Regarding the mechanism of action of topical azelaic acid in acne and rosacea, which statement is CORRECT?

• A It acts by suppressing sebaceous gland secretion via androgen receptor blockade
• B It inhibits 5-alpha reductase and is effective only in hormonal acne
• C It works exclusively by competitively inhibiting dihydrofolate reductase in C. acnes
• D It has antimicrobial, anti-comedonal, and anti-inflammatory properties including inhibition of reactive oxygen species ✓

Explanation

Azelaic acid (a naturally occurring dicarboxylic acid) has multiple mechanisms: it is bacteriostatic against Cutibacterium acnes and Staphylococcus epidermidis, inhibits follicular keratinisation (anti-comedonal), and reduces reactive oxygen species (anti-inflammatory) — making it effective for both inflammatory acne and rosacea. Additionally, it inhibits tyrosinase, making it useful for post-inflammatory hyperpigmentation. It does NOT act via androgen receptor blockade or dihydrofolate reductase inhibition. Its multi-modal action makes it a safe option in pregnancy (Category B).

Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.