Dermatologist Certificate Dermatopharmacology and Topical Therapy 1 — Questions and Answers
Question 1: Which topical retinoid is considered the gold standard for treating photodamage and acne?
- Tretinoin (all-trans retinoic acid) (Correct answer)
- Adapalene
- Tazarotene
- Retinol
Correct answer: Tretinoin (all-trans retinoic acid)
Tretinoin is the prototypical topical retinoid with the strongest evidence base for treating acne, photodamage, and fine wrinkles by modulating keratinocyte differentiation and stimulating collagen.
Question 2: What is the vehicle that determines the potency classification of topical corticosteroids?
- The formulation (ointment > gel > cream > lotion > solution) significantly affects potency (Correct answer)
- Concentration alone determines potency
- Molecular weight of the steroid
- pH of the preparation
Correct answer: The formulation (ointment > gel > cream > lotion > solution) significantly affects potency
The same corticosteroid molecule can have different potency classes depending on the vehicle — ointments provide the greatest occlusion and skin penetration, followed by gels, creams, and lotions.
Question 3: Calcineurin inhibitors (tacrolimus and pimecrolimus) are used as steroid-sparing agents for which condition?
- Atopic dermatitis, especially on the face and intertriginous areas (Correct answer)
- Psoriasis plaques on the trunk
- Actinic keratoses
- Seborrheic dermatitis
Correct answer: Atopic dermatitis, especially on the face and intertriginous areas
Topical calcineurin inhibitors block T-cell activation and are indicated for atopic dermatitis, particularly as steroid-sparing agents for sensitive areas like the face and skin folds.
Question 4: What is the primary mechanism by which benzoyl peroxide treats acne?
- Releases free oxygen radicals that are bactericidal against Cutibacterium acnes (Correct answer)
- Inhibits 5-alpha reductase reducing sebum production
- Blocks androgen receptors in sebaceous glands
- Modulates toll-like receptor 2 signaling
Correct answer: Releases free oxygen radicals that are bactericidal against Cutibacterium acnes
Benzoyl peroxide is bactericidal against C. acnes through the release of reactive oxygen species, and critically, it does not induce antibiotic resistance.
Question 5: Which topical medication is first-line treatment for rosacea-associated papulopustular lesions?
- Metronidazole 0.75–1% gel or cream (Correct answer)
- Clindamycin 1% solution
- Erythromycin 2% gel
- Dapsone 5% gel
Correct answer: Metronidazole 0.75–1% gel or cream
Topical metronidazole is first-line therapy for inflammatory rosacea, reducing papules, pustules, and erythema through anti-inflammatory and antiparasitic (anti-Demodex) mechanisms.
Question 6: Salicylic acid functions as a keratolytic agent by what mechanism?
- Disrupts intercellular lipid bilayers causing desquamation of the stratum corneum (Correct answer)
- Inhibits prostaglandin synthesis reducing inflammation
- Chelates calcium ions disrupting desmosomes
- Activates proteases that cleave corneodesmosin
Correct answer: Disrupts intercellular lipid bilayers causing desquamation of the stratum corneum
Salicylic acid solubilizes the intercellular cement substance of the stratum corneum, reducing corneocyte cohesion and promoting shedding of hyperkeratotic scale.
Dermatologist Certificate Dermatopharmacology and Topical Therapy 1
Which topical retinoid is considered the gold standard for treating photodamage and acne?