The validity and reliability of patient-provided photographs for the diagnosis and severity of hand eczema—Preliminary results

Introduction: Hand eczema (HE) is a common skin disease. Although HE is a clinical diagnosis, real-time dermatological examination is often not feasible. However, data on remote assessment of HE is limited.

Objectives: To assess the criterion validity and inter- and intra-rater reliability of patient-provided photographs to diagnose and to assess the severity of HE.

Methods: Adult patients with and without HE were eligible. Presence and severity of HE (HECSI/photographic guide) were assessed by one of the two experienced raters at the clinic. Participants took four photographs of their hands (left/right, dorsal/palmar), following instructions. Afterwards, all photographs were assessed twice by four experienced raters. Criterion validity was based on the photographic assessment of the identical rater who conducted the clinical assessment. Inter- and intra-rater reliability were based on the photographic assessment of all four raters combined.

Results: In total, 50 patients were included. The sensitivity, specificity, negative and positive predictive value for diagnosing HE based on patient-provided photographs were respectively 91.9%, 92.3%, 97.1% and 80.0%. Kappa values of respectively 0.26 and 0.71 were found for the inter- and intra-rater reliability of diagnosing HE based on photographs. ICC values of 0.95, 0.96 and 0.98 were found for the criterion validity and inter- and intra-rater reliability of the photographic assessment based on the HECSI, respectively. Kappa values for the criterion validity and inter and intra-rater reliability by using the photographic guide were respectively 0.78, 0.34–0.75 and 0.72.

Conclusion: Remote assessment of HE shows excellent criterion validity for diagnosing HE and assessing its severity by using the HECSI, and substantial criterion validity for assessing the severity by using the photographic guide. Respectively fair, excellent and good inter-rater reliability, and substantial, excellent and good intra-rater reliability were found. These results indicate a potential role for remote assessment of HE in clinical and research settings.