Which sexually transmitted disease is highly infectious and causes blister-like lesions on the genitalia?

• A. Gonorrhea
• B. Human Papillomavirus Infection
• C. Syphilis
• D. Genital herpes

Answer: (D)

Blister-like genital lesions that are highly infectious point to genital herpes caused by herpes simplex virus. The hallmark is grouped vesicles on an inflamed base that rupture to form painful ulcers, and the infection is easily transmitted through intimate skin-to-skin contact. Transmission can occur even when there are no visible sores due to viral shedding. In contrast, gonorrhea typically causes urethral discharge and dysuria; HPV tends to cause warts or precancerous changes rather than vesicular lesions; and syphilis usually begins with a painless chancre rather than vesicles (though it can have other mucocutaneous findings later). So genital herpes best fits the description.