**Core Concept**
Jacuzzi syndrome, also known as hot tub folliculitis, is a skin infection caused by the bacterium *Pseudomonas aeruginosa*. This condition typically occurs in individuals who have recently used a hot tub or whirlpool bath that was contaminated with the bacteria.

**Why the Correct Answer is Right**
The correct answer, **Option B**, is correct because Jacuzzi syndrome is indeed also known as hot tub folliculitis. This condition is characterized by the development of itchy, painful follicular lesions on the skin, usually on the buttocks, thighs, or genital area, after exposure to contaminated water. The lesions are caused by the invasion of *Pseudomonas aeruginosa* into the hair follicles.

**Why Each Wrong Option is Incorrect**
**Option A:** Pneumococcus is a type of bacterium that causes pneumonia, not Jacuzzi syndrome. This option is incorrect because Pneumococcus is not associated with hot tub folliculitis.
**Option C:** Jacuzzi syndrome is not a progressive illness. While it can cause discomfort and itching, it is typically a self-limiting condition that resolves on its own within a few days.
**Option D:** Jacuzzi syndrome is not always a painless condition. In fact, the lesions associated with this condition can be quite painful, especially when scratched or irritated.

**Clinical Pearl / High-Yield Fact**
It's worth noting that Jacuzzi syndrome is often associated with the use of hot tubs or whirlpool baths that are not properly maintained or disinfected. To avoid this condition, it's essential to check the water temperature and chemical levels before using a hot tub, and to shower before and after use.

**✓ Correct Answer: B. It is also known as hot tub folliculitis.**