**Core Concept**
Reiter's syndrome, also known as reactive arthritis, is a type of spondyloarthritis that occurs in response to an infection, often gastrointestinal or urethral. This condition is characterized by a triad of symptoms: arthritis, conjunctivitis, and urethritis.

**Why the Correct Answer is Right**
Reiter's syndrome is a form of reactive arthritis, which is triggered by an immune response to an infection. The condition typically presents with a triad of symptoms, including arthritis, conjunctivitis (inflammation of the eyes), and urethritis (inflammation of the urethra). The exact mechanism of reactive arthritis is not fully understood, but it is thought to be related to the activation of the immune system in response to an infection.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because Reiter's syndrome is not typically characterized by fever and rash, although these symptoms can occur in some cases. However, the classic triad of symptoms includes arthritis, conjunctivitis, and urethritis.
* **Option B:** This option is incorrect because Reiter's syndrome is not typically characterized by the presence of anti-nuclear antibodies (ANA), which are associated with autoimmune diseases such as lupus.
* **Option C:** This option is incorrect because Reiter's syndrome is not typically characterized by the presence of a rash, although a rash can occur in some cases. The classic triad of symptoms includes arthritis, conjunctivitis, and urethritis.

**Clinical Pearl / High-Yield Fact**
Reiter's syndrome is often associated with the HLA-B27 genetic marker, which is also associated with other forms of spondyloarthritis.

**Correct Answer:** D.