Developing and validating the CWARTS diagnostic tool, a novel clinical assessment and classification system for cutaneous warts.

BACKGROUND:

The clinical appearance of cutaneous warts is highly variable and not standardised.

OBJECTIVES:

The aim of this study was to develop and validate a reproducible clinical tool for the standardised assessment of cutaneous warts to distinguish these lesions accurately.

METHODS:

Nine morphological characteristics were defined and validated regarding intra- and inter-observer agreement. Based on literature and semi-structured interviews, a systematic dichotomous assessment tool, the Cutaneous WARTS diagnostic tool (CWARTS diagnostic tool) was developed. The validation consisted of two independent parts performed with photographs from the recent WARTS-2 trial. In part A, the CWARTS diagnostic tool was tested by 28 experienced physicians who assessed photographs of 10 different warts to investigate inter-observer concordance. In part B, morphological characteristics were validated by blinded and independent scoring of 299 photographs by 6 different observers. Part B also entailed re-assessment of the photographs after at least 1 week. Primary outcome measurement was the intraclass correlation coefficient (ICC).

RESULTS:

Presence of black dots (capillary thrombosis) had the greatest ICC (0.85) for inter-observer agreement in part A, followed by arrangement (0.65), presence of border erythema(0.64) and sharpness of the border (0.60). In part B results were similar for inter-observer agreement with presence of black dots having the highest ICC (0.68), followed by border erythema (0.64), arrangement (0.58) and colour (0.55). For intra-observer agreement, presence of black dots had the highest agreement (0.69), followed by presence of border erythema (0.64) and colour (0.55).

CONCLUSIONS:

The wart phenotype can be reliably assessed by the CWARTS diagnostic tool. This article is protected by copyright. All rights reserved.