Painless ulcer along with painless lymphadenopathy is characteristic of which STD –
**Core Concept**
The question is testing the student's knowledge of sexually transmitted diseases (STDs) and their clinical manifestations. The characteristic presentation of a painless ulcer along with painless lymphadenopathy is a key feature of certain STDs.
**Why the Correct Answer is Right**
The correct answer is **Syphilis**. The painless ulcer in syphilis is known as a chancre, which typically appears at the site of initial infection. The associated painless lymphadenopathy is a result of the body's immune response to the infection. Syphilis is caused by the bacterium Treponema pallidum, which enters the body through mucous membranes or small skin abrasions during sexual contact.
**Why Each Wrong Option is Incorrect**
**Option A:** Chancroid is caused by Haemophilus ducreyi and typically presents with painful ulcers and tender lymphadenopathy, making it an incorrect choice.
**Option B:** Herpes simplex virus (HSV) causes painful ulcers and can be accompanied by painful lymphadenopathy, so it's not the correct answer.
**Option C:** Donovanosis, also known as granuloma inguinale, is caused by Klebsiella granulomatis and typically presents with painless ulcers, but it is not commonly associated with painless lymphadenopathy.
**Clinical Pearl / High-Yield Fact**
To remember the key features of syphilis, use the mnemonic "CARES": Chancre, Adenopathy, Rash, Eschar, and Systemic symptoms.
**Correct Answer: C. Syphilis**