Itch

Placebo and nocebo effects on itch: a review of experimental methods Itch is a commonly experienced symptom of acute and chronic dermatological and systemic conditions. Placebo and nocebo effects, positive and negative effects experienced after both real and sham interventions, putatively due to positive or negative outcome expectancies, can have a significant impact on the experience of itch and its treatment. Experimental methods to induce and study placebo and nocebo effects on itch have been developed, utilizing various combinations of expectancy-induction methods (eg, conditioning, verbal suggestions) and short-acting itch-evoking stimuli (eg, histamine, electrical, or mechanical stimulation). The aim of this review is to describe the current research methods used to induce placebo and nocebo effects on itch, and the results of these studies. The benefits and drawbacks of different expectancy-induction methods and itch-evoking stimuli are described, and future directions for research and clinical application are discussed. Sponsorships or competing interests that may be relevant to content are disclosed at the end of this article. Published online 2 July 2019 Corresponding author. Address: Wassenaarseweg 52, Leiden 2333RB, The Netherlands. Tel.: +31 71 527 3008; fax:+31 71 527 3619 E-mail address: j.s.blythe@fsw.leidenuniv.nl (J.S. Blythe). Received August 23, 2018 Accepted May 18, 2019 This is an open access article distributed under the Creative Commons Attribution License 4.0 (CCBY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. http://creativecommons.org/licenses/by/4.0/ Copyright © 2019 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of the International Forum for the Study of Itch. All rights reserved.

A systematic review of questionnaires on itch by the Special Interest Group "Questionnaires" of the International Forum for the Study of Itch (IFSI) Introduction: Itch can be perceived differently across patients and it can affect daily life in various ways. It is essential to assess those aspects that are relevant for the individual patient's needs to improve treatment of patients suffering from acute or chronic itch. The International Forum for the Study on Itch (IFSI) Special Interest Group on "Questionnaires" aims to propose tools to assess different dimensions of itch and improve patient care. As a first step, this study aimed at a systematically reviewing existing patients' self-report questionnaires on itch. Materials and methods: The databases PubMed, PsycINFO, and CINAHL were systematically searched for any scientific publication describing patients' self-report questionnaires that assess itch-related information (≥2 items). Information about the publication was extracted by 2 experts as well as which of the 14 predefined dimensions of itch (by the IFSI Special Interest Group) were assessed within the questionnaire, for instance, duration of itch, itch aggravating or relieving factors, and effects on quality of life. Results: From a total of 5282 records, 58 articles were derived describing 62 questionnaires. Over half of the questionnaires were developed for dermatological conditions, and the vast majority targeted at adults. Most questionnaires address itch-related disability and itch intensity. Affective qualities of itch, coping with itch, response to current itch treatment, and the opinion on the origin of itch are infrequently asked for. Discussion: The number and content of the items within a dimension vary greatly. Measurement properties of the questionnaires were not systematically addressed, as these were often not reported in the original publication. Future research should focus on selecting adequate and reliable (sub)scales to develop a modular questionnaire system in order to uniformly assess the individual patient's demands and improve care. Sponsorships or competing interests that may be relevant to content are disclosed at the end of this article. Published online 26 June 2019 Corresponding author. Address: Department of Dermatology—Occupational Dermatology, Ruprecht Karls University Heidelberg, Voßstr. 2, Heidelberg DE-69115, Germany. Tel: +49-6221-56-8752; fax: +49-6221-56-5584. E-mail: elke.weisshaar@med.uni-heidelberg.de (E. Weisshaar). Received March 22, 2019 Accepted May 15, 2019 This is an open access article distributed under the Creative Commons Attribution License 4.0 (CCBY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. http://creativecommons.org/licenses/by/4.0/ Copyright © 2019 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of the International Forum for the Study of Itch. All rights reserved.

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