Background & Aims
The perception of itch is influenced by psychosocial factors, illustrated by its contagiousness when merely observing someone else scratching or talking about itch[6]. Patients with chronic itch, e.g., due to skin conditions, are more susceptible to itch contagion, which may contribute to their symptoms[6]. Empathy and self-consciousness were found to be associated with itch contagion[6]. Recently, the behavioral immune system (BIS), a psychological mechanism detecting and behaviorally acting upon cues indicating presence of potentially infectious pathogens[5], has also been suggested to play a role in contagious itch[7]. Triggering the BIS may induce itch and scratching to remove potential parasites from one’s own skin. This study investigated the extent to which visibility of a skin disease, talking about itch, and scratching can induce itch, and how individual characteristics, including dispositional empathy, self-consciousness, and pathogen disgust (reflecting BIS) are involved.
Methods
Circa 90% of 375 adults from the general population have been included. The study was carried out as an online questionnaire using Qualtrics. Contagious itch was investigated by showing the participants various video vignettes. At baseline, neutral topics were discussed with the skin condition being covered. In subsequent vignettes, the visual (visible psoriasis plaques versus visible psoriasis plaques with scratching) and verbal content (neutral topic versus talking about itch) were manipulated. Directly after each vignette, participants reported their own perceived levels of itch and urge to scratch. Various questionnaires were administered including the Self-Consciousness Scale[3], Interpersonal Reactivity Index measuring empathy[2], and the Pathogen Disgust Scale of the Three Domains of Disgust Scale[4]. Perceived itch and urge to scratch were compared between conditions, and correlation coefficients explored associations between the individual characteristics and induced itch.
Results
Preliminary analyses in the available data indicated that, when the topic was neutral, perceived itch was significantly higher when the skin condition was visible as compared to the baseline with invisible skin condition (p<0.001). Significantly more itch was induced when the patient in the vignette talked about itch as compared to both the baseline and the condition with merely a visible skin condition (both p<0.001). Scratching by the patient in the vignette did not have a significantly additive effect when talking about itch, but it did lead to significantly more itch when neutral topics were discussed (p<0.001). Comparable results were obtained for the outcome urge to scratch. Itch contagion (level of itch after manipulation minus baseline itch) was positively related (small correlation coefficients) to the individual factors empathy, self-consciousness, and pathogen disgust sensitivity.
Conclusions
These preliminary findings support that contagious itch can significantly be induced by observing someone with a skin condition, but more so by scratching or talking about itch. The combination of scratching and talking about itch does not have an additive effect. Results further confirm the role of dispositional empathy, self-consciousness in contagious itch. Now, to our knowledge, for the first time, also a direct link was found between the behavioral immune system and contagious itch. It is recommended that the role of this system is further investigated in itch perception, particularly how it may contribute to symptoms in patients with chronic itch.
References
[1] Cevikbas F, Lerner EA. Physiology and Pathophysiology of Itch. Physiological Reviews 2020;100:945–982.
[2] Davis MH. A Multidimensional Approach to Individual Differences in Empathy. JSAS Catalog of Selected Documents in Psychology.1980, Vol. 10. p. 85.
[3] Fenigstein A, Scheier MF, Buss AH. Public and private self-consciousness: Assessment and theory. Journal of Consulting and Clinical Psychology 1975;43:522–527.
[4] Olatunji BO, Adams T, Ciesielski B, David B, Sarawgi S, Broman-Fulks J. The Three Domains of Disgust Scale: Factor Structure, Psychometric Properties, and Conceptual Limitations. Assessment 2012;19:205–225.
[5] Schaller M. The behavioural immune system and the psychology of human sociality. Phil Trans R Soc Lond B Biol Sci 2011;366:3418–3426.
[6] Schut C, Grossman S, Gieler U, Kupfer J, Yosipovitch G. Contagious itch: what we know and what we would like to know. Front Hum Neurosci 2015;9:57.
[7] Sutter M, Kamber M, Navarini A, Mueller SM. Contagious Itch, Disgust and Empathy in a Family with Scabies and their Treating Medical Staff: An Exploratory Study. Acta Derm Venereol 2022;102:adv00816.
Presenting Author
Antoinette van Laarhoven
Poster Authors
Topics
- Specific Pain Conditions/Pain in Specific Populations: Itch