A 20 year old young female had history of recurrent acne on the face treated with many antibiotics like clindamycin, tetracycline, erythromycin and others. Now she complained of multiple hyperpigmented spots at the site of old acne lesions. Which of the following drug might have been responsible for this –

**Core Concept**
The question is testing the side effect profile of commonly used antibiotics in acne treatment, specifically their potential to cause hyperpigmentation.

**Why the Correct Answer is Right**
Hyperpigmentation in the context of acne treatment is often associated with the use of tetracyclines, particularly minocycline. Minocycline is a semi-synthetic derivative of tetracycline that has a broad spectrum of antimicrobial activity. It is known to cause a range of side effects, including skin hyperpigmentation, which can manifest as blue-gray or brown discoloration of the skin. This is thought to occur due to the deposition of iron and other metal ions in the skin, which can lead to the formation of melanin.

**Why Each Wrong Option is Incorrect**
**Option A:** Clindamycin is a lincosamide antibiotic that is commonly used to treat acne. While it can cause a range of side effects, including skin rashes and allergic reactions, it is not typically associated with hyperpigmentation.

**Option B:** Erythromycin is a macrolide antibiotic that is often used to treat mild to moderate acne. Like clindamycin, it can cause skin rashes and allergic reactions, but it is not commonly linked to hyperpigmentation.

**Option C:** This option is blank and requires a drug name.

**Clinical Pearl / High-Yield Fact**
Tetracyclines, including minocycline, can cause a range of side effects, including hyperpigmentation, blue-gray discoloration of the teeth (in children and adolescents), and photosensitivity. It is essential to carefully monitor patients taking these medications for any signs of adverse effects.

**Correct Answer:** C. Minocycline is a semi-synthetic derivative of tetracycline that has a broad spectrum of antimicrobial activity and is known to cause hyperpigmentation as a side effect.

✓ Correct Answer: C. Minocycline