Neuroimmune interactions between itch neurons and skin microbes.

Itch is an unpleasant sensation that is encoded by specific sensory neurons called pruriceptors. Itch is associated with almost all skin diseases. Recent studies revealed that many itchy skin diseases are associated with microbiome dysbiosis. Pathogenic microbes secrete proteases and toxins to invade skin cells. Some microbial products can directly activate sensory neurons, while others activate the mammalian immune system and indirectly cause itch. In this review, we summarize the current knowledge on microbe-immune-neuron crosstalks and discuss their relevance in itchy skin diseases.