Topical Hypochlorous Acid (HOCl) as a Potential Treatment of Pruritus

Abstract

Topical hypochlorous acid (HOCl) has recently been proposed as a treatment of pruritus. However, it is not known whether topical HOCl decreases or promotes pruritus. This review sheds light on this poorly understood subject. This article describes the pathophysiology of pruritus, current treatments of pruritus, and how pH determines the properties of HOCl in solution. The article then proposes two mechanisms by which HOCl may reduce pruritus: 1) HOCl is microbicidal to cutaneous pathogens, especially Staphylococcus aureus in atopic dermatitis; 2) HOCl is anti-inflammatory and reduces the activities of histamine, leukotriene B4, and interleukin-2, all of which are implicated in the pathophysiology of itch. Lastly, this article describes conditions under which HOCl may actually cause pruritus as an adverse effect. For example, HOCl increases the activity of nerve growth factor, which promotes itch. Prolonged or high-dose HOCl exposure may also cause irritant contact dermatitis, or less commonly, allergic contact dermatitis. © 2013 Springer Science+Business Media New York.