Seven diagnostic criteria provide good discriminatory ability for childhood psoriasis, according to a study published online Sept. 3 in the British Journal of Dermatology.

Esther Burden-The, B.M.B.S., from the University of Nottingham in the United Kingdom, and colleagues assessed the accuracy of previously agreed-upon consensus criteria for psoriasis diagnosis in children (<18 years) and developed a short list of the best predictive diagnostic criteria for childhood psoriasis.

The researchers report that for the agreed-upon consensus criteria, sensitivity was 84.4 percent, specificity was 65.1 percent, and the area under the curve (AUC) was 0.75. The best performing diagnostic criteria included the following: (1) scale and erythema in the scalp involving the hairline; (2) scaly erythema inside the external auditory meatus; (3) persistent well-demarcated erythematous rash anywhere on the body; (4) scaly erythematous plaques on the extensor surfaces of the elbows and/or knees; (5) persistent erythema in the umbilicus; (6) well-demarcated erythematous rash in the napkin area involving the crural folds; and (7) a family history of psoriasis. The prediction model showed 76.8 percent sensitivity, 72.7 percent specificity, and an AUC of 0.84 for two or more of the criteria. The c-statistic optimism adjusted shrinkage factor was 0.012.

"Three of the best predictive criteria involve skin in hidden sites, such as umbilicus, groin flexures and external auditory meatus," the authors write. "These criteria will therefore be helpful to prompt examination of these specific areas to determine whether a patient has psoriasis or not."

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