Generalized eruptive keratoacanthoma with vitiligo followed by the development of prurigo nodularis: A case report and published work review

Prurigo Nodularis: Pathogenesis and the Horizon of Potential Therapeutics

Chronic pruritus that lasts for over 6 weeks can present in various forms, like papules, nodules, and plaque types, with prurigo nodularis (PN) being the most prevalent. The pathogenesis of PN involves the dysregulation of immune cell-neural circuits and is associated with peripheral neuropathies, possibly due to chronic scratching. PN is a persistent and challenging condition, involving complex interactions among the skin, immune system, and nervous system. Lesional skin in PN exhibits the infiltration of diverse immune cells like T cells, eosinophils, macrophages, and mast cells, leading to the release of inflammatory cytokines and itch-inducing substances. Activated sensory nerve fibers aggravate pruritus by releasing neurotransmitters, perpetuating a vicious cycle of itching and scratching. Traditional treatments often fail, but recent advancements in understanding the inflammatory and itch transmission mechanisms of PN have paved the way for innovative therapeutic approaches, which are explored in this review.

Prurigo nodularis: Epidemiology and clinical features

Prurigo nodularis (PN) is a chronic inflammatory skin disease characterized by intensely pruritic, hyperkeratotic nodules that favor the extensor surfaces of the extremities and the trunk. In addition to its significant impact on quality of life, many patients with PN are recalcitrant to therapy because there are currently no therapies approved by the US Food and Drug Administration. In the first article of this 2-part continuing medical education series, we describe the broader epidemiology, patient demographics, physical examination findings, and symptoms to aid in the timely recognition and diagnosis of PN. Furthermore, we quantify the burden of comorbidities in PN by discussing the broad spectrum of systemic diseases and mental health conditions that have been associated with this condition. The second article of this 2-part series focuses on the pathogenesis of PN and provides detailed algorithms for comprehensive work-up and management.