Next Article in Journal
Factors Associated with Out-of-Pocket Health Expenditure in Polish Regions
Previous Article in Journal
Physicians’ Experience with COVID-19 Vaccination: A Survey Study
 
 
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Review

A Bibliometric Analysis of Atopic Dermatitis Research over the Past Three Decades and Future Perspectives

1
College of Korean Medicine, Kyung Hee University, Seoul 02447, Korea
2
Acupuncture & Meridian Science Research Center, Kyung Hee University, Seoul 02447, Korea
*
Author to whom correspondence should be addressed.
Submission received: 22 November 2021 / Revised: 10 December 2021 / Accepted: 14 December 2021 / Published: 17 December 2021

Abstract

:
Atopic dermatitis (AD) has been increasing in prevalence over the past few decades; however, AD has never been analyzed using a bibliometric approach. We searched for AD studies in the dermatology and allergy category of the Web of Science and SCOPUS databases using the keywords “atopic dermatitis”, “eczema”, and “atopy”. In total, 53,460 documents were retrieved. We analyzed annual publication trends and performed keyword and co-authorship network analyses. The annual number of AD publications has increased over the years. Asthma, food allergies, the skin barrier, IgE, and epidemiology have received extensive attention. The keywords ‘allergic rhinitis’, ‘child(ren)’, ‘quality of life’, and ‘probiotics’ have become more commonly used in recent years. AD research has been led by only a few countries, such as the USA, Germany, and the UK, and longstanding research topics such as asthma, allergy, and the immune system continue to be important. We suggest that global collaborations, research in developing countries, and research that is more holistic (thus exploring how genes, the immune system, the environment, and the microbiome together impact AD) are necessary.

1. Introduction

Atopic dermatitis (AD) is a chronic skin disease characterized by severe pruritus, recurrent eczema, sleep disruption, and skin manifestations (erythema, edema, papulation, oozing and crusting, excoriation, lichenification, and dryness). AD primarily affects infants and young children, and the prevalence (15–20% in children and 1–3% in adults) and recurrence rates are high [1]. AD reduces the quality of life [2], promotes suicidal ideation [3], and imposes significant economic burdens on patients and healthcare systems [4]. Patients with AD are hypersensitive to skin irritations, certain foods, and aero-allergens. They often develop other atopic disorders such as asthma or allergic rhinitis (the “atopic march” phenomenon [5,6]). Genetic variations, an impaired skin barrier, excessive inflammation, and allergic responses involving T-helper type 2 cytokines (e.g., interleukin [IL]-4 and IL-13), immunoglobulin E (IgE), and eosinophils have been proposed to contribute to AD pathogenesis [7]. Thus, the clinical evaluation and management of AD remain challenging [8]. Recently developed drugs (dupilumab, oluminant, and rinvoq), a growing interest in patient quality of life, and new potential therapeutic targets (such as the gut and skin microbiomes [9,10,11,12,13,14]) have motivated researchers to intensify their current approaches and explore new areas of AD research.
To achieve this goal, we strongly believe that bibliometric analysis is useful for tracking the rise and fall of research topics over time and for evaluating the impacts of publications, research affiliations, and journals. A bibliometric analysis provides an overview of a large number of publications, allows for the quantitative assessment of past research, and can be used to predict future research trends [15,16,17]). Bibliometric analysis has been used to estimate research trends in various research fields, including dermatology [17]. Bibliometrics can be utilized to analyze publication trends by country and institution and to identify the main keywords and organizations associated with AD research. However, to the best of our knowledge, AD research has not been analyzed using a bibliometric approach that lacks restrictions on research subjects (see Zhong et al. 2011 [18] for a bibliometric analysis of AD treated via Traditional Chinese Medicine).
We aimed to analyze publication and citation trends by year, country, journal, and organization; to assess trends in the most frequently studied topics; and to identify keyword and organization clusters by performing network analyses. We identified the most productive countries, affiliations, and journals and the 30 top-cited publications to highlight the progress made and the landmark studies. This will guide future research on AD.

2. Methods

Data Search and Analysis

We retrieved publications from the Web of Science and SCOPUS on 2 July 2021 using search topics including atopic dermatitis, eczema, and atopy. The retrieval strategies were TS = (“atopic dermatit*” OR atopy OR “atopic eczema”) for the Web of Science and TITLE-ABS-KEY (“atopic dermatit*” OR “atopic eczema” OR atopy) for SCOPUS. No date range limits were applied, but we restricted our search to articles written in English. The exclusion criteria were (1) articles not retrieved from the Web of Science or SCOPUS, (2) conference and meeting abstracts, (3) corrigendum documents, and (4) retracted publications. We merged the datasets from the Web of Science and SCOPUS and removed duplicates using the mergeDbSources function of R. All articles were evaluated by ISL.
Biblioshiny (https://www.bibliometrix.org/Biblioshiny.html, accessed on 5 July 2021) and the ‘bibliometrix’ R package [19] were used for the analysis of annual publication productivity (total number of publications per year), the total number of publications from each country and affiliation, the total number of citations for each article, and keyword frequency. The keyword frequency analysis was conducted for all three decades combined (1990–2020), and for each decade separately (1990–1999, 2000–2009, and 2010–2020), to identify trends in keywords over time.
We also performed a network analysis of keywords and a co-authorship-based network analysis of countries, using VOSviewer software (version 1.6.16; Centre for Science and Technology Studies, Leiden University of Leiden, Leiden, the Netherlands). Network analyses were conducted using a modularity-based clustering method. The parameters for analyses were as follows: unit of analysis = country or author keywords; fractional counting of keywords and affiliations; “layout attraction” = 3; and clustering resolution = 0.5. The minimum number of keyword occurrences was set to 5, and we excluded the keywords ‘atopic dermatitis’, ‘eczema’, ‘atopic eczema’, and ‘atopy’ from analysis. Countries that published more than five articles were included in co-authorship network analysis. All nodes were weighted by occurrence and the number of documents, respectively, to aid visualization. The total link strength and normalized citation of each country were explored to determine the influence of that country on AD research.

3. Results

3.1. Publication Productivity and Citations

A total of 53,460 articles were included after removing duplicates (n = 2342), conference papers/abstracts (n = 44), meeting abstracts (n = 7094), corrections, and retracted publications (n = 7). The annual number of publications has exhibited an upward trend since 1990 (Figure 1). The 30 most-often cited articles published between 1990 and 2020 (determined by the total citations per year) are shown in Table 1. Five studies dealt with the microbiome [20,21,22,23,24] and the skin barrier [25,26,27,28,29]; three studies explored food allergies [30,31,32]; and two studies were epidemiological in nature [33,34].
The 10 countries with the highest total numbers of publications were the USA, Germany, the UK, Japan, South Korea, China, France, Italy, the Netherlands, and Australia (Table 2). The total number of publications by affiliation (institution, hospital, or university) revealed that Northwestern University, the Karolinska Institute, the University of Copenhagen, the Technical University of Munich, Yonsei University, the University of California San Francisco, Seoul National University, Harvard University, the University of Munich, and the University of Helsinki were the most productive institutions; these are located in the USA, Sweden, Denmark, Germany, and Finland (Table 3).
The Journal of Allergy and Clinical Immunology, Allergy, Journal of Investigative and Clinical Dentistry, British Journal of Dermatology, Clinical & Experimental Allergy, International Journal of Advanced Biotechnology and Research, Journal of the American Academy of Child and Adolescent Psychiatry, Acta Dermato-Venereologica, Pediatric Allergy and Immunology, and Contact Dermatitis were the top 10 journals in terms of AD articles published (Table 4).

3.2. Keyword Frequency and Network Analyses

Keyword frequency analysis showed that the 10 most frequently used keywords were ‘asthma’, ‘allergy’, ‘child(ren)’, ‘IgE’, ‘(allergic) rhinitis’, ‘epidemiology’, ‘food allergy’, ‘(allergic) contact dermatitis’, ‘psoriasis’, ‘cytokines’, and ‘pruritus (itch)’ (Figure 2A). We also analyzed the frequency of keywords by decade as a further analysis of the changes in research trends over the past three decades. The top five most frequently used keywords between 1990 and 1999 were ‘asthma’, ‘IgE’, ‘(allergic) contact dermatitis’, ‘epidemiology’, and ‘child(ren)’ (Figure 2B). The top five most frequently used keywords between 2000 and 2009 were ‘asthma’, ‘allergy’, ‘IgE’, ‘child(ren)’, and ‘epidemiology’ (Figure 2C). The top five most frequently used keywords between 2010 and 2020 were ‘asthma’, ‘allergy’, ‘child(ren)’, ‘(allergic) rhinitis’, and ‘IgE’ (Figure 2D). These results suggest that asthma, allergy, IgE status, and childhood AD have been extensively and consistently studied over the past three decades, although the occurrence ranking of IgE decreased over that time. The ranking of the keywords ‘contact dermatitis’, ‘cytokines’, ‘IgE’, ‘prevention’, and ‘risk factor’ decreased gradually, indicating that less emphasis has been placed on those research topics by AD researchers. In contrast, the keywords ‘allergic rhinitis’, ‘child(ren)’, and ‘quality of life’ have become more popular over the decades. The keyword ‘probiotics’ entered the rankings between 2010 and 2020, revealing increasing interest in the microbiome of patients with skin disease.
Of the 1800 keywords extracted from the titles and abstracts of the studies, 96 (excluding “atopic dermatitis”, “eczema”, “atopic eczema”, and “atopy”) were included in the network analysis. Five clusters were defined based on the co-occurrences of each keyword and other keywords (Figure 3 and Table 5). Cluster 1 included 42 keywords associated with asthma, allergies, and the microbiome (e.g., ‘asthma’, ‘allergies’, ‘children’, ‘IgE’, ‘microbiota’, ‘probiotics’, and ‘allergic rhinitis’). Of the keywords in Cluster 1, ‘vitamin D’ and ‘microbiota’ were relatively new (thus more commonly employed in recent years) (pink cluster in Figure 3). Cluster 2 comprised 26 keywords associated with the skin barrier and epidemiology (e.g., ‘filaggrin’, ‘prevalence’, ‘risk factors’, ‘atopic march’, and ‘quality of life’; orange cluster in Figure 3). Of the keywords in Cluster 2, ‘meta-analysis’, ‘systematic review’, ‘phenotype’, and ‘pediatrics’ were relatively new. Cluster 3 included 14 keywords associated with allergens and skin tests (e.g., ‘patch test’, ‘food allergens’, and ‘aeroallergens’; green cluster in Figure 3). Cluster 4 included 11 keywords associated with skin contact (e.g., ‘contact dermatitis’, ‘contact allergy’, ‘patch test’, ‘occupational’, and ‘wet work’; blue cluster in Figure 3). Cluster 5 included keywords associated with non-skin diseases (‘hay fever’, ‘obesity’, and ‘rhinoconjunctivitis’; red cluster in Figure 3).

3.3. Co-Authorship Network Analysis

Of the 103 countries, 38 were included in the co-authorship analysis, and four clusters were identified (Figure 4 and Table 6). Cluster 1 included 18 countries, almost all of which are European (e.g., Germany, the UK, Italy, France, and the Netherlands; red cluster in Figure 4). Co-authorship connections were also found between European countries and Singapore, Austria, or New Zealand (Cluster 1). Cluster 2 contained 12 countries in the Americas (including the USA, Brazil, and Mexico), Canada, and East Asia (Japan, China, Hong Kong, and South Korea; green cluster in Figure 4). Cluster 3 included Turkey, Greece, and India (blue cluster in Figure 4). Cluster 4 included Switzerland and the Czech Republic (yellow cluster in Figure 4). Cluster 5 included Australia and Thailand (purple cluster in Figure 4).
Germany, the USA, the UK, Sweden, and the Netherlands exhibited the greatest normalized citation scores (326, 311, 249, 151, and 144, respectively) and total link strengths (in a slightly different order), suggesting that these countries exert the most influence on AD research in terms of both impactful papers and global collaborations that have been in operation for decades.

4. Discussion

Analysis of the 53,460 articles collected from the Web of Science and SCOPUS databases showed that the number of publications on AD has increased since 1990. The citation and keyword frequency analyses revealed that research topics such as asthma, food allergies, the skin barrier, IgE, and epidemiology have received extensive attention. The rankings of the keywords ‘contact dermatitis’, ‘cytokines’, ‘IgE’, ‘prevention’, and ‘risk factor’ decreased gradually over time, while the keywords ‘allergic rhinitis’, ‘child(ren)’, ‘quality of life’, and ‘probiotics’ have become more popular. We identified five main AD-related topics (inflammation and allergy, the skin barrier, allergens, contact dermatitis, and non-skin diseases). The USA, Germany, the UK, Japan, and South Korea were the top five most productive countries in the field of AD research. The USA, Germany, the UK, Sweden, and the Netherlands exerted the greatest influence on AD research.
The most cited article (published in 2006) addressed the prevalence of eczema in childhood [33]. That study conducted a cross-sectional questionnaire survey in 193,404 children from 37 countries (aged 6–7 years) and 304,679 children from 56 countries (aged 13–14 years). The top citation rate suggests that researchers are very interested in the different prevalences of eczema worldwide; geographical variation may be important in terms of the development of asthma and allergies. The cited authors found that the prevalences of eczema symptoms in both groups increased over time in most regions but decreased in some. An understanding of the factors promoting the decreases might allow the effective prevention and treatment of allergic diseases. The fourth most-cited article dealt with the skin microbiome [20], suggesting that microbial factors may contribute to AD development. Indeed, recent studies have suggested that an impaired skin microbiome can affect both the skin barrier [12] and the immune environment [14], eventually causing AD development and worsening the symptoms [13].

4.1. Sustainable and Newly Highlighted Research Themes

AD is frequently associated with respiratory allergic diseases, such as asthma and allergic rhinitis. The term “atopic march”, which refers to the progression of symptoms from AD to asthma to allergic rhinitis during childhood, emphasizes the strong association between AD and respiratory allergy. While the preventative effects of treating atopic march are controversial, IgE-associated allergic reactions are regarded as a key mechanism of AD, and our keyword frequency analysis emphasized the significance of the keywords ‘asthma’, ‘allergy’, and ‘IgE’ (the ranking of the latter decreased over time, but it still remains in the most recent top five). As AD is a chronic and recurrent disease, managing quality of life has become a major concern when treating AD patients. In contrast, the keywords ‘contact dermatitis’ and ‘cytokine’ dropped in the rankings, which might reflect the reduced interest of AD researchers in contact dermatitis. However, as AD patients may have an increased risk of contact sensitization, and contact dermatitis is more severe in patients with than without AD [35,36], studies that focus on the weak, sensitized skin of AD patients remain meritorious. We performed citation and keyword frequency analyses to identify topics that have recently received significant attention. These topics included the microbiome and probiotics. The roles played by the microbiological environments of the skin and other organs (e.g., the gut) remain poorly understood, as do the effects of probiotics [9]. As patients are now increasingly exposed to commercial probiotics, any abnormal changes in the composition or functions of the AD microbiome require attention, as do any effect of probiotics on AD. Such work might yield new treatments for AD.

4.2. Insufficient Global Collaborative Research Network

The co-authorship network analysis identified five clusters of countries. The UK, Germany, the USA, the Netherlands, and Sweden were influential research hubs; these countries scored highest in terms of total link strength. On the other hand, Japan and South Korea were both very productive, but the citation scores were rather low, suggesting that research quality requires improvement. The clusters consisted mainly of neighboring countries or those on the same continent, indicating that there are only a few intercontinental global collaborations in AD research. Building an international network to strengthen the research community, and enhance research quality and diversity, could be valuable.

4.3. Future Directions

It is important to note that although AD is a worldwide disease, research thereon has mostly been performed in a few developed countries and may not be transferable to AD patients in developing countries. Thus, AD patients in developing countries might not benefit from the research findings, even though studies have shown an increasing prevalence of AD in such countries [33,37]. For example, the mechanisms and risk factors in developing countries could be different to those in developed countries. Therefore, it is necessary to train healthcare providers and improve patient access to healthcare resources, as well as to facilitate AD research, in developing countries.
In addition to skin barrier impairments in the context of food and skin contact, AD is also related to environmental factors (e.g., climate, UV light exposure, temperature, and air pollution), diet, and the gut and skin microbiomes [38]. We suggest that collaborations among epidemiologists, basic scientists, clinical researchers, microbiologists, and pharmaceutical industrialists, and the establishment of international research networks, will improve our knowledge of the causes of AD and enable us to treat AD more effectively in the future.

4.4. Limitations

This study had several limitations. The quality of the publications was not considered, and all authors were treated equally regardless of their contribution to the work (e.g., first, corresponding, or co-author). Finally, some institutes might have close relationships (e.g., the Karolinska Institute and Karolinska University Hospital), although we changed or combined organization names to account for this.

5. Conclusions

In conclusion, the countries leading AD research have been the USA, Germany, the UK, Japan, South Korea, Sweden, and the Netherlands. The most prevalent research themes have been ‘asthma’, ‘allergy’, ‘child(ren)’, ‘IgE’, ‘(allergic) rhinitis’, ‘epidemiology’, ‘food allergy’, ‘(allergic) contact dermatitis’, ‘psoriasis’, ‘cytokines’, and ‘pruritus (itch)’. Five research topic clusters were identified (inflammation and allergy, skin barrier, allergens, contact dermatitis, and non-skin diseases). Our analyses identified global temporal trends and the current status of AD research and suggest possible future research hotspots. For example, the lack of international research networks and interdisciplinary studies, and the few publications from developing countries, are limitations of AD research. We suggest that global collaborations, research in developing countries, and research on multiple factors (genes, the immune system, the environment, and the microbiome) are required in the field of AD research.

Author Contributions

D.K. and I.-S.L. carried out the data extraction and bibliometric analysis, prepared the first draft. Y.C. and H.-J.P. interpreted the data, and ISL finalized the manuscript. Y.C., H.-J.P. and I.-S.L. performed the critical revision of the manuscript for important intellectual content. All authors have read and agreed to the published version of the manuscript.

Funding

This work was supported by the National Research Foundation of Korea and funded by the Korean government (NRF-2020R1A4A1018598, 2021R1F1A1050116) and a grant from Kyung Hee University in 2020 (KHU-20201228).

Data Availability Statement

All data are available upon request to the corresponding author.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Nutten, S. Atopic dermatitis: Global epidemiology and risk factors. Ann. Nutr. Metab. 2015, 66 (Suppl. S1), 8–16. [Google Scholar] [CrossRef] [PubMed]
  2. Blome, C.; Radtke, M.A.; Eissing, L.; Augustin, M. Quality of Life in Patients with Atopic Dermatitis: Disease Burden, Measurement, and Treatment Benefit. Am. J. Clin. Dermatol. 2016, 17, 163–169. [Google Scholar] [CrossRef] [PubMed]
  3. Pompili, M.; Bonanni, L.; Gualtieri, F.; Trovini, G.; Persechino, S.; Baldessarini, R.J. Suicidal risks with psoriasis and atopic dermatitis: Systematic review and meta-analysis. J. Psychosom. Res. 2021, 141, 110347. [Google Scholar] [CrossRef] [PubMed]
  4. Chung, J.; Simpson, E.L. The socioeconomics of atopic dermatitis. Ann. Allergy Asthma Immunol. 2019, 122, 360–366. [Google Scholar] [CrossRef] [Green Version]
  5. Bantz, S.K.; Zhu, Z.; Zheng, T. The Atopic March: Progression from Atopic Dermatitis to Allergic Rhinitis and Asthma. J. Clin. Cell. Immunol. 2014, 5, 202. [Google Scholar] [CrossRef] [Green Version]
  6. Hill, D.A.; Spergel, J.M. The atopic march: Critical evidence and clinical relevance. Ann. Allergy Asthma Immunol. 2018, 120, 131–137. [Google Scholar] [CrossRef] [Green Version]
  7. Fiset, P.O.; Leung, D.Y.; Hamid, Q. Immunopathology of atopic dermatitis. J. Allergy Clin. Immunol. 2006, 118, 287–290. [Google Scholar] [CrossRef]
  8. Lio, P.A.; Lee, M.; LeBovidge, J.; Timmons, K.G.; Schneider, L. Clinical management of atopic dermatitis: Practical highlights and updates from the atopic dermatitis practice parameter 2012. J. Allergy Clin. Immunol. Pract. 2014, 2, 361–369. [Google Scholar] [CrossRef]
  9. Fang, Z.; Li, L.; Zhang, H.; Zhao, J.; Lu, W.; Chen, W. Gut Microbiota, Probiotics, and Their Interactions in Prevention and Treatment of Atopic Dermatitis: A Review. Front. Immunol. 2021, 12, 720393. [Google Scholar] [CrossRef]
  10. Lee, S.Y.; Lee, E.; Park, Y.M.; Hong, S.J. Microbiome in the Gut-Skin Axis in Atopic Dermatitis. Allergy Asthma Immunol. Res. 2018, 10, 354–362. [Google Scholar] [CrossRef]
  11. Salem, I.; Ramser, A.; Isham, N.; Ghannoum, M.A. The Gut Microbiome as a Major Regulator of the Gut-Skin Axis. Front. Microbiol. 2018, 9, 1459. [Google Scholar] [CrossRef] [Green Version]
  12. Grice, E.A.; Kong, H.H.; Conlan, S.; Deming, C.B.; Davis, J.; Young, A.C.; Program, N.C.S.; Bouffard, G.G.; Blakesley, R.W.; Murray, P.R.; et al. Topographical and temporal diversity of the human skin microbiome. Science 2009, 324, 1190–1192. [Google Scholar] [CrossRef] [Green Version]
  13. Kennedy, E.A.; Connolly, J.; Hourihane, J.O.; Fallon, P.G.; McLean, W.H.I.; Murray, D.; Jo, J.H.; Segre, J.A.; Kong, H.H.; Irvine, A.D. Skin microbiome before development of atopic dermatitis: Early colonization with commensal staphylococci at 2 months is associated with a lower risk of atopic dermatitis at 1 year. J. Allergy Clin. Immunol. 2017, 139, 166–172. [Google Scholar] [CrossRef] [Green Version]
  14. Nakatsuji, T.; Chen, T.H.; Narala, S.; Chun, K.A.; Two, A.M.; Yun, T.; Shafiq, F.; Kotol, P.F.; Bouslimani, A.; Melnik, A.V.; et al. Antimicrobials from human skin commensal bacteria protect against Staphylococcus aureus and are deficient in atopic dermatitis. Sci. Transl. Med. 2017, 9, 378. [Google Scholar] [CrossRef] [Green Version]
  15. Lee, I.S.; Lee, H.; Chen, Y.H.; Chae, Y. Bibliometric Analysis of Research Assessing the Use of Acupuncture for Pain Treatment Over the Past 20 Years. J. Pain Res. 2020, 13, 367–376. [Google Scholar] [CrossRef] [Green Version]
  16. Park, H.; Lee, I.S.; Lee, H.; Chae, Y. Bibliometric Analysis of Moxibustion Research Trends over the Past 20 Years. J. Clin. Med. 2020, 9, 1254. [Google Scholar] [CrossRef]
  17. Gantenbein, L.; Arora, P.; Navarini, A.; Brandt, O.; Mueller, S.M. Global publication productivity in dermatology: A bibliometric description of the past and estimation of the future. J. Eur. Acad. Dermatol. Venereol. 2021, 35, 1424–1433. [Google Scholar] [CrossRef]
  18. Zhong, Q.; Luo, H.Y.; Chang, Y.Q. A Bibliometrics Analysis of Atopic Dermatitis by Traditional Chinese Medicine. J. Hubei Univ. Natl. 2011. Available online: https://en.cnki.com.cn/Article_en/CJFDTotal-FBMZ201102015.htm (accessed on 20 November 2021).
  19. Aria, M.; Cuccurullo, C. bibliometrix: An R-tool for comprehensive science mapping analysis. J. Informetr. 2017, 11, 959–975. [Google Scholar] [CrossRef]
  20. Grice, E.A.; Segre, J.A. The skin microbiome. Nat. Rev. Microbiol. 2011, 9, 244–253. [Google Scholar] [CrossRef]
  21. Roberfroid, M.; Gibson, G.R.; Hoyles, L.; McCartney, A.L.; Rastall, R.; Rowland, I.; Wolvers, D.; Watzl, B.; Szajewska, H.; Stahl, B.; et al. Prebiotic effects: Metabolic and health benefits. Br. J. Nutr. 2010, 104 (Suppl. S2), S1–S63. [Google Scholar] [CrossRef] [Green Version]
  22. Kong, H.H.; Oh, J.; Deming, C.; Conlan, S.; Grice, E.A.; Beatson, M.A.; Nomicos, E.; Polley, E.C.; Komarow, H.D.; NISC Comparative Sequence Program; et al. Temporal shifts in the skin microbiome associated with disease flares and treatment in children with atopic dermatitis. Genome Res. 2012, 22, 850–859. [Google Scholar] [CrossRef] [Green Version]
  23. Ege, M.J.; Mayer, M.; Normand, A.C.; Genuneit, J.; Cookson, W.O.; Braun-Fahrlander, C.; Heederik, D.; Piarroux, R.; von Mutius, E.; The GABRIELA Transregio 22 Study Group. Exposure to environmental microorganisms and childhood asthma. N. Engl. J. Med. 2011, 364, 701–709. [Google Scholar] [CrossRef]
  24. Kalliomaki, M.; Salminen, S.; Arvilommi, H.; Kero, P.; Koskinen, P.; Isolauri, E. Probiotics in primary prevention of atopic disease: A randomised placebo-controlled trial. Lancet 2001, 357, 1076–1079. [Google Scholar] [CrossRef]
  25. Palmer, C.N.; Irvine, A.D.; Terron-Kwiatkowski, A.; Zhao, Y.; Liao, H.; Lee, S.P.; Goudie, D.R.; Sandilands, A.; Campbell, L.E.; Smith, F.J.; et al. Common loss-of-function variants of the epidermal barrier protein filaggrin are a major predisposing factor for atopic dermatitis. Nat. Genet. 2006, 38, 441–446. [Google Scholar] [CrossRef]
  26. Soumelis, V.; Reche, P.A.; Kanzler, H.; Yuan, W.; Edward, G.; Homey, B.; Gilliet, M.; Ho, S.; Antonenko, S.; Lauerma, A.; et al. Human epithelial cells trigger dendritic cell mediated allergic inflammation by producing TSLP. Nat. Immunol. 2002, 3, 673–680. [Google Scholar] [CrossRef]
  27. Ong, P.Y.; Ohtake, T.; Brandt, C.; Strickland, I.; Boguniewicz, M.; Ganz, T.; Gallo, R.L.; Leung, D.Y. Endogenous antimicrobial peptides and skin infections in atopic dermatitis. N. Engl. J. Med. 2002, 347, 1151–1160. [Google Scholar] [CrossRef] [Green Version]
  28. Proksch, E.; Brandner, J.M.; Jensen, J.M. The skin: An indispensable barrier. Exp. Dermatol. 2008, 17, 1063–1072. [Google Scholar] [CrossRef]
  29. Nestle, F.O.; Di Meglio, P.; Qin, J.Z.; Nickoloff, B.J. Skin immune sentinels in health and disease. Nat. Rev. Immunol. 2009, 9, 679–691. [Google Scholar] [CrossRef] [Green Version]
  30. Du Toit, G.; Roberts, G.; Sayre, P.H.; Bahnson, H.T.; Radulovic, S.; Santos, A.F.; Brough, H.A.; Phippard, D.; Basting, M.; Feeney, M.; et al. Randomized trial of peanut consumption in infants at risk for peanut allergy. N. Engl. J. Med. 2015, 372, 803–813. [Google Scholar] [CrossRef] [Green Version]
  31. Panel, N.I.-S.E.; Boyce, J.A.; Assa’ad, A.; Burks, A.W.; Jones, S.M.; Sampson, H.A.; Wood, R.A.; Plaut, M.; Cooper, S.F.; Fenton, M.J.; et al. Guidelines for the diagnosis and management of food allergy in the United States: Report of the NIAID-sponsored expert panel. J. Allergy Clin. Immunol. 2010, 126, S1–S58. [Google Scholar] [CrossRef] [Green Version]
  32. Sampson, H.A. Update on food allergy. J. Allergy Clin. Immunol. 2004, 113, 805–819. [Google Scholar] [CrossRef] [PubMed]
  33. Asher, M.I.; Montefort, S.; Bjorksten, B.; Lai, C.K.; Strachan, D.P.; Weiland, S.K.; Williams, H.; Group, I.P.T.S. Worldwide time trends in the prevalence of symptoms of asthma, allergic rhinoconjunctivitis, and eczema in childhood: ISAAC Phases One and Three repeat multicountry cross-sectional surveys. Lancet 2006, 368, 733–743. [Google Scholar] [CrossRef]
  34. Beasley, R. Worldwide variation in prevalence of symptoms of asthma, allergic rhinoconjunctivitis, and atopic eczema: ISAAC. The International Study of Asthma and Allergies in Childhood (ISAAC) Steering Committee. Lancet 1998, 351, 1225–1232. [Google Scholar] [CrossRef]
  35. Simonsen, A.B.; Johansen, J.D.; Deleuran, M.; Mortz, C.G.; Sommerlund, M. Contact allergy in children with atopic dermatitis: A systematic review. Br. J. Dermatol. 2017, 177, 395–405. [Google Scholar] [CrossRef]
  36. Hamann, C.R.; Hamann, D.; Egeberg, A.; Johansen, J.D.; Silverberg, J.; Thyssen, J.P. Association between atopic dermatitis and contact sensitization: A systematic review and meta-analysis. J. Am. Acad. Dermatol. 2017, 77, 70–78. [Google Scholar] [CrossRef]
  37. Williams, H.; Stewart, A.; von Mutius, E.; Cookson, W.; Anderson, H.R.; International Study of Asthma and Allergies in Childhood (ISAAC) Phase One and Three Study Groups. Is eczema really on the increase worldwide? J. Allergy Clin. Immunol. 2008, 121, 947–954.e15. [Google Scholar] [CrossRef]
  38. Flohr, C.; Mann, J. New insights into the epidemiology of childhood atopic dermatitis. Allergy 2014, 69, 3–16. [Google Scholar] [CrossRef]
Figure 1. The total number of publications per year during the period 1990–2020.
Figure 1. The total number of publications per year during the period 1990–2020.
Healthcare 09 01749 g001
Figure 2. The most frequently used keywords ordered by occurrence in the period 1990–2020. (A) Number of the most frequently used keywords from 1990 to 2020 from publications in AD research. During the past three decades, ‘Asthma’, ‘Allergy’, ‘Child(ren)’, ‘IgE’, and ‘(Allergic) Rhinitis’ have been the most commonly used keywords; (B) Number of the most frequently used keywords from 1990 to 1999. During the early years of AD research, the top five most frequently used keywords were ‘Asthma’, ‘IgE’, ‘(Allergic) Contact Dermatitis’, ‘Epidemiology’, and ‘Child(ren)’; (C) Number of the most frequently used keywords from 2020 to 2009. The keyword ‘Child(ren)’ had become more popular than the previous decade; (D) Number of the most frequently used keywords from 2010 to 2020.
Figure 2. The most frequently used keywords ordered by occurrence in the period 1990–2020. (A) Number of the most frequently used keywords from 1990 to 2020 from publications in AD research. During the past three decades, ‘Asthma’, ‘Allergy’, ‘Child(ren)’, ‘IgE’, and ‘(Allergic) Rhinitis’ have been the most commonly used keywords; (B) Number of the most frequently used keywords from 1990 to 1999. During the early years of AD research, the top five most frequently used keywords were ‘Asthma’, ‘IgE’, ‘(Allergic) Contact Dermatitis’, ‘Epidemiology’, and ‘Child(ren)’; (C) Number of the most frequently used keywords from 2020 to 2009. The keyword ‘Child(ren)’ had become more popular than the previous decade; (D) Number of the most frequently used keywords from 2010 to 2020.
Healthcare 09 01749 g002
Figure 3. Network analysis of author keywords during the period 1990–2020. Keywords used more than five times were included in the network analysis; the keywords ‘atopic dermatitis’, ‘eczema’, ‘atopic eczema’, and ‘atopy’ were excluded. The following parameters for VOSviewer were used: layout attraction of 3, clustering resolution of 0.5, visualization scale of 1.3, and size variation of 0.6; node sizes were weighted based on the keyword frequencies in the clusters.
Figure 3. Network analysis of author keywords during the period 1990–2020. Keywords used more than five times were included in the network analysis; the keywords ‘atopic dermatitis’, ‘eczema’, ‘atopic eczema’, and ‘atopy’ were excluded. The following parameters for VOSviewer were used: layout attraction of 3, clustering resolution of 0.5, visualization scale of 1.3, and size variation of 0.6; node sizes were weighted based on the keyword frequencies in the clusters.
Healthcare 09 01749 g003
Figure 4. Co-authorship networks of countries during the period 1990–2020. Organizations that published more than five articles were included in the co-authorship network analysis. The following parameters for VOSviewer were used: layout attraction of 3, clustering resolution of 0.5, visualization scale of 1.3, and size variation of 0.6; the node sizes were weighted based on the number of documents. Five clusters were identified. The USA, the UK, and Germany were central hubs of collaborative research.
Figure 4. Co-authorship networks of countries during the period 1990–2020. Organizations that published more than five articles were included in the co-authorship network analysis. The following parameters for VOSviewer were used: layout attraction of 3, clustering resolution of 0.5, visualization scale of 1.3, and size variation of 0.6; the node sizes were weighted based on the number of documents. Five clusters were identified. The USA, the UK, and Germany were central hubs of collaborative research.
Healthcare 09 01749 g004
Table 1. The top 30 most cited papers on atopic dermatitis over the past 30 years.
Table 1. The top 30 most cited papers on atopic dermatitis over the past 30 years.
No.ArticlesTotal Citation/YearTopic
1Worldwide time trends in the prevalence of symptoms of asthma, allergic rhinoconjunctivitis, and eczema in childhood: ISAAC Phases One and Three repeat multicountry cross-sectional surveys161.56AD epidemiology
2Randomized Trial of Peanut Consumption in Infants at Risk for Peanut Allergy134.29Food allergy
3Global epidemiology of psoriasis: a systematic review of incidence and prevalence132.89Other disease (psoriasis)
4The skin microbiome118.82Microbiome
5Two Phase 3 Trials of Dupilumab versus Placebo in Atopic Dermatitis117.5Clinical trial
6Unbiased classification of sensory neuron types by large-scale single-cell RNA sequencing114.86Itch
7Common loss-of-function variants of the epidermal barrier protein filaggrin are a major predisposing factor for atopic dermatitis114.19Skin barrier
8Guidelines for the diagnosis and management of food allergy in the United States: report of the NIAID-sponsored expert panel112.33Food allergy
9Worldwide variation in prevalence of symptoms of asthma, allergic rhinoconjunctivitis, and atopic eczema: ISAAC111AD epidemiology
10Dermatology Life Quality Index (DLQI)—a simple practical measure for routine clinical use98.75Questionnaire
11Prebiotic effects: metabolic and health benefits 93.67Microbiome
12Atopic Dermatitis91Review
13International Study of Asthma and Allergies in Childhood (ISAAC): rationale and methods88.70Study introduction
14The effect of infections on susceptibility to autoimmune and allergic diseases85.65Infection
15Temporal shifts in the skin microbiome associated with disease flares and treatment in children with atopic dermatitis81.2Microbiome
16Exposure to Environmental Microorganisms and Childhood Asthma81.09Microbiome
17Revised nomenclature for allergy for global use: Report of the Nomenclature Review Committee of the World Allergy Organization, October 200379.89Nomenclature
18Probiotics in primary prevention of atopic disease: a randomised placebo-controlled trial79.76Microbiome
19The development of allergic inflammation75.07Review
20Human epithelial cells trigger dendritic cell–mediated allergic inflammation by producing TSLP70.75Skin barrier
21Eosinophilic esophagitis in children and adults: a systematic review and consensus recommendations for diagnosis and treatment69.53Other disease (eosinophilic esophagitis)
22Pathogenesis and clinical features of psoriasis69.07Other disease (psoriasis)
23Endogenous Antimicrobial Peptides and Skin Infections in Atopic Dermatitis66.15Skin barrier
24The skin: an indispensable barrier62.93Skin barrier
25A revised nomenclature for allergy. An EAACI position statement from the EAACI nomenclature task force58.71Nomenclature
26Impaired TH17 cell differentiation in subjects with autosomal dominant hyper-IgE syndrome58.21Other disease (hyper-IgE syndrome)
27IL-22 increases the innate immunity of tissues56.56Interleukin
28New insights into atopic dermatitis55.89Review
29Skin immune sentinels in health and disease55.31Skin barrier
30Update on food allergy54.28Food allergy
Table 2. The total number of publications from the top 30 countries during the period 1990–2020.
Table 2. The total number of publications from the top 30 countries during the period 1990–2020.
No.CountryTotal Publications
1USA31,851
2Germany15,071
3UK11,611
4Japan11,500
5South Korea9810
6China8460
7France7343
8Italy6314
9Netherlands5604
10Australia5162
11Sweden4859
12Spain4116
13Canada4071
14Denmark3837
15Finland3033
16Switzerland2815
17Turkey2651
18Poland2414
19Brazil2031
20Austria1468
21Iran1424
22India1374
23Norway1280
24Belgium1271
25Singapore1130
26Israel1084
27Ireland955
28New Zealand952
29Greece764
30Portugal757
Table 3. The total number of publications from the top 30 affiliations during the period 1990–2020.
Table 3. The total number of publications from the top 30 affiliations during the period 1990–2020.
No.Affiliation (Country)Total Publications
1Northwestern Univ. (USA)1371
2Karolinska Inst. (Sweden)1285
3Univ. Copenhagen (Denmark)1026
4Tech. Univ. Munich (Germany)819
5Yonsei Univ. (South Korea)776
6Univ. California San Francisco (USA)772
7Seoul Natl. Univ. (South Korea)756
8Harvard Univ. (USA)724
9Univ. Munich (Germany)710
10Univ. Helsinki (Finland)675
11Johns Hopkins Univ. (USA)630
12Univ. Pennsylvania (USA)627
13Icahn Sch. of Med. at Mountain Sinai (USA)624
14Univ. Southampton (UK)588
15Univ. Groningen (Netherlands)585
16King’s college London (UK)582
17Univ. California San Diego (USA)580
18Hannover Med. Sch. (Germany)568
19Kyung Hee Uni. (South Korea)568
20Chinese Univ. Hong Kong (Hong Kong)567
21Univ. Melbourne (Australia)566
22Univ. Western Australia
(Australia)
551
23Univ. Amsterdam
(Netherlands)
546
24Oregon Health and Science Univ. (USA)535
25Univ. Nottingham (UK)505
26Univ. Colorado (USA)495
27Univ. Toronto (Canada)482
28Univ. Manchester (UK)473
29Univ. Med. Center Utrecht (Netherlands)440
30Univ. Utrecht (Netherlands)437
Table 4. The top 30 journals in terms of atopic dermatitis publications over the past 30 years.
Table 4. The top 30 journals in terms of atopic dermatitis publications over the past 30 years.
No.JournalTotal PublicationsNo.JournalTotal Publications
1Journal of Allergy and Clinical Immunology326916Current Opinion in Allergy and Clinical Immunology469
2Allergy252817Revue Française d’Allergologie466
3Journal of Investigative and Clinical Dentistry239518Archives of Dermatological Research462
4British Journal of Dermatology210519Der Hautarzt429
5Clinical & Experimental Allergy187820PLOS One425
6International Journal of Advanced Biotechnology and Research131421Veterinary Dermatology418
7Journal of the American Academy of Child and Adolescent Psychiatry118222Pediatric Dermatology415
8Acta Dermato-Venereologica104623Allergologie400
9Pediatric Allergy and Immunology99924American Journal of Respiratory and Critical Care Medicine399
10Contact Dermatitis96925The Journal of Dermatology393
11Annals of Allergy, Asthma and Immunology77226European Respiratory Journal355
12International Archives of Allergy and Immunology68627Journal der Deutschen Dermatologischen Gesellschaft339
13Journal of the European Academy of Dermatology and Venereology67328Dermatology324
14Journal of Dermatological Case Reports66029Annales de Dermatologie et de Vénéréologie319
15Experimental Dermatology65530Journal of Immunology314
Table 5. Top 10 keywords in each cluster based on keyword network analysis (sorted by total link strength).
Table 5. Top 10 keywords in each cluster based on keyword network analysis (sorted by total link strength).
ClusterKeywordsTotal Link StrengthOccurrencesAverage Publication Year
Cluster 1Asthma1421542010
Allergies1141242010
Children911002009
IgE47542008
Probiotics40472010
Allergic Rhinitis39422012
Dermatitis29342011
Sensitization26272009
Rhinitis22232011
Allergic Diseases22252010
Cluster 2Epidemiology51602006
Filaggrin22242012
Prevalence19232009
Risk Factors17212009
Skin Barrier13132011
Treatment13152010
Meta-Analysis11112015
Quality of Life11122013
Diagnosis11112005
Severity882011
Cluster 3Patch Test75972006
Food Allergens66732010
Aeroallergens26272006
Skin Prick Test22242006
Urticaria8102006
Oral Food Challenge882009
Cow’s Milk Allergy792007
Anaphylaxis782009
Food782009
Malassezia672005
Cluster 4Allergic Contact Dermatitis28322010
Contact Allergy472007
Contact Dermatitis14182012
Contact Urticaria262000
Cosmetics662017
Hand Eczema27312005
Immunology352007
Irritant Contact Dermatitis17172011
Occupational10102002
Therapy352008
Cluster 5Hay Fever17172007
Obesity452013
Rhinoconjunctivitis882011
Table 6. Top 10 countries in each cluster based on co-authorship network analysis during the period 1990–2020 (sorted by total link strength).
Table 6. Top 10 countries in each cluster based on co-authorship network analysis during the period 1990–2020 (sorted by total link strength).
ClusterCountriesTotal Link StrengthNormalized Citation
Cluster 1United Kingdom68248.76
Germany65326.07
Netherlands34143.96
Sweden33150.96
Italy28110.06
Austria1631.75
Finland15141.94
France1473.85
Denmark1498.86
Belgium1254.05
Cluster 2United States64311.38
Canada1946.66
Spain1341.09
Japan1048.08
Brazil719.07
Mexico633.99
China517.47
Argentina58.10
Colombia35.07
Hong Kong312.95
Cluster 3Greece315.51
India22.27
Turkey112.69
Cluster 4Switzerland2585.53
Czech Republic12.92
Cluster 5Australia30114.33
Thailand22.62
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Share and Cite

MDPI and ACS Style

Kim, D.; Chae, Y.; Park, H.-J.; Lee, I.-S. A Bibliometric Analysis of Atopic Dermatitis Research over the Past Three Decades and Future Perspectives. Healthcare 2021, 9, 1749. https://0-doi-org.brum.beds.ac.uk/10.3390/healthcare9121749

AMA Style

Kim D, Chae Y, Park H-J, Lee I-S. A Bibliometric Analysis of Atopic Dermatitis Research over the Past Three Decades and Future Perspectives. Healthcare. 2021; 9(12):1749. https://0-doi-org.brum.beds.ac.uk/10.3390/healthcare9121749

Chicago/Turabian Style

Kim, Dongwon, Younbyoung Chae, Hi-Joon Park, and In-Seon Lee. 2021. "A Bibliometric Analysis of Atopic Dermatitis Research over the Past Three Decades and Future Perspectives" Healthcare 9, no. 12: 1749. https://0-doi-org.brum.beds.ac.uk/10.3390/healthcare9121749

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop