Herpes simplex labialis is caused by which pathogen and commonly presents as what?

Herpes simplex labialis is caused by which pathogen and commonly presents as what?

• A. Virus – cold sore / fever blister around the lips
• B. Bacteria – cold sore around the lips
• C. Fungi – cold sore around the lips
• D. Protozoa – cold sore around the lips

Answer: (A)

The key idea is that this lesion is caused by a virus, specifically herpes simplex virus, most often HSV-1. It characteristically appears as a painful cluster of vesicles on an erythematous area around the lips that crusts over—the familiar cold sore or fever blister. The virus remains latent in the trigeminal ganglion and can reactivate, producing recurrent episodes, especially with triggers like sun exposure, stress, or illness. This is not caused by bacteria, fungi, or protozoa, which is why the viral description with a cold sore around the lips is the correct characterization.

The key idea is that this lesion is caused by a virus, specifically herpes simplex virus, most often HSV-1. It characteristically appears as a painful cluster of vesicles on an erythematous area around the lips that crusts over—the familiar cold sore or fever blister. The virus remains latent in the trigeminal ganglion and can reactivate, producing recurrent episodes, especially with triggers like sun exposure, stress, or illness. This is not caused by bacteria, fungi, or protozoa, which is why the viral description with a cold sore around the lips is the correct characterization.