect and sexual abuse in low-income, predominantly Black and/or Latina girls and young women that led to distinct trajectories of risky sexual behavior during adolescence. Their findings were published in Child Development in January.
The study was the first of its kind to identify categories of maltreatment among adolescent girls of color in an urban setting that correspond with measurable ...
The COVID-19 pandemic, which claimed more than 336,000 lives in the United States in 2020, has significantly affected life expectancy, USC and Princeton researchers have found.
The researchers project that, due to the pandemic deaths last year, life expectancy at birth for Americans will shorten by 1.13 years to 77.48 years, according to their study published Thursday in the Proceedings of the National Academy of Sciences.
That is the largest single-year decline in life expectancy in at least 40 years and is the lowest life expectancy estimated since ...
A team of biophysicists from the University of Massachusetts Amherst and Penn State College of Medicine set out to tackle the long-standing question about the nature of force generation by myosin, the molecular motor responsible for muscle contraction and many other cellular processes. The key question they addressed - one of the most controversial topics in the field - was: how does myosin convert chemical energy, in the form of ATP, into mechanical work?
The answer revealed new details into how myosin, the engine of muscle and related motor proteins, transduces energy.
In the end, their unprecedented research, meticulously ...
Humans, mammals and birds that live in a particular environment share a common set of behavioral traits, according to a new study, which identifies a local convergence of foraging, reproductive and social behaviors across species. The findings, based on studying more than 300 small-scale human hunter-gatherer populations, support one of the central tenets of human behavioral ecology - that ecological forces select for various behaviors in distinct environments, driving behavioral diversity worldwide. The origin and evolution of human behavior are uncertain and debated. While some suggest ...
The volatile plant hormone ethylene allows plant roots to sense and avoid compacted soils, researchers report. Rendering roots insensitive to ethylene allowed them to penetrate compacted soils more effectively, the same group showed. The findings reveal how plants regulate their growth in response to soil compaction - a growing challenge facing modern agriculture worldwide - and could serve as a pathway for how breeders might select or develop new crops resilient to soil compaction. Driven in part by a growing reliance on heavy machinery and poor soil management practices, soil compaction can lead to declining crop yields by restricting root growth and limiting the availability ...
