A 30-year-old man with history of multiple exposures presents with painful non indurated ulcer on the glans penis since 5 days. The undermined sloughed edges of margins were noted. The most probable diagnosis is?
**Core Concept**
The patient's presentation suggests a diagnosis of a sexually transmitted infection (STI) with a characteristic skin lesion. The undermined sloughed edges of the ulcer's margins are a key clinical finding that points towards a specific etiology.
**Why the Correct Answer is Right**
The patient's symptoms and clinical findings are consistent with primary syphilis, caused by the bacterium *Treponema pallidum*. The painless nature of the ulcer is a classic characteristic of primary syphilis, which typically presents with a solitary, firm, painless chancre at the site of inoculation. However, in this case, the presence of pain and undermined sloughed edges suggests an alternative diagnosis. The undermined sloughed edges are more characteristic of chancroid, a STI caused by *Haemophilus ducreyi*.
**Why Each Wrong Option is Incorrect**
* **Option A:** Syphilis is typically painless, and the undermined sloughed edges are not a characteristic feature of primary syphilis.
* **Option B:** Herpes simplex virus (HSV) typically presents with multiple painful vesicles or ulcers, not a single ulcer with undermined sloughed edges.
* **Option C:** Granuloma inguinale, caused by *Klebsiella granulomatis*, typically presents with painless, beefy-red ulcers with well-defined borders, not undermined sloughed edges.
**Clinical Pearl / High-Yield Fact**
The presence of pain and undermined sloughed edges in a genital ulcer should raise suspicion for chancroid, a STI that requires prompt treatment to prevent complications.
**Correct Answer:** C.