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Summary: Background: Previous research has mainly used skin‐manipulating methods to induce itch. In comparison, itch induced by audiovisual stimuli lacks direct skin manipulation. Objectives: The aim of this double blind, noninferiority study was to test the experimental hypothesis that itch induced by audiovisual stimuli is noninferior to itch induced by histamine iontophoresis in case of priming and without priming. Methods: In 80 of 160 healthy volunteers itch was induced by histamine iontophoresis, while in the other 80 itch was induced by audiovisual stimulation. Forty people in each group experienced either an initial resting phase or dermal priming. Itch intensity was measured by visual analogue scales, while scratch duration and frequency were video‐recorded and evaluated by two independent raters. In addition, itch quality and location were measured by self‐report. Results: Itch induced by audiovisual stimuli was inferior to itch induced by histamine iontophoresis in the absence of dermal priming. However, in the case of priming, maximal itch induced by audiovisual stimuli was not inferior to maximal itch induced by histamine iontophoresis. Additionally, differences in itch quality and location were observed. Conclusions: The finding that maximal audiovisually‐induced itch was comparable with maximal histamine itch only after priming emphasizes that attention plays a dominant role in mentally‐induced itch. The comparability of maximal histamine and audiovisually‐induced itch in the case of priming opens up new research opportunities. What's already known about this topic? Itch is a multidimensional sensation that is altered by, among other things, attention.To induce itch in basic research, different methods are used, which are partially invasive or cause skin manipulation.Noninvasive audiovisual stimuli can be used to induce itch. What does this study add? This study investigated whether itch induced by audiovisual stimuli is noninferior to itch induced by histamine iontophoresis.Itch induced by audiovisual stimuli is noninferior with regard to maximal intensity in the case of priming.Noninferiority was not shown in the case of no priming, emphasizing the role of attention in itch induction.Histamine and audiovisually‐induced itch differ in terms of quality and location, but not in affective reaction. Linked Comment: van Laarhoven and Holle. Br J Dermatol 2020; 182:1088–1089. Plain language summary available online [ABSTRACT FROM AUTHOR]

Background: Body dysmorphic disorder (BDD) is a common psychiatric disorder associated with high costs for healthcare systems as patients may repeatedly ask for different, often not effective, interventions. BDD symptoms are more prevalent in patients with dermatological conditions than in the general population, but there are no large sample studies comparing the prevalence of BDD symptoms between patients with dermatological conditions and healthy skin controls., Objectives: To compare the prevalence of BDD symptoms between patients with different dermatological conditions and healthy skin controls and to describe sociodemographic, physical and psychological factors associated with BDD symptoms to identify patients who may have a particularly high chance of having this condition., Methods: This observational, cross-sectional, comparative multicentre study included 8295 participants: 5487 consecutive patients with different skin diseases (56% female) recruited among dermatological outpatients at 22 clinics in 17 European countries, and 2808 healthy skin controls (66% female). BDD symptoms were assessed by the Dysmorphic Concern Questionnaire. Sociodemographic data and information on psychological factors and physical conditions were collected. Each patient was given a dermatological diagnosis according to ICD-10 by a dermatologist. The study was registered with number DRKS00012745., Results: The average participation rate of invited dermatological patients was 82.4% across all centres. BDD symptoms were five times more prevalent in patients with dermatological conditions than in healthy skin controls (10.5% vs. 2.1%). Patients with hyperhidrosis, alopecia and vitiligo had a more than 11-fold increased chance (adjusted Odds Ratio (OR) > 11) of having BDD symptoms compared with healthy skin controls, and patients with atopic dermatitis, psoriasis, acne, hidradenitis suppurativa, prurigo and bullous diseases had a more than sixfold increased chance (adjusted OR > 6) of having BDD symptoms. Using a logistic regression model, BDD symptoms were significantly related to lower age, female sex, higher psychological stress and feelings of stigmatization., Conclusions: Clinical BDD symptoms are significantly associated with common dermatological diseases. As such symptoms are associated with higher levels of psychological distress and multiple unhelpful consultations, general practitioners and dermatologists should consider BDD and refer patients when identified to an appropriate service for BDD screening and management., (© 2022 The Authors. British Journal of Dermatology published by John Wiley & Sons Ltd on behalf of British Association of Dermatologists.)