Aesthetic Dermatology MCQ - Salicylic acid peel

A 32-year-old woman with mild acne and post-inflammatory hyperpigmentation seeks a chemical peel that will improve pigmentation, control sebaceous activity, and has additional antimicrobial properties. Which of the following peeling agents is BEST classified as having a metabolic action in addition to keratolysis?

A. Glycolic acid
B. Trichloroacetic acid
C. Salicylic acid
D. Resorcinol
E. Jessner’s solution

Correct Answer:
C. Salicylic acid

Explanation:
Chemical peeling agents can be classified by depth (superficial, medium, deep) and by mechanism of action: keratolytic, caustic, or metabolic.

• Salicylic acid is a β-hydroxy acid that has a metabolic action — meaning it penetrates sebaceous follicles, reduces sebum production, and has intrinsic anti-inflammatory and antimicrobial effects.

• Its lipophilicity makes it particularly effective in acne and post-inflammatory hyperpigmentation in darker skin types.

Other options:

• A. Glycolic acid: Alpha-hydroxy acid — works primarily by keratolysis and epidermolysis (superficial peel).

• B. Trichloroacetic acid: Caustic agent that causes protein coagulation and necrosis, used for medium-depth peels.

• D. Resorcinol: Keratolytic agent — component of Jessner’s solution, but not primarily metabolic.

• E. Jessner’s solution: Combination peel (resorcinol, salicylic acid, lactic acid, ethanol) with synergistic keratolytic effect — but salicylic acid is the agent with true metabolic action.

Key Point:
Salicylic acid is the prototype peel with metabolic action, offering sebostatic, comedolytic, and antimicrobial effects, making it ideal for acne-prone, oily skin.