Types
- Low-risk HPV types 6 and 11
- Anogenital warts (condylomata acuminata)
- High-risk HPV types 16, 18, 31, and 33
- Cervical cancer (responsible for 70% of cases)
- High risk of anogenital, oral, and oropharyngeal squamous cell carcinoma
- HPV types 1, 2, and 4: cause skin warts, such as common warts (verruca vulgaris) and plantar warts (myrmecias)
Pathology
- HPV infect stratum basale, where epithelial cells are replicating
- Epidermal hyperplasia and hyperkeratosis
- Koilocytes
- Pathognomonic of an infection with HPV
- Dysplastic squamous cells characterized by well-defined, clear, balloon-like, perinuclear halo and hyperchromasia
Nonanogenital manifestations
Common warts (verruca vulgaris)
- Pathogen: particularly low-risk HPV types 2 and 4
- Clinical features
- Lesions are plaques or papules
- Skin-colored or whitish
- Usually firm, often with a rough and scaly surface
- Sometimes have a cauliflower-like appearance
Treatment
- Imiquimod
- Local treatment
- Mechanism of action: toll-like receptor 7 agonist → activates immune cells (i.e., macrophages, monocytes, dendritic cells)
- Indication: actinic keratoses, superficial basal cell carcinomas, herpes simplex infections, and anogenital warts
- Adverse effects: burning pain at application site, dermal rash, pruritus