Introduction Paediatric psoriasis is often misdiagnosed, and the overlap condition of psoriasis and atopic dermatitis (AD), known as psoriasis-dermatitis, further complicates accurate identification. Research has shown that interleukin-36 gamma (IL-36γ) measurement via tape stripping can help diagnose complex cases of psoriasis in adults. However, there are no published studies evaluating the applicability of this method in children, especially for distinguishing psoriasis from AD and the overlap condition. We aimed to assess the utility of IL-36γ measurement via tape stripping for distinguishing psoriasis from AD and for predicting the evolution of psoriasis-dermatitis in children and adolescents. Methods We conducted a cross-sectional diagnostic accuracy study in consecutive cases of psoriasis, AD, and psoriasis-dermatitis, and in healthy controls. IL-36γ concentration was measured using tape stripping and enzyme-linked immunosorbent assay (ELISA). Expert paediatric dermatologists independently confirmed the clinical diagnoses (reference standard). Results We included 11 children with psoriasis, 11 with AD, 11 with psoriasis-dermatitis, and 10 healthy controls (mean age 8.7 years, 57% female). Mean IL-36γ levels in psoriasis lesions were significantly higher than in AD lesions (144 pg/mL versus 14.4 pg/mL, P = 0.033) and in healthy controls (144 pg/mL versus 10.4 pg/mL, P = 0.037). The IL-36γ tape stripping method demonstrated a sensitivity of 91% and specificity of 91% for distinguishing psoriasis from AD, with an area under the receiver operating characteristic (ROC) curve of 0.959. The IL-36γ concentrations in participants with psoriasis-dermatitis predicted the evolution to psoriasis or dermatitis in most cases (5 out of 6, 83.3%). Conclusion IL-36γ measurement via tape stripping offers a promising method for distinguishing psoriasis from AD in children. This non-invasive approach is practical for routine clinical application and demonstrates good sensitivity and specificity, which suggests it could improve early diagnosis and patient outcomes.
