DOI: 10.1111/jdv.17077 JEADV ORIGINAL ARTICLE Google search trends for itch in Europe: a retrospective longitudinal study M.P. Pereira,1,† S. Ziehfreund,2,† M. Rueth,2 T. Ewering,1 F.J. Legat,3 J. Lambert,4 5 6 6 7 8 J. Elberling, L. Misery, E. Brenaut, E. Papadavid, S. Garcovich, A.W.M. Evers,9 J.A. Halvorsen, 10 J.C. Szepietowski, 11 A. Reich, 12 M. Gonc alo, 13 A. Lvov,14 S. Bobko,14 €nder,1 E. Serra-Baldrich,15 J. Wallengren,16,17 E. Savk,18 T. Leslie,19 S. Sta 2 A. Zink, * , on behalf of the EADV Task Force Pruritus 1 Department of Dermatology and Center for Chronic Pruritus, University Hospital Mu €nster, Mu €nster, Germany 2 Department of Dermatology and Allergy, Technical University of Munich, Munich, Germany 3 Department of Dermatology, Medical University of Graz, Graz, Austria 4 Department of Dermatology, University Hospital of Antwerp, University of Antwerp, Antwerp, Belgium 5 Department of Dermatology, University Hospital Gentofte, Copenhagen, Denmark 6 Department of Dermatology, University Hospital of Brest, Brest, France 7 Department of Dermatology and Venereology, University of Athens Medical School, Attikon Hospital, Athens, Greece 8 Dipartimento di Scienze Mediche e Chirurgiche, Fondazione Policlinico Universitario A. Gemelli IRCCS, UOC Dermatologia, Universit a Cattolica del Sacro Cuore, Rome, Italy 9 Department of Health, Medical and Neuropsychology, Institute of Psychology, Leiden University, Leiden, The Netherlands 10 Department of Dermatology, Oslo University Hospital, University of Oslo, Oslo, Norway 11 Department of Dermatology, Venereology and Allergology, Wroclaw Medical University, Poland 12 Department of Dermatology, University of Rzeszow, Rzeszo w, Poland 13 Department of Dermatology, University Hospital and Faculty of Medicine, University of Coimbra, Coimbra, Portugal 14 Moscow Scientific and Practical Center of Dermatovenereology and Cosmetology, Moscow, Russia 15 Department Dermatology, Sant Pau Hospital, Barcelona, Spain 16 Department of Clinical Sciences Lund, Dermatology and Venereology, Lund University, Lund, Sweden 17 Skane University Hospital, Lund, Sweden 18 Department of Dermatology, Aydin Adnan Menderes University, Aydın, Turkey 19 Royal Free Hospital, London, UK *Correspondence: A. Zink. E-mail: alexander.zink@tum.de Abstract Background Itch is a common symptom in the general population. Affected individuals often do not seek medical con- sultation and rely on Internet searches to obtain information regarding their itch. Objectives The aim of this study was to attain insights into common concerns of the general population regarding itch can by analysing itch-related Internet search behaviour. Methods Google AdWords Keyword Planner was used to assess search volumes for itch-related terms in 15 European countries between September 2014 and August 2018. All identified keywords were qualitatively categorized. Itch-related terms were descriptively analysed and are shown as number of searches/100 000 inhabitants. Results The search volume for the keyword ‘itch’ per 100 000 inhabitants was highest in Northern Europe, followed by Eastern, Central and Southern Europe. In 4/15 countries, itch was searched for more often in the autumn/winter months com- pared to in the spring/summer months. Most itch-related terms were related to dermatological conditions such as inflamma- tory skin diseases (e.g. psoriasis, atopic dermatitis), allergic or immunologic conditions (e.g. urticaria), and infectious diseases or infestations (e.g. scabies). In terms of body location, genitoanal itch dominated the searches. Symptoms and signs related to itch, possible non-dermatological aetiologies, and treatment options were also among the most searched terms. Conclusions These analyses provided for the first time insights into the search behaviour patterns related to itch across Europe. People from Northern and Eastern Europe are more likely to seek online information regarding itch. Causes for the itch, especially dermatological conditions, and genitoanal itch are the most important concerns for Inter- net users. This unconventional and inexpensive method identifies medical needs of people beyond the medical setting, including people who do not seek medical consultation. Accordingly, the data could be used to guide public health inter- ventions and manage respective inhabitants’ medical needs. Received: 24 July 2020; revised: 10 October 2020; Accepted: 21 October 2020 JEADV 2021, 35, 1362–1370 © 2020 The Authors. Journal of the European Academy of Dermatology and Venereology published by John Wiley & Sons Ltd on behalf of European Academy of Dermatology and Venereology This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes. 14683083, 2021, 6, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/jdv.17077 by Readcube (Labtiva Inc.), Wiley Online Library on [23/05/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License Internet search trends for itch in Europe 1363 Conflicts of interest MP Pereira is an investigator for Trevi Therapeutics; is a consultant for Galderma; and has received speaker honoraria/ travel fees from Galderma, Menlo Therapeutics, Novartis, and Trevi Therapeutics. S Ziehfreund has received speaker honoraria and travel fees from Novartis. FJ Legat is an investigator for DS Biopharma, Eli Lilly, Galderma, Pfizer, Menlo Therapeutics, Trevi Therapeutics. He is a consultant for Galderma, a member of the advisory boards, and/or has received speaker honoraria/travel fees from AbbVie, Almirall, Celgene, Eli Lilly, Janssen, Leo Pharma, Menlo Therapeutics, Novar- tis, Pfizer, Trevi Therapeutics and Vifor Fresenius Medical Care Renal Pharma. J Lambert is investigator for Pfizer, Leo Pharma, Sanofi, Galderma, and he received consultancy/speaker honoraria from AbbVie, Leo Pharma, Galderma, Eli- Lilly, Janssen-Cilag, Roche-Posay, Pierre-Fabre, Novartis, UCB Pharma, Meda Pharma, Mylan, Celgene and Bioderma. L Misery is a consultant for Galderma, Menlo, Trevi and Sanofi and was investigator for Galderma, Trevi and Sanofi. E Brenaut is an investigator for Biogen and Galderma, and is a consultant and/or member of the advisory board for Jans- sen, Lilly, Celgene, Novartis and Pfizer, and received financial support from Sanofi, AbbVie. S Garcovich has received consulting support from companies including Menlo Therapeutics. JC Szepietowski is an investigator for AbbVie, Amgen, Boehringer Ingelheim, Galapagos, InflaRX, Pfizer, UCB, Incyte, Janssen, Helm, Merck, Menlo Therapeutics, Novartis, Regeneron, Trevi, advisor for AbbVie, Leo Pharma, Novartis, Pierre-Fabre, Menlo Therapeutics, Sanofi Gen- zyme, Sienna Biopharmaceuticals, Trevi, and speaker for AbbVie, Berlin-Chemie Menarini, Eli Lilly, Janssen, Leo Pharma, Novartis, Sanofi-Genzyme and SunFarm. A Reich is a consultant or speaker for AbbVie, Bioderma, Celgene, Chema Elektromet, Eli Lilly, Galderma, Janssen, Leo Pharma, Medac, Menlo Therapeutics, Novartis, Pierre-Fabre, Sandoz and Trevi; Principal Investigator or Subinvestigator in clinical trials sponsored by AbbVie, Drug Delivery Solutions Ltd, Gal- derma, Genentech, Janssen, Kymab Limited, Leo Pharma, Menlo Therapeutics, MetrioPharm, MSD, Novartis, Pfizer and Trevi. M Gonc alo has been a consultant and received speaker honoraria for Novartis, and Sanofi. A Lvov is a consultant for Galderma, and Novartis and has received speaker honoraria/travel fees from Galderma, Bayer, LEO and Pierre Fabre. S Bobko has received speaker honoraria/travel fees from LEO. E Serra-Baldrich is an investigator, a consultant or gave presentations for Regeneron, Sanofi, Stiefel/GSK, Pierre Fabre, La Roche Posay, Leo Pharma, Novartis, Almirall, Pfizer, €nder is an investigator for Der- Galderma, Lilly and AbbVie. TA Leslie has been a consultant for Menlo and Novartis. S Sta masence, Kiniksa, Galderma, Menlo Therapeutics, Novartis and Trevi Therapeutics, and is a consultant and/or member of the advisory board for Almirall, Beiersdorf, Bellus Health, Cara Therapeutics, Celgene, Clexio Biosciences, Galderma Laboratorium, Galderma S.A., LEO, Menlo Therapeutics, Novartis, Sienna Biopharmaceuticals, Trevi Therapeutics and Vanda Pharmaceuticals. A Zink has been an advisor and/or received speaker’s honoraria and/or received grants and/or participated in clinical trials of the following companies: AbbVie, Amgen, lmirall, Beiersdorf Dermo Medical, Bencard Allergie, BMS, Celgene, Eli Lilly, GSK, Janssen Cilag, Miltenyi Biotec, Pfizer, Novartis, Sanofi-Aventis, Takeda Pharma. T Ewering, J Elberling, E. Papadavid, AWM Evers, JA Halvorsen, J Wallengren, E Savk and M Rueth declare no conflicts of interest. Funding source This study was supported by the European Academy of Dermatology and Venereology (EADV, No. 2016-012 to MP). Introduction fraction of people affected by itch do not seek medical consulta- Itch is the most frequent symptom in dermatology, occurring in tion, especially individuals with only occasionally itching or more than 50% of patients.1 Furthermore, the general popula- those with less severe pruritus. For these people and their rela- tion frequently suffers from itch, predominantly from chronic tives, who often suffer with them, no reliable data exist regarding itch (i.e. lasting >6 weeks), with a prevalence ranging from their condition and their medical needs. 13.5% to 31.2%.2–4 The impact of itch on quality of life is sub- Since the Internet is often consulted for health information, stantial and there is a higher prevalence of depression and suici- analysing Internet search behaviour in relation to itch can pro- dal ideation among people with severe itch.5,6 Patients with vide outside of the medical setting insights into the concerns of acute severe itch (e.g. in urticaria or scabies) or those with people experiencing itch.7 Previous studies analysing itch-related chronic pruritus (e.g. atopic eczema or psoriasis) are frequently Internet searches in Germany revealed that more searches examined by physicians. However, we speculate that a large occurred during the colder months of the year, suggesting an influence of climate conditions on the incidence of itch.8 Most † searches were associated with skin conditions such as eczema Shared first-authorship. JEADV 2021, 35, 1362–1370 © 2020 The Authors. Journal of the European Academy of Dermatology and Venereology published by John Wiley & Sons Ltd on behalf of European Academy of Dermatology and Venereology 14683083, 2021, 6, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/jdv.17077 by Readcube (Labtiva Inc.), Wiley Online Library on [23/05/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License 1364 Pereira et al. Table 1 Searched keywords in original language and the United Kingdom) between September 2014 and August Country Searched keyword in original language 2018. For each country, the translated layman term of the key- Austria Juckreiz word itch in the corresponding local languages was used for Belgium mangeaison, jeuk, prurit de analysis. Two terms translating itch were chosen in France, Denmark kløe Greece and Russia, and three terms in Belgium and Spain. In the France mangeaison, prurit de remaining countries, only one term was used for the analysis Greece Fagoura, knismos (Table 1). For the analyses, the identified keywords for countries Italy prurito with two and three terms for itch were summarized, and dupli- The Netherlands jeuk cates were removed. We set the region and language settings to Norway kløe limit the search volume data using Google solely to users in the Poland swiaz d abovementioned countries, which included limiting the language Portugal ~o comicha settings to the main spoken languages of each respective country. Russia Зyд, Чecoткa The translation of the layman term and the back translation of Spain escozor, picazon, picor the 20 keywords most often searched was performed by investi- Sweden kl ada gators specialized in the field of itch in their own respective Turkey kasıntı countries (dermatologist FJL, JL, JE, LM, EB, EP, SG, JAH, JCS, United Kingdom itch AR, MG, AL, SB, ES-B, JW, ES, TL; health psychology: AWME); Two terms meaning itch were chosen in France, Greece, and Russia, and data collection and statistical analysis by the German research three terms in Belgium and Spain. In the remaining countries, only one term was used for the analysis. team consisting of specialists in the field of itch and Internet search analysis (MPP, SZ, MR, TE, SS, AZ). Even if up to 1036 keywords could be identified for a single country (range 637– and psoriasis. High search volumes for itch related to particular 1036), the 20–50 most frequently searched show an above aver- body parts, especially the genitoanal region and legs, were also age search volume. Thus, for a good data management the 20 recorded.9 keywords most often searched for in combination with itch were We analysed search volumes for itch and associated terms in determined for each country and analysed descriptively. Institu- 15 different European countries, as studies analysing itch-related tional review board approval and informed consent were not search volume (i.e. number of queries for a term on an Internet applicable for this study. search engine over a defined period of time) are missing for many other European countries. We used the Google search Statistics engine for our investigation since it is used by the vast majority IBM SPSS Statistics v. 26 (IBM Corporation, Armonk, NY, USA) of the European population.10 The aim of this study was to gain was used for statistical analyses. Search volume data were analysed insight into search behaviour patterns in relation to itch across descriptively and are shown as the number of searches per Europe to detect possible variations across European regions 100 000 inhabitants to allow comparisons between countries. We and to determine common concerns of the general population used Eurostat and the International Monetary Fund as sources for regarding itch. Although this study is mostly of explorative nat- the number of inhabitants per country (Table S1). For each coun- ure, based on previous studies performed in Germany,8,9 we try, the number of dermatologists per capita was calculated by hypothesize that (i) search volumes for itch are higher in the dividing the total number of dermatologists reported by Eurostat colder months than in the summer, (ii) there is a correlation for 2015 by the number of inhabitants. The number of dermatolo- between country search volume and supply of dermatologists, gists per capita could not be calculated for Russia. Cross-country and (iii) mostly skin conditions and genitoanal disorders are and regional comparisons of the overall itch-related search vol- searched for in connection with itch. ume were performed with one-way analyses of variance (ANOVA). Tukey’s range test was used for multiple comparisons Methods as post hoc tests. An unpaired t-test was used for comparisons of Google AdWords Keyword Planner was used to determine the search volume across regions and between spring/summer (April– Google search volume for itch. This tool was developed for opti- September) and autumn/winter months (October–March). We mizing advertisement but has been used previously for research used the non-parametric Spearman’s rho to correlate search vol- purposes. Google AdWords Keyword Planner delivers an esti- ume with the number of inhabitants and dermatologists per mate of the monthly search volume for selected keywords.8,9,11,12 capita. The 20 associated terms most searched for in combination In this retrospective longitudinal study, we analysed the search with itch were analysed qualitatively for each country and classi- volume for the keyword itch in 15 different European countries fied according to whether they referred to skin conditions, non- (Austria, Belgium, Denmark, France, Greece, Italy, the Nether- dermatological causes of itch, localization, symptoms or treat- lands, Norway, Poland, Portugal, Russia, Spain, Sweden, Turkey ment. A term could be attributed to multiple categories if JEADV 2021, 35, 1362–1370 © 2020 The Authors. Journal of the European Academy of Dermatology and Venereology published by John Wiley & Sons Ltd on behalf of European Academy of Dermatology and Venereology 14683083, 2021, 6, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/jdv.17077 by Readcube (Labtiva Inc.), Wiley Online Library on [23/05/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License Internet search trends for itch in Europe 1365 (a) 2500 2000 Denmark Norway 1500 Sweden Mean 1000 500 0 4 15 15 15 15 16 16 16 16 17 17 17 17 18 18 18 1 ct n r l ct n r l ct n r l ct n r l Ju Ju Ju Ju Ap Ap Ap Ap Ja Ja Ja Ja O O O O (b) 2500 2000 Austria Belgium France 1500 The Netherlands UK Mean 1000 500 0 14 15 5 5 15 16 6 6 16 17 7 7 17 18 8 8 r1 l1 r1 l1 r1 l1 r1 l1 ct n ct n ct n ct n Ju Ju Ju Ju Ap Ap Ap Ap Ja Ja Ja Ja O O O O (c) 2500 2000 Greece Italy Portugal 1500 Spain Turkey Mean 1000 500 0 14 15 5 5 15 16 6 6 16 17 7 7 17 18 8 8 r1 l1 r1 l1 r1 l1 r1 l1 ct n ct n ct n ct n Ju Ju Ju Ju Ap Ap Ap Ap Ja Ja Ja Ja O O O O (d) 2500 2000 Poland 1500 Russia Mean 1000 500 0 14 15 5 5 15 16 6 6 16 17 7 7 17 18 8 8 r1 l1 r1 l1 r1 l1 r1 l1 ct n ct n ct n ct n Ju Ju Ju Ju Ap Ap Ap Ap Ja Ja Ja Ja O O O O Figure 1 Search volume of itch-related keywords over time. Search volume for itch-related keywords over time in Northern (Panel a), Central (Panel b), Southern (Panel c) and Eastern (Panel d) European countries. Spring/summer months (April–September) are highlighted in red. Average number of searches for all 15 countries is shown by the red line. For each country, the translated layman term of the key- word itch in the corresponding local languages was used for analysis. Two terms meaning itch were chosen in France, Greece and Russia, and three terms in Belgium and Spain. In the remaining countries, only one term was used for analysis. JEADV 2021, 35, 1362–1370 © 2020 The Authors. Journal of the European Academy of Dermatology and Venereology published by John Wiley & Sons Ltd on behalf of European Academy of Dermatology and Venereology 14683083, 2021, 6, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/jdv.17077 by Readcube (Labtiva Inc.), Wiley Online Library on [23/05/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License 1366 Pereira et al. Table 2 Search terms associated with itch – skin conditions Table 3 Search terms associated with itch – non-dermatological causes Term Number of Country searches Term Number of searches Country per 100 000 per 100 000 Psoriasis 3409.38 AT, BL, FR, IT, NL, PL, PT, RU, Haemorrhoids 534.36 PL TR, UK Allergy 493.94 BL, DK, ES, NL, NO, Eczema 1795.21 AT, BL, DK, ES, FR, GR, NL, NO, PL, PT, RU, TR PL, RU, SE, TR, UK Varicocele 183.73 RU Urticaria 981.61 BL, FR, IT, PL, RU Pregnancy 55.59 UK Dermatitis 748.70 BL, ES, GR, IT, NL, PT, RU, UK Food intake 18.31 PT Atopic dermatitis/ 594.77 AT, BL, DK, NL, NO, PL, PT, SE Roundworms (anal itch) 17.65 ES eczema Urinating 16.94 ES Scabies 663.49 PL, RU, SE Number of searches per 100 000 inhabitants is shown as well as the coun- Mycosis/candidiasis 538.11 NO, PL, SE, TR tries in which the search term was among the top 20 most searched terms Papilloma 352.86 RU associated with itch. AT, Austria; BL, Belgium; DK, Denmark; ES, Spain; FR, Skin rash/redness 343.13 AT, BL, DK, GR, NL, NO, PL, SE, UK France; GR, Greece; IT, Italy; NL, The Netherlands; NO, Norway; PL, Acne 316.25 BL, IT, NL, RU Poland; PT, Portugal; RU, Russia; SE, Sweden; TR, Turkey; UK, United Furuncle 209.27 RU Kingdom. Seborrhoeic eczema 185.03 BL, NL, NO, PL, SE Couperose/Rosacea 178.08 BL, FR, RU ANOVA showed significant differences in the search volume Warts 118.61 RU between countries (P < 0.001). We recorded more queries Demodicosis 101.37 RU per 100 000 inhabitants in Northern European countries Dry skin/Xeroderma 60.47 BL, GR, NL, NO Lice 55.34 PT (Denmark, Norway, Sweden: 1087  620) compared to in Prurigo 44.07 BL, FR Eastern (Poland, Russia: 720  278; P < 0.001), in Central Nummular Eczema 37.74 DK, UK (Austria, Belgium, France, the Netherlands, United Kingdom: Mole 36.94 UK 612  214; P < 0.001) and in Southern European countries Quincke oedema 18.45 PL (Greece, Italy, Portugal, Spain, Turkey: 599  400; Hand Eczema 17.93 DK, NL P < 0.001). Eastern European countries also had more Dyshidrotic eczema 14.64 BL, NL queries than Southern European countries (P = 0.05). Insect Bite 4.56 GR The search volume per 100 000 inhabitants was higher in the Contact Eczema 2.12 DK autumn/winter months compared to in the spring/summer Number of searches per 100 000 inhabitants is shown as well as the coun- months in Austria (532  80 vs. 472  63; P = 0.006), the tries in which the search term was among the top 20 most searched terms Netherlands (1013  133 vs. 933  112; p = 0.028), Poland associated with itch. AT, Austria; BL, Belgium; DK, Denmark; ES, Spain; FR, (1058  140 vs. 881  107; P < 0.001) and the United King- France; GR, Greece; IT, Italy; NL, The Netherlands; NO, Norway; PL, Poland; PT, Portugal; RU, Russia; SE, Sweden; TR, Turkey; UK, United dom (639  88 vs. 592  72; P = 0.048). In contrast, in Italy Kingdom. (403  49 vs. 442  43; P = 0.005) and in Portugal (1268  183 vs. 1408  192; P = 0.013) more searches were appropriate. Terms not related to itch were excluded from the performed in the spring/summer months. In the remaining analyses as per the investigators’ assessment. countries, we recorded no differences in search volume between Data are shown as mean  standard deviation. The level of the autumn/winter and spring/summer months (P > 0.05). significance was set at a = 0.05 for all analyses. Classification of itch-related keywords Results Table S2 shows the 20 most often searched terms associated with itch translated to English for each country, while the terms in Search volume of the itch-related keywords over time the local languages can be consulted in Table S3. Excluded key- In total we recorded 145 755 050 searches for itch-related words not related to itch are given in Table S4. keywords between September 2014 and August 2018. The average number of searches per 100 000 inhabitants per Skin conditions Most search terms associated with itch were month was 717. Sweden (1894  179), Portugal related to skin diseases. Among these, chronic inflammatory (1338  198) and the Netherlands (973  128) had the conditions were the most searched for including psoriasis highest average number of queries per month per 100 000 (3409.38/100 000), eczema (1795.21/100 000) and atopic der- inhabitants, while Spain (321  45), Turkey (325  66) and matitis/eczema (594.77/100 000). The term ‘eczema’ and ‘atopic France (389  46) had the lowest (Fig. 1). One-way eczema’ is considered separately for this analysis, since the broad JEADV 2021, 35, 1362–1370 © 2020 The Authors. Journal of the European Academy of Dermatology and Venereology published by John Wiley & Sons Ltd on behalf of European Academy of Dermatology and Venereology 14683083, 2021, 6, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/jdv.17077 by Readcube (Labtiva Inc.), Wiley Online Library on [23/05/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License Internet search trends for itch in Europe 1367 term ‘eczema’ may refer to an origin other than atopic, such as, for itch are provided in the section above. Searched terms associ- e.g., allergic or seborrhoeic. Urticaria and Quincke oedema were ated with non-dermatological causes are provided in Table 3 also among the most searched terms with 981.61 and 18.45 and include genitoanal diseases (haemorrhoids, 534.36/100 000; queries per 100 000 inhabitants, respectively, as well as infec- varicocele, 183.73/100 000; anal roundworms, 17.65/100 000), tious diseases (scabies, 663.49/100 000; fungal infections, allergic conditions (allergy, 493.94/100 000; food intake, 18.31/ 538.11/100 000; papilloma/warts, 471.47/100 000; lice, 55.34/ 100 000) and physiological processes (pregnancy, 55.59/ 100 000). A complete list of the search terms related to skin dis- 100 000; urinating 16.94/100 000). eases is provided in Table 2. Body location Figure 2 provides an overview of the body loca- Non-dermatological causes for itch The cause for the itch is a tions searched for in association with itch. Genitoanal itch dom- common concern in people affected by itch. There were 58.01/ inated the searches with 47.9% (720.5/100 000) of the searches 100 000 queries for causes and 34.65/100 000 for Why does itch related to body location. Genital itch was searched more often happen?. The searched keywords related to dermatological causes (430.85/100 000) than perianal itch (289.65/100 000). In only (a) HEAD • Scalp: 103.31 (GR, IT, NO, PT, SE) • Eyes: 92.07 (ES, UK) UPPER EXTREMITY • Throat: 25.92 (NO, UK) • Face: 16.37 (NL, NO) • Hands: 86.01 (DK, FR, IT, NL, UK) • Ears: 11.21 (AT, DK, NO) • Arms: 5.18 (IT) TRUNK ALL OVER • Back: 38.87 (FR, UK) • Spine: 23.49 (PT) • 89.78 (AT, DK, FR, IT, UK) LOWER EXTREMITY • Legs: 149.13 (AT, BL, DK, ES, FR, IT, TR, UK) • Feet: 136.60 (FR, GR, IT, TR, UK) • Ankles: 5.97 (IT) GENITOANAL • Genital: 430.85 (DK, FR, GR, NO, PT, RU, SE, TR) • Perianal: 289.65 (AT, DK, ES, GR, PL, SE, TR) (b) All over 6.0% Head 16.5% 4.1% Trunk 47.9% Genitoanal 6.1% 19.4% Upper extremity Lower extremity Figure 2 Search terms associated with itch – body location. (a) Cumulative number of searches per 100 000 inhabitants is shown for each body location as well as the countries in which the search term was among the top 20 most searched terms associated with itch. (b) Percentage of number of searches per body location. AT, Austria; BL, Belgium; DK, Denmark; ES, Spain; FR, France; GR, Greece; IT, Italy; NL, The Netherlands; NO, Norway; PL, Poland; PT, Portugal; RU, Russia; SE, Sweden; TR, Turkey; UK, United Kingdom. JEADV 2021, 35, 1362–1370 © 2020 The Authors. Journal of the European Academy of Dermatology and Venereology published by John Wiley & Sons Ltd on behalf of European Academy of Dermatology and Venereology 14683083, 2021, 6, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/jdv.17077 by Readcube (Labtiva Inc.), Wiley Online Library on [23/05/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License 1368 Pereira et al. Table 4 Search terms associated with itch – symptoms terms neonatal (18.33/100 000) and baby (14.36/100 000) were Term Number of searches per 100 000 Country also recorded. Discharge 123.54 ES, NO, SE Erythema 66.80 IT Discussion Tooth pain 49.51 PL This large multicentre retrospective longitudinal study provides Dandruff 34.97 ES for the first time valuable data regarding Internet search beha- Burning 22.00 NO, SE viour patterns related to itch across Europe. We gained consid- Eye pain 11.75 ES erable insight into healthcare relevant concerns and the needs of Bumps 10.28 NL people who suffer from itch beyond the medical setting. Stinging 4.89 DK We recorded an average of 717 searches per 100 000 inhabi- Bleeding (anal) 4.18 GR tants per month. Most Northern (exception: Denmark) Euro- Number of searches per 100 000 inhabitants is shown as well as the coun- pean countries showed more searches than average, and Central tries in which the search term was among the top 20 most searched terms European (exception: the Netherlands) and Southern European associated with itch. AT, Austria; BL, Belgium; DK, Denmark; ES, Spain; FR, countries (exception: Portugal) showed less searches than aver- France; GR, Greece; IT, Italy; NL, The Netherlands; NO, Norway; PL, Poland; PT, Portugal; RU, Russia; SE, Sweden; TR, Turkey; UK, age. There was no relationship between the search volume per United Kingdom. country and its population size and the number of dermatolo- gists per capita. These observations may point to a variance in four countries was genitoanal itch not among the top 20 itch-re- knowledge levels regarding Internet use across Europe. Presum- lated keywords (BL: rang 24, IT: rang 26, UK: rang 31, and NL: ably, other aspects such as the degree of urbanization, demo- rang 35). The second most often searched body region was the graphics of the population, accessibility to health care, lower extremity (19.4%; 291.70/100 000), especially the legs socioeconomic factors and cultural aspects also influence the (149.13/100 000) and feet (136.60/100 000), while the head search volume across European countries. Interestingly, we (16.5%; 248.88/100 000), particularly the scalp (103.31/100 000) recorded the highest search volume in Portugal and one of the and eyes (92.07/100 000), was the third most searched for lowest in Spain, two neighbouring southern European countries. region. Upper extremity (6.1%; 91.19/100 000) and trunk Possible reasons for these findings include linguistic and socio- (4.1%; 62.36/100 000) were the least searched for body regions. cultural differences as well as discrepancies in healthcare system In 6.0% of the cases, generalized itch was searched using differ- across the two countries. In a previous analysis of search volume ent terms (e.g. all over, diffuse). data for itch in 16 different German cities, a higher proportion of female inhabitants, lower age and smaller urban areas were Symptoms/signs Other sensory symptoms in addition to itch associated with higher search volumes.8 were found among the top 20 keywords. Burning (22.00/ In only 4/15 countries (Austria, the Netherlands, Poland, the 100 000) and stinging (4.89/100 000) were recorded in three United Kingdom) was the search volume higher in the colder countries (Table 4). months of the year (autumn/winter) compared to in the warmer As for signs, discharge was the most searched term (123.54/ months. We expected a more pronounced search volume in the 100 000), especially in connection to genital disorders, followed colder months since skin conditions that lead to itch such as xero- by erythema (66.80/100 000; Table 4). sis, atopic dermatitis and psoriasis aggravate in the winter, and this increased search volume in colder months was observed for Inter- Treatment Keywords related to treatment were also found net searches in Germany.8 However, in our study we did not con- among the top 20 itch associated search terms. What is good for trol for temperature, relative humidity, or other weather itch? (55.00/100 000) and relief (22.82/100 000) as well as cream/ parameters, which may explain the partial discrepancies between ointment (36.94/100 000) and shampoo (5.49/100 000) were our study and previous analyses. Surprisingly, in two countries searched for. Treatment options were specifically searched for (Italy, Portugal) more searches were performed in the spring/sum- urticaria (18.10/100 000) and eczema (15.33/100 000). Further- mer months. These are two of the warmest countries in Europe,13 more, various terms related to anti-acne agents (antibiotics, reti- and higher temperatures in the summer may be associated with a noids, benzoyl peroxide) and vitamin complexes were search for greater incidence of itchy conditions such as insect bites, skin (Tables S2 and S3). infestations and allergic reactions to the sun (e.g. polymorphic light eruption). Additionally, heat is a common trigger for itch, Further findings Additional keywords that could not be attrib- possibly due to activation of TRPV1, which is involved in itch uted to the abovementioned categories were among the 20 most transmission and may aggravate pre-existing conditions (e.g. urti- searched terms (Tables S2 and S3). Of interest were the 69.47/ caria, atopic dermatitis).14 Excessive sweating may also worsen itch 100 000 queries for the term dermatologist. Nocturnal itch and atopic eczema.14 In agreement, higher search volumes for itch (18.66/100 000) and scratching (12.16/100 000) as well as the have been linked to higher temperatures in a previous study.15 JEADV 2021, 35, 1362–1370 © 2020 The Authors. Journal of the European Academy of Dermatology and Venereology published by John Wiley & Sons Ltd on behalf of European Academy of Dermatology and Venereology 14683083, 2021, 6, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/jdv.17077 by Readcube (Labtiva Inc.), Wiley Online Library on [23/05/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License Internet search trends for itch in Europe 1369 The most often searched for terms associated with itch were only the top 20 itch-related keywords of each country, while in related to underlying causes, especially skin diseases. In line with previous studies the entire list of search terms that go beyond previous analyses of search volumes performed in Germany, the 20 most search terms were considered. most queries dealt with chronic inflammatory diseases (psoriasis, Interestingly, additional sensory symptoms were searched eczema, atopic dermatitis).9 Conditions leading to severe acute for in association with itch, especially ‘burning’ and ‘sting- itch such as urticaria or scabies were also frequently searched for. ing’. Such sensory qualities are often reported in neuropathic These findings reflect the high prevalence of these conditions in itch23 and in neuropathic pain conditions.24 However, these the general population. As in previous reports,9 we noticed that sensory qualities are also found in other pruritic conditions dermatological causes for the itch were searched far more often such as atopic dermatitis,25,26 psoriasis25 and chronic prur- than other possible aetiologies, such as allergic conditions and igo,27,28 suggesting a possible neuropathic component in these systemic diseases. This suggests a higher prevalence of dermato- diseases. Accordingly, the epidermal neural architecture is logical causes for itch but possibly also a general lack of knowl- altered in chronic inflammatory pruritic conditions, and cuta- edge of non-dermatological conditions that may cause itch. neous mechano- and heat-sensitive C-fibres, which transmit Most searches regarding body location concerned the geni- burning and stinging sensations in addition to itch,29 are sen- toanal region. Accordingly, high search volumes for genitoanal sitized in chronic itch conditions.30 itch were also identified in previous studies performed in Ger- This study has a few limitations. For the classification, only many, with genital and/or anal itch being the second (after the 20 most searched for keywords were considered for each ‘whole body’)9 and third (after ‘whole body’ and ‘legs’)8 most country. Therefore, the search volume for these keyword cate- searched terms related to body location. The large search volume gories could be underestimated, while data regarding keywords for genitoanal itch points to the high prevalence of genitoanal not entering the top 20 in any country were lost. pruritic conditions. These can be of diverse aetiology, including Moreover, there are difficulties that exist when translating dermatoses (e.g. eczema, psoriasis, lichen sclerosus, contact der- sensory descriptors from one language to another. An ascending matitis), infections and infestations (e.g. scabies, infestations or data-driven approach could have been adopted. Nevertheless, with parasite), anorectal conditions (e.g. haemorrhoids, anal we chose the descending method for its simplicity, and as previ- marisca), tumours (e.g. anal carcinoma, extramammary Paget ously performed,31 we observed consistent results across coun- disease) and neuropathic disorders (e.g. pudendal nerve entrap- tries, suggesting that the main itch-related terms were identified. ment).16 Previously a study confirmed that shame can trigger We did not control the data for demographic variables. This seeking online health information.17 Thus, another aspect to is important since elderly people probably consult the Internet consider is that patients may be ashamed of discussing geni- less than younger ones, while the prevalence of itch increases toanal conditions during medical consultation and may prefer with age.32 As a result, our study may not fully take into account to seek advice on the Internet for such issues. Physicians should the concerns of elderly individuals regarding their itch. We also ask more often about genitoanal itch during regular dermatolog- did not control the data for sex. A possible divergent behaviour ical visits. Genitoanal itch was also searched for in association between women and men in regard to their Internet search with other keywords such as ‘discharge’, a typical sign of geni- behaviour may thus induce bias in this study. toanal disease. Only searches in each country’s local languages were consid- The lower extremity was the second body region searched for ered, and thus searches in foreign languages within a country the most in our study. Xerosis cutis generally affects body sites were not taken into account. Therefore, immigrants who resort with few sebaceous glands, such as the legs and feet,18 which to their own language for Internet searches are likely to be may explain higher incidence rates of itch in these areas and thus underrepresented in our analysis. a high search volume for these terms. Moreover, itch on the legs Another limitation is that only searches performed with Goo- can be related to venous insufficiency and varicose veins, causing gle were considered while other search engines were disregarded. xerosis and stasis eczema,19 while itch on the feet may be associ- However, Google has a market share of 93.51% in Europe,10 and ated with dyshidrotic eczema or athlete’s foot (tinea pedis), two thus, it is likely that Google searches reflect overall Internet common skin conditions of the feet.20,21 Another important search behaviour. One exception is in Russia, where Google is body region is the scalp, which was often searched for in many used by only 52.91% of the population.33 Therefore, our data countries. Scalp pruritus poses a challenge since it may underlie from Russia should be interpreted with caution. Also, the inher- numerous distinct diseases, and its treatment is often refractory ent limitations of Google AdWords Keyword Planner should be to available treatments.22 disclosed since this tool only provides an estimation of monthly Surprisingly, compared to previous studies performed in Ger- search volumes, and Google does not divulge how this estima- many,8,9 ‘itch all over the body’ showed low search volumes in tion is performed. our European study. This may be due to different methodologies Despite the limitations of the unconventional methodology since we considered for the classification the search volumes of adopted in our study, we provided substantial insights into JEADV 2021, 35, 1362–1370 © 2020 The Authors. Journal of the European Academy of Dermatology and Venereology published by John Wiley & Sons Ltd on behalf of European Academy of Dermatology and Venereology 14683083, 2021, 6, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/jdv.17077 by Readcube (Labtiva Inc.), Wiley Online Library on [23/05/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License 1370 Pereira et al. Internet search patterns related to itch across Europe. This 16 Weisshaar E. Genitoanal pruritus. 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