A female has a hypopigmented lesion on the centre of the forehead. Drug responsible is?
**Core Concept**
The question is testing knowledge of drug-induced skin depigmentation, specifically hypopigmentation. This is a condition characterized by the loss of melanin pigmentation in the skin, often caused by certain medications.
**Why the Correct Answer is Right**
The correct answer is a medication that selectively inhibits tyrosinase, an enzyme crucial for melanin production. When tyrosinase is inhibited, melanin synthesis is blocked, leading to hypopigmentation. This medication is commonly used in the treatment of hyperpigmentation disorders, such as melasma and post-inflammatory hyperpigmentation (PIH).
**Why Each Wrong Option is Incorrect**
**Option A:** This is a medication used to treat acne, and it's not associated with hypopigmentation. It works by reducing sebum production, but it doesn't affect melanin synthesis.
**Option B:** This is an antihistamine used to treat allergic reactions, and it's not known to cause hypopigmentation. It works by blocking histamine receptors, but it doesn't affect melanin production.
**Option C:** This is a medication used to treat hypertension, and it's not associated with hypopigmentation. It works by blocking alpha-1 adrenergic receptors, but it doesn't affect melanin synthesis.
**Clinical Pearl / High-Yield Fact**
Be aware that various medications can cause skin depigmentation, including hypopigmentation, as a side effect. Some common culprits include certain antibiotics, antimalarial medications, and psychiatric medications.
**Correct Answer:** D. Hydroquinone