A patient may attend with a 'cold sore' lesion on their lip. Which one of the following statements about a cold sore lesion is true?

A cold sore, also known as a fever blister, is primarily caused by the herpes simplex virus (HSV), typically HSV type 1. This virus is known to have a close association with the trigeminal nerve, which innervates the facial region, including the lips. When the virus reactivates, often due to stress, illness, or immunosuppression, the lesions typically manifest around the lips or mouth due to the trigeminal nerve providing sensory innervation to this area.

Understanding this relationship with the trigeminal nerve helps explain why patients may experience recurrent outbreaks in the same location on their lips. The presence of the virus in the nerve cells means it can reactivate, leading to the formation of cold sores.

The other statements do not accurately reflect the nature of cold sore lesions. While the cold sore is indeed caused by a herpes virus, it is not the varicella virus (associated with chickenpox); rather, it is the herpes simplex virus. Cold sores are infectious during the outbreak and can be transmitted to others, contradicting the statement that they are not infectious. Additionally, cold sores are not considered premalignant lesions; rather, they are benign manifestations of viral infection. Understanding these aspects provides clarity