Itch, a complex symptom: topical approach
A review on topical products and cosmetic actives for the treatment of itch. Part 1.
Pruritus, or itch, is an unpleasant sensation provoking the desire to scratch, it is a major symptom in numerous dermatological and systemic diseases and can have a dramatic impact on the quality of life. The ultimate determination of the cause of pruritus remains a challenge for any physician: every effort must be made to identify primary and secondary causes of the disorder, and this requires a meticulous history-including medicaments’ intake that can elicit pruritus- and physical examination. The pathogenesis of itch is diverse and involves a complex network of cutaneous and neuronal cells, thus anti-pruritic therapy is often directed against a variety of targets, including the epidermal barrier, immune system, or the nervous system. Topical therapy is the mainstay of dermatologic management of acute or localized itch or in patients with contraindications to systemic therapies. This review will summarize current topical therapies to treat pruritus.
The skin constitutes a barrier between ‘outside’ environment and ‘inner’ body, therefore, one of its main tasks is to protect the organism against harmful influences from the outside. To fulfil this task, the skin is armed with an effective communication and control system: in all layers of the skin, specialized sensory and efferent nerve branches appear to form an overall dense neural network. One main ‘outside-to-inside’ interaction causes sensations of itch. Itch, also known as pruritus, is defined as “an unpleasant sensation evoking the desire to scratch” (1). As an acute sensation, pruritus fulfils an essential part of the innate defence mechanism of the body and it is a major characteristic and one of the most debilitating symptoms in allergic and atopic diseases and the diagnostic hallmark of atopic dermatitis (AD). Next to pain, itch serves as an alarm system to remove possibly damaging or harming substances from the skin. If itch persists for 6 weeks or longer, it is defined as chronic pruritus by the International Forum for the Study of Itch (IFSI) (2). Chronic pruritus is a major diagnostic and therapeutic problem ...