Background: In children, psoriasis can be challenging to diagnose. Difficulties arise from differences in the clinical presentation compared with adults. Objectives: To test the diagnostic accuracy of previously agreed consensus criteria and to develop a shortlist of the best predictive diagnostic criteria for childhood psoriasis. Methods: A case–control diagnostic accuracy study in 12 UK dermatology departments (2017–2019) assessed 18 clinical criteria using blinded trained investigators. Children (< 18 years) with dermatologist-diagnosed psoriasis (cases, N = 170) or a different scaly inflammatory rash (controls, N = 160) were recruited. The best predictive criteria were identified using backward logistic regression, and internal validation was conducted using bootstrapping. Results: The sensitivity of the consensus-agreed criteria and consensus scoring algorithm was 84·6%, the specificity was 65·1% and the area under the curve (AUC) was 0·75. The seven diagnostic criteria that performed best were: (i) scale and erythema in the scalp involving the hairline, (ii) scaly erythema inside the external auditory meatus, (iii) persistent well-demarcated erythematous rash anywhere on the body, (iv) persistent erythema in the umbilicus, (v) scaly erythematous plaques on the extensor surfaces of the elbows and/or knees, (vi) well-demarcated erythematous rash in the napkin area involving the crural fold and (vii) family history of psoriasis. The sensitivity of the best predictive model was 76·8%, with specificity 72·7% and AUC 0·84. The c-statistic optimism-adjusted shrinkage factor was 0·012. Conclusions: This study provides examination- and history-based data on the clinical features of psoriasis in children and proposes seven diagnostic criteria with good discriminatory ability in secondary-care patients. External validation is now needed.
Bibliographical noteFunding Information:
sources E.B.-T. is funded through a National Institute for Health Research (NIHR) Doctoral Research Fellowship (DRF-2016-09-083). The views expressed are those of the author(s) and not necessarily those of the National Health Service, the NIHR or the Department of Health and Social Care.We would like to thank the following individuals and groups. The Test Evaluation Research Group and Dr Sarah Berhane for their advice on the diagnostic accuracy study design and the statistical analysis. Professor Hywel C. Williams for his advice on the interpretation of the data. Victoria Maddox, research assistant, for supporting the data management. All the research staff at each of the recruiting sites for their tremendous effort recruiting 330 children and young people. Dr Shithu Babu at Dorset County Hospital. Laura Wild and Melanie Pettipher, research nurses, University Hospital Coventry and Warwickshire. Jacqueline Dodds, research nurse, James Cook Hospital. Susie Hall, research nurse, Cambridge University Hospitals. Dr E. Victoria Wray at Glasgow Children?s Hospital. Teena Mackenzie, research nurse, and Melanie Westmoreland, study co-ordinator, Oxford University Hospitals. Suzanne Price, senior research nurse; Angela King, clinical trials officer; and Emma Storr, research assistant practitioner, University Hospitals Plymouth. Elena Sheldon, research nurse, Sheffield Children?s Hospital. Stefanie Townsend, research nurse, and Noreen Sheikh, research practitioner, Nottingham University Hospitals. All the children, young people and families who took part across the UK.
© 2021 The Authors. British Journal of Dermatology published by John Wiley & Sons Ltd on behalf of British Association of Dermatologists.