Cell: Acute itching in eczema patients is associated with environmental allergens

January 15, 2021 /--- In addition to the rash, many eczema sufferers also experience chronic itching, but sometimes itching can become painful.
, standard antihistamines, which treat itching and allergies, usually don't work.
in a new study, researchers at the University of Washington's St. Louis School of Medicine and other researchers found that allergens in the environment are often to blame for acute itching episodes in eczema patients, and that this itching usually does not respond to histamines because itching signals are transmitted to the brain through a previously unrecoced pathway that current drugs do not target.
new findings point to a potential new target and strategy to help eczema patients cope with those episodes of acute severe itching.
results were published online January 14, 2021 in the journal Cell, under the title "A basophil-neuronal axis promotes itch".
from Cell, 2021, doi:10.1016/j.cell.2020.12.033. "Years ago, we thought that itching and pain were spread along the same path from nerve to brain, but that's not the case, and these new findings suggest that there's a different way to cause these acute itching episodes in eczema patients," said Dr. Brian S. Kim, co-author of the
paper and an associate professor of medicine at the University of Washington's St. Louis School of Medicine.
this itch can be crazy.
patients may rate their chronic itching at about 5 out of 10, but rise to 10 points during an acute itching episode.
we know that these acute itching episodes spread in a completely different way, we can target this pathway, and maybe we can help these patients.
typical way for eczema patients to have itching attacks is when cells in the skin are activated and histamines are released, while antihistamines inhibit histamines.
in this acute itching, another cell in the blood transmits itching signals to the nerves.
these cells produce too many other nonhistamines that cause itching;
, "We have linked acute itching in eczema patients to allergic reactions transmitted by completely different cell populations.
patients who experienced acute itching episodes had the same physical reactions as those with acute allergies.
if we can block this pathway with medication, it may represent a strategy that not only treats itching, but also other diseases, possibly including hay fever and asthma.
recent years, several clinical studies have tested a strategy involving blocking immunoglobulin E (IgE), a substance produced by the immune system against allergens.
allergy patients produce IgE, which causes allergic reactions, but its role in itching has been unclear.
reviewing clinical studies of drugs designed to treat chronic itching, Kim found a pattern in which patients reported episodes of acute itching, usually after exposure to environmental allergens.
also found that eczema patients with IgE, an allergen in the environment, were more likely to experience severe acute itching episodes.
explained, "Environmental allergens actually promote this type of itching.
such as eczema patients go to grandma's house, where there is a cat, the patient's itching will become very severe.
is likely that the cat's dander activates IgE, while IgE activates itching.
" Kim team took the observations to the lab, where his team developed a mouse model of eczema.
studying the mice, they found that when they produced IgE, they began to itch.
but unlike standard itching signals, cells in the skin called fat cells release histamines, and IgE in mice activates a type of white blood cell called alkaline granulocytes.
unlike nerve cells that carry itchy signals that respond to antihistamines, these alkaline granulocytes activate a completely different set of nerve cells.
found that acute itching in eczema is associated with exposure to allergens, which may help them avoid things that cause them to itch strongly, including animals, dust, mold, or certain foods.
, it also provides pharmaceutical companies with new targets for treating itching in eczema patients, including proteins and molecules identified by Kim's team along this newly discovered neural-immune path path.
(Bioon.com) Reference: 1. Fang Wang et al. A basophil-neuronal axis promotes itch. Cell, 2021, doi:10.1016/j.cell.2020.12.033.2.Acute itching in eczema patients linked to environmental allergens