Pathogenesis and Treatment of Pruritus

Abstract

Classification of itch into four categories-pruritoceptive, neurogenic, neuropathic, and psychogenic-has proven to be of utility to clinicians and investigators. Itch is recognized to be transmitted by dedicated afferent neurons, and a matrix of cerebral cortical loci involved in perception and the desire to scratch has been recognized. This highlights the multidimensional nature of the itch sensation. Some of the many mediators of itch, especially relevant in pruritogenic itch, are the result of cross-talk between dermal mast cells and adjacent cutaneous afferents. Keratinocytes of the epidermis express many neuropeptides, and their receptors are far from passive bystanders in the neurophysiology of itch. Mediators can also act centrally (eg, opioid peptides that act on micro receptors in the central nervous system). The pathophysiology of pruritus in neurogenic itch caused by common systemic diseases is gradually being elucidated, especially in the itch of cholestasis, although the molecular basis of itching in chronic renal failure remains elusive. Better understanding of the mediators of itch and their receptors has led to the imminent development of novel anti-itch compounds, including interleukin-31 inhibitors, histamine H4-receptor antagonists, and neurokinin-1 receptor antagonists.

Ondansetron to Treat Pruritus Due to Cholestatic Jaundice

“…5 The process of this sensation involves skin receptors, the peripheral nervous system, and specific regions of the brain and central nervous system. 6,7 Furthermore, as the perception of itch is highly subjective, it may vary from person to person. As itch has traditionally been a difficult symptom to classify and treat, various investigators have proposed systems of classification.…”

Pathogenese des Pruritus

“…B. in atopischer Haut auf Th2-Zellen aktiviert, schütten diese mehr Pruritus-vermittelndes Interleukin 31 (IL-31) aus [6]. H4-Antihistaminika sind derzeit in der Entwicklung und zeigten im Tiermodell überzeugende antipruritische Effekte, so dass diese zukünftig bei der atopischen Dermatitis (AD) einen wichtigen Stellenwert erhalten könnten [4,7].…”

An Investigator Blinded Randomized Study Evaluating HOCl in the Treatment of Atopic Dermatitis-Associated Pruritus

“…3 There are 2 mechanisms by which HOCl may reduce pruritus: 1) by its microbicidal qualities, particularly in the case of Staphylococcus aureus; and 2) by its antiinflammatory qualities, which help reduce the activity of histamine, leukotriene B4, and interleukin-2, all of which contribute to the pathophysiology of itch. [4][5][6][7] Here we present the results of a 3-day study designed to evaluate the effect of HOCl on pruritus in patients with AD.…”