Developing and validating the Cutaneous WARTS (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 standardized. OBJECTIVES: To develop and validate a reproducible clinical tool for the standardized assessment of cutaneous warts to distinguish these lesions accurately. METHODS: Nine morphological characteristics were defined and validated regarding intra- and interobserver agreement. Based on literature and semistructured interviews, a systematic dichotomous assessment tool, the Cutaneous WARTS (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 interobserver concordance. In part B, morphological characteristics were validated by masked and independent scoring of 299 photographs by six different observers. Part B also entailed reassessment of the photographs after at least 1 week. The primary outcome measurement was the intraclass correlation coefficient (ICC). RESULTS: Presence of black dots (capillary thrombosis) had the greatest ICC (0·85) for interobserver 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 interobserver 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 intraobserver agreement, presence of black dots had the highest agreement (0·70), followed by presence of border erythema (0·694) and colour (0·59). CONCLUSIONS: Wart phenotype can be reliably assessed using the CWARTS diagnostic tool.

Morphological characteristics and human papillomavirus genotype predict the treatment response in cutaneous warts.

BACKGROUND: Cutaneous warts have a cure rate after therapy of no more than approximately 50%. Recently, we developed and validated a standard assessment tool for warts (Cutaneous WARTS diagnostic tool, CWARTS) based on phenotypical characteristics. OBJECTIVES: To assess whether patient and morphological wart characteristics predict the human papillomavirus (HPV) type in a specific wart and whether these characteristics as well as the HPV type predict a favourable treatment response. METHODS: Photographs were used to score nine morphological wart characteristics using the newly developed CWARTS tool. Genotyping of 23 wart-associated HPV types was performed using the hyperkeratotic skin lesion-polymerase chain reaction/multiplex genotyping assay. The results were correlated with a favourable response to treatment with monochloroacetic acid, cryotherapy or a combination of cryotherapy and salicylic acid. Odds ratios were calculated using logistic regression in a generalized estimating equations model. RESULTS: Black dots (capillary thrombosis) strongly predicted the presence of any HPV type in a wart. From all characteristics tested, the HPV type most strongly predicted the treatment response when the warts were treated with monochloroacetic acid or a combination of cryotherapy and salicylic acid with a significantly decreased treatment response if the warts contained HPVs of the alpha genus (HPV2, HPV27 or HPV57). When cryotherapy alone was used for common warts, HPV type did not play a role, but cryotherapy was less effective in the presence of callus and when the wart was located deeper in the skin. CONCLUSIONS: Morphological characteristics of the warts and the HPV genotype influence treatment outcome and thus potentially influence future treatment decisions for common and plantar warts.