Human Papillomavirus (HPV) Infections
HPV comprises a large group of small, double-stranded DNA viruses that infect squamous epithelia. Clinical manifestations depend heavily on the specific viral subtype.
Key Clinical Presentations
| Presentation | Common HPV Types |
|---|---|
| Verruca Vulgaris | 1, 2, 4, 27, 57 |
| Condyloma Acuminatum | 6, 11 |
| High-Risk (Anogenital/Oropharyngeal Ca) | 16, 18, 31, 33 |
| Epidermodysplasia Verruciformis | 5, 8 (Associated with UV radiation) |
High-Yield Pathogenesis & Management
- Viral Entry: Requires micro-abrasions to reach the basal keratinocytes.
- Oncogenesis: High-risk HPV types (16, 18) express E6 and E7 proteins, which inactivate tumor suppressor proteins p53 and pRb (retinoblastoma protein), respectively.
- Prevention: The 9-valent HPV vaccine is highly effective at preventing infections with the most common high-risk and condyloma-associated strains.
Exam Pearl:
- Condyloma Acuminatum: These are distinct from *Condyloma Lata* (a sign of Secondary Syphilis). Condyloma lata are flat, moist, and gray/white, whereas condyloma acuminata are typically exophytic, cauliflower-like growths.
- Epidermodysplasia Verruciformis: A rare genetic condition where patients have a specific defect in clearing HPV, leading to widespread, persistent infections and a very high risk of non-melanoma skin cancer.