**Question:** About nasal syphilis the following is true:

A. Syphilis primarily affects the skin and mucous membranes.
B. Syphilis causes inflammation of the nose and nasal passages.
C. Syphilis is a rare cause of nasal symptoms.
D. Syphilis is typically associated with late-stage cardiovascular complications.

**Core Concept:** Syphilis is a sexually transmitted infection caused by the bacterium Treponema pallidum. It can affect various organs and systems, including the skin, mucous membranes, cardiovascular system, and central nervous system.

**Why the Correct Answer is Right:** Syphilis can indeed affect the skin and mucous membranes, which is why option B is correct. In the early stage, it presents as chancre (primary syphilis), which is a painless ulcer on the skin, followed by secondary syphilis involving mucous membranes, including the nasal mucosa.

**Why Each Wrong Option is Incorrect:**

A. While syphilis can affect the skin and mucous membranes, it is not primarily a skin disease. Nasal syphilis is a manifestation of the infection, not a focus of the disease itself.

C. Nasal syphilis is a common presentation of early syphilis, not rare. The infection can affect the nasal mucosa, causing inflammation and symptoms like nasal discharge, congestion, and nasal obstruction.

D. Syphilis can lead to late-stage complications, such as cardiovascular involvement (e.g., aortic aneurysm, heart valve damage, and peripheral artery disease). However, this option misrepresents the primary focus of the question, which is nasal syphilis, not cardiovascular involvement.

**Clinical Pearl:** Nasal syphilis presents with symptoms like nasal congestion, discharge, and obstruction, making it crucial for physicians to consider syphilis in the differential diagnosis of a patient with unexplained nasal symptoms, especially if the patient has a history of sexually transmitted infections. A high index of suspicion and appropriate laboratory tests (e.g., Venereal Disease Research Laboratory test or serological tests) can lead to early diagnosis and treatment, preventing complications like cardiovascular involvement.