{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T12:13:27Z","timestamp":1785413607474,"version":"3.56.0"},"reference-count":24,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2026,4,28]],"date-time":"2026-04-28T00:00:00Z","timestamp":1777334400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003478","name":"Ministry of Health, Labour and Welfare of Japan","doi-asserted-by":"crossref","id":[{"id":"10.13039\/501100003478","id-type":"DOI","asserted-by":"crossref"}]},{"id":[{"id":"https:\/\/ror.org\/03mwa7s65","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JCM"],"abstract":"<jats:p>Background\/Objectives: The itch\u2013scratch cycle is a key driver of exacerbation in atopic dermatitis (AD) and requires objective monitoring, yet patient-reported itch scores are often unreliable in children. This study aimed to evaluate smartwatch-derived nocturnal scratching metrics as digital biomarkers of disease activity and treatment response in pediatric AD. Methods: In this prospective observational study, 50 children (median age 9 years) with physician-diagnosed AD wore an Apple Watch with the Itch Tracker application for 5\u201314 nights during initiation of topical therapy. Three scratch metrics\u2014scratch count rate (SCR), scratch duration ratio (SDR), and scratch burden index (SBI, duration \u00d7 intensity)\u2014were analyzed. Associations with clinical outcomes [Eczema Area and Severity Index (EASI), Patient-Oriented Eczema Measure (POEM)], serum thymus and activation-regulated chemokine (TARC), and itch numerical rating scale (NRS) were examined. Logistic regression models were evaluated to examine whether these metrics could identify children who achieved clinically meaningful improvement, defined as EASI-50 plus \u2265 4-point POEM reduction. Results: All scratch metrics correlated with baseline EASI (r = 0.60\u20130.64, p &lt; 0.001) and serum TARC (r = 0.58\u20130.60, p &lt; 0.001). Reductions in scratching paralleled clinical improvement (r = 0.67\u20130.71, p &lt; 0.0001). Among models, the SBI-based logistic regression demonstrated the best discriminative performance (AUC = 0.78, 95% CI: 0.64\u20130.92). Conclusions: Wearable-derived nocturnal scratching metrics showed moderate but consistent associations with disease severity and short-term improvement. Although predictive capability remains to be established, these metrics may serve as treatment-responsive digital measures. Given the cross-sectional nature of biomarker analyses and other study limitations, further prospective validation is required before clinical application in real-world pediatric AD monitoring.<\/jats:p>","DOI":"10.3390\/jcm15093380","type":"journal-article","created":{"date-parts":[[2026,4,29]],"date-time":"2026-04-29T07:43:51Z","timestamp":1777448631000},"page":"3380","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Smartwatch-Derived Nocturnal Scratching Metrics Capture Disease Activity and Severity in Pediatric Atopic Dermatitis"],"prefix":"10.3390","volume":"15","author":[{"given":"Fumiko","family":"Iwai","sequence":"first","affiliation":[{"name":"Allergy Center, National Hospital Organization (NHO) Mie National Hospital, Tsu 514-0125, Japan"},{"name":"Department of Child Health and Development, Graduate School of Medicine, Mie University, Tsu 514-0001, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Takahiro","family":"Nishida","sequence":"additional","affiliation":[{"name":"Allergy Center, National Hospital Organization (NHO) Mie National Hospital, Tsu 514-0125, Japan"},{"name":"Department of Child Health and Development, Graduate School of Medicine, Mie University, Tsu 514-0001, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rei","family":"Kanai","sequence":"additional","affiliation":[{"name":"Allergy Center, National Hospital Organization (NHO) Mie National Hospital, Tsu 514-0125, Japan"},{"name":"Department of Child Health and Development, Graduate School of Medicine, Mie University, Tsu 514-0001, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5460-9861","authenticated-orcid":false,"given":"Tomoyuki","family":"Arima","sequence":"additional","affiliation":[{"name":"Allergy Center, National Hospital Organization (NHO) Mie National Hospital, Tsu 514-0125, Japan"},{"name":"Department of Child Health and Development, Graduate School of Medicine, Mie University, Tsu 514-0001, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Takafumi","family":"Takase","sequence":"additional","affiliation":[{"name":"Allergy Center, National Hospital Organization (NHO) Mie National Hospital, Tsu 514-0125, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9250-6241","authenticated-orcid":false,"given":"Shingo","family":"Yamada","sequence":"additional","affiliation":[{"name":"Allergy Center, National Hospital Organization (NHO) Mie National Hospital, Tsu 514-0125, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mizuho","family":"Nagao","sequence":"additional","affiliation":[{"name":"Allergy Center, National Hospital Organization (NHO) Mie National Hospital, Tsu 514-0125, Japan"},{"name":"Department of Child Health and Development, Graduate School of Medicine, Mie University, Tsu 514-0001, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8002-6504","authenticated-orcid":false,"given":"Shigeru","family":"Suga","sequence":"additional","affiliation":[{"name":"Department of Child Health and Development, Graduate School of Medicine, Mie University, Tsu 514-0001, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hitoki","family":"Kubota","sequence":"additional","affiliation":[{"name":"Maruho Co., Ltd., 531-0071 Osaka, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kazuaki","family":"Okamoto","sequence":"additional","affiliation":[{"name":"Maruho Co., Ltd., 531-0071 Osaka, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Akihiko","family":"Ikoma","sequence":"additional","affiliation":[{"name":"Maruho Co., Ltd., 531-0071 Osaka, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9196-9436","authenticated-orcid":false,"given":"Takao","family":"Fujisawa","sequence":"additional","affiliation":[{"name":"Allergy Center, National Hospital Organization (NHO) Mie National Hospital, Tsu 514-0125, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,4,28]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"66","DOI":"10.1007\/s12016-025-09075-w","article-title":"Atopic Dermatitis beyond Eczema: A Review on its Systemic Impact through Pruritus and Associated Comorbidities","volume":"68","year":"2025","journal-title":"Clin. 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