Warts are benign lesions that occur in the mucosa and skin. Warts are caused by the human papillomavirus (HPV), with over 100 types of HPV identified. HPV may occur at any site. The primary manifestations of HPV infection include common warts, genital warts, flat warts, deep palmoplantar warts (Myrmecia), focal epithelial hyperplasia, Epidermodysplasia verruciformis, and Plantar cysts. Warts may be transmitted by direct or indirect contact. Events that disrupt the normal epithelial barrier increase the likelihood of developing warts. Treatment may be difficult. Warts often resolve spontaneously within a few years. Some high-risk HPV subtypes are associated with malignancies, including types 6, 11, 16, 18, 31, and 35. Malignant transformation usually is seen in patients with genital warts and immunocompromised patients. HPV types 5, 8, 20, and 47 have oncogenic potential leading to epidermodysplasia verruciformis.
Treatment success in cutaneous warts: morphology and human papillomavirus type matter. Hogendoorn GK, Bruggink SC, deKoning MNC, et al. British Journal of Dermatology. 2018; 178(1): 253-260.
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.
