Clinical Validation of the Updated Korean Atopic Dermatitis Diagnostic Criteria in a Hospital Setting in South Korea.

Background: Atopic dermatitis (AD) is a common chronic inflammatory skin disease whose diagnosis relies on clinical presentation and history due to the absence of definitive diagnostic tests or biomarkers. The Korean Atopic Dermatitis Association (KADA) recently updated its diagnostic criteria to enhance accuracy and applicability.

Objective: This study validates the updated KADA criteria by assessing their diagnostic performance in a clinical setting and comparing them with the previous KADA and Japanese Dermatological Association (JDA) criteria.

Methods: A multicenter, cross-sectional study was conducted with 231 AD patients and 81 non-AD controls. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), Youden's index, and error rates for the criteria and individual clinical features included were analyzed.

Results: The updated KADA criteria demonstrated the highest sensitivity (63.20%) compared to the previous KADA (61.04%) and JDA criteria (47.62%), enabling better identification of a broader range of AD phenotypes. While its specificity (82.72%) was slightly lower than that of the previous KADA (88.89%) and JDA criteria (95.06%), the updated criteria maintained a strong PPV of 91.01% and a comparable NPV of 44.10%. The Youden's index for the updated criteria was 0.459, indicating a balanced trade-off between sensitivity and specificity, and the error rate was the lowest (31.41%), underscoring its enhanced overall diagnostic accuracy.

Conclusion: The updated KADA criteria provide a practical and intuitive diagnostic tool, effectively addressing the limitations of previous criteria and improving the efficient and comprehensive diagnosis of AD, especially in those with diverse presentations.