Abstract and Introduction
Chronic prurigo is a distinct disease defined by the presence of chronic pruritus for at least 6 weeks, a history and/or signs of repeated scratching, and multiple localized or generalized pruritic skin lesions (whitish or pinkish papules, nodules and/or plaques). Although chronic prurigo is frequently named prurigo nodularis, the nodular type of chronic prurigo is only the main clinical aspect of chronic prurigo. Chronic prurigo occurs due to neural sensitization to pruritus and the development of a vicious pruritus–scratching cycle. Chronic prurigo can be of allergological, dermatological, systemic, neurological, psychiatric/psychosomatic, mixed or undetermined origin. The prevalence is still debated. The burden is high. Current treatments often remained disappointing. Fortunately, recent research results on the pathophysiology of pruritus evidenced neuroimmune interactions and allow new therapeutic perspectives. Among them, antagonists of T-helper 2 cytokines, κ-opioids and Janus kinase inhibitors may be promising.
Pruritus (or itch) is defined as an unpleasant sensation that evokes a need to scratch and is considered as chronic beyond 6 weeks.[1–6] Research on itch has been very dynamic for 25 years, and has provided significant advances to start deciphering the molecular and cellular mechanisms underlying itch sensation in the skin and in the peripheral and central nervous systems, allowing hopes for new treatments in the coming years. Although prurigo is not the only clinical manifestation of chronic pruritus, therapeutic trials of antipruritic drugs are focused on chronic prurigo, especially nodular prurigo, because chronic prurigo, as both a cause and consequence of pruritus, is the model of chronic pruritus.
This review summarizes the recent discussions on the definition and clinical aspects before approaching epidemiology, pathogenesis and consequences and then identifies therapeutic targets and emerging treatments.
The British Journal of Dermatology. 2022;187(4):464-47. © 2022 Blackwell Publishing