Chronic prurigo.

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. What is already known about this topic? Chronic prurigo or prurigo nodularis is poorly known by dermatologists and the definition was rather vague until recently. What does this study add? This review provides a summary of the recent developments of nosology and research (from basic research to epidemiology and clinical research), and current and near-future management are then discussed.