Identifying the best predictive diagnostic criteria for psoriasis in children (<18 years): A UK multicenter case-control diagnostic accuracy study (DIPSOC study)

Background In children, psoriasis can be challenging to diagnose. Difficulties arise from differences in the clinical presentation compared to adults. Objectives To test the diagnostic accuracy of previously agreed consensus criteria and develop a shortlist of 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 ( Results The sensitivity of the consensus agreed criteria and consensus scoring algorithm was 84.4%, specificity was 65.1% and area under the curve (AUC) 0.75. Seven diagnostic criteria which 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) scaly erythematous plaques on the extensor surfaces of the elbows and/or knees; v) persistent erythema in the umbilicus; vi) well demarcated erythematous rash in the napkin area involving the crural folds; vii) family history of psoriasis. Sensitivity of the best predictive model was 76.8%, 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.