**Core Concept**
Scrum pox, also known as herpes simplex virus (HSV) infection, is a dermatological condition that affects individuals involved in close-contact sports, such as rugby. It is characterized by the appearance of vesicular lesions on the skin, often accompanied by fever and malaise.

**Why the Correct Answer is Right**
The correct answer, **Option B: Caused by varicella zoster virus**, is incorrect because Scrum pox is actually caused by the herpes simplex virus (HSV), not varicella zoster virus. HSV is a highly contagious virus that spreads through skin-to-skin contact, and it is a common cause of skin infections in individuals who participate in close-contact sports.

**Why Each Wrong Option is Incorrect**
**Option A:** Scrum pox is indeed common in rugby players, as well as other athletes who engage in close-contact sports, making this statement true.
**Option C:** Acyclovir is a correct treatment for Scrum pox, as it is an antiviral medication that can help alleviate symptoms and shorten the duration of the infection.
**Option D:** Vesicular lesions and fever are indeed characteristic symptoms of Scrum pox, making this statement true.

**Clinical Pearl / High-Yield Fact**
It's essential for athletes and healthcare providers to recognize the signs and symptoms of Scrum pox, as prompt treatment can help prevent the spread of the infection and reduce the risk of complications.

**✓ Correct Answer: B. Caused by varicella zoster virus**