Plane Warts: Clinical Features, Pathogenesis, Diagnostic Modalities, and Emerging Immunotherapeutic Approaches

Abstract

Plane warts (verrucae plana) are benign cutaneous lesions caused by infection with specific types of human papillomavirus (HPV), most commonly affecting children, adolescents, and immunocompromised individuals. They typically present as multiple, flat-topped papules distributed on the face, neck, and extremities, often following lines of trauma due to the Koebner phenomenon. Diagnosis is usually clinical and may be supported by dermoscopic and histopathological findings, including hypergranulosis, koilocytosis, and mild acanthosis. Although numerous treatment modalities are available, no definitive therapy eradicates HPV infection completely, and recurrence remains a major challenge. Conventional management includes destructive therapies, virucidal agents, antiproliferative drugs, and occlusive techniques. In recent years, immunotherapy has emerged as a promising strategy because of its ability to enhance cell-mediated immunity against HPV-infected keratinocytes. Various topical, systemic, and intralesional immunotherapeutic agents, including imiquimod, diphenylcyclopropenone, Candida antigen, purified protein derivative, Bacillus Calmette–Guérin vaccine, measles–mumps–rubella vaccine, and vitamin D3, have demonstrated favorable efficacy and safety profiles. This review summarizes the epidemiology, pathogenesis, clinical presentation, diagnostic methods, and currently available therapeutic options for plane warts, with particular emphasis on the evolving role of immunotherapy in achieving sustained clinical clearance and reducing recurrence.