Advances in understanding itching and scratching: a new era of targeted treatments [version 1; peer review: 2 approved]

Chronic itch is a significant health burden with few effective treatments. As such, itch researchers seek to understand the mechanisms behind itch and to find potential targets for treatment. The field of itch research is dynamic, and many advances have been made so far this decade. In particular, major steps forward include the identification of new peripheral and central itch mediators and modulators, the discovery of greater roles for immune cells and glia in itch transmission, and a focus on the brain processing of itching and scratching. Finally, several new therapeutic interventions for itch have shown success in clinical trials

Advances in understanding itching and scratching: a new era of targeted treatments [version 1; referees: 2 approved]

Chronic itch is a significant health burden with few effective treatments. As such, itch researchers seek to understand the mechanisms behind itch and to find potential targets for treatment. The field of itch research is dynamic, and many advances have been made so far this decade. In particular, major steps forward include the identification of new peripheral and central itch mediators and modulators, the discovery of greater roles for immune cells and glia in itch transmission, and a focus on the brain processing of itching and scratching. Finally, several new therapeutic interventions for itch have shown success in clinical trials

Brain mechanism of itch in atopic dermatitis and its possible alteration through non-invasive treatments

Atopic dermatitis (AD) is a common chronic skin disease that is characterized by intense pruritus and has high impairment of quality of life. AD is often described as “the itch that rashes, rather than the rash that itches”. Several studies suggest that mechanisms of central modulation play an important role in the development and maintenance of chronic itch. Therefore, treating the neurosensory aspects of itch is an important part in the management of chronic itch. However, little attention has been paid to the role of the central nervous system in the processing of itch in AD. Targeting itch-related anatomical structures in the brain with non-invasive treatments such as psychological interventions and transcranial Direct Current Stimulation (tDCS) could have an antipruritic effect in AD. Therefore, in this review article, we discuss the current progress in brain imaging research of itch, as well as the efficacy of non-invasive interventions for itch relief in this patient group

Increased systemic levels of centrally acting B-type Natriuretic Peptide are associated with chronic Itch of different types

B-Type natriuretic peptide (BNP) is an itch-selective neuropeptide that was shown to play a role in both histaminergic and non-histaminergic itch in mice. It was also shown that elevated serum BNP is linked to increased pruritus in non-diabetic hemodialysis patients. This study examined plasma BNP levels of 77 patients and N-Terminal pro-BNP (NT-proBNP) levels of 33 patients with differing types of chronic itch to see if BNP and NT-proBNP levels can correlate with itch severity. Plasma BNP and NT-proBNP levels of all itch patients correlated to itch NRS, and in particular for patients with Chronic Pruritus of Unknown Origin (CPUO). Based on this clinical observation, this study further showed that increasing pathophysiological levels of BNP in mice by IV or osmotic pump induced significant scratching. Additionally, pharmacological and ablation strategies determined that BNP acts centrally by activating the natriuretic peptide receptor A (NPRA) in the dorsal horn of the spinal cord. These data support that BNP and NT-proBNP levels are associated with chronic itch and may be used in clinical setting