Chapter 15: Viral Skin Infections

The first section addresses human papillomavirus infection, which manifests as warts through infection of epithelial cells and presents in multiple morphological variants including common warts with characteristic thrombosed capillaries, flat warts on facial surfaces, filiform warts with fingerlike projections, and plantar warts that develop at pressure-bearing sites on the feet. While warts lack true roots despite common misconceptions, they can be differentiated from similar lesions by the absence of skin line continuity and the presence of bleeding black dots upon gentle paring. Management emphasizes that spontaneous resolution occurs in a substantial proportion of cases within two years, with first-line interventions including salicylic acid applications and cryotherapy using liquid nitrogen, while refractory cases may require topical chemical agents, intralesional immunotherapies, or specialized dermatological procedures. The second section focuses on herpes simplex virus infections caused by two distinct strains with characteristic anatomical tropism, establishing lifelong latency within sensory ganglia following primary infection and reactivating through physical or emotional triggers. Clinical presentation manifests as grouped vesicles on erythematous bases progressing to painful ulceration and crusting, with manifestations ranging from oral-labial cold sores to genital lesions and potentially severe complications including herpetic keratoconjunctivitis and encephalitis requiring emergent intervention. Diagnostic confirmation relies primarily on viral culture obtained within the acute phase, supplemented by polymerase chain reaction or cytological examination, while management prioritizes symptom mitigation through antivirals such as acyclovir and valacyclovir, with suppressive therapy recommended for patients experiencing frequent recurrences to substantially reduce disease burden and transmission risk.