Eczema and scabies: topical and systemic treatments MCQs With Answer

Eczema and scabies: topical and systemic treatments MCQs With Answer

This quiz set is designed for M.Pharm students studying Pharmacotherapeutics I (MPP 102T) to deepen understanding of evidence-based topical and systemic management of eczema and scabies. It covers pharmacology, mechanisms of action, potency classification, therapeutic indications, adverse effects, contraindications, and special-population considerations. Questions emphasize rational drug selection, comparative pharmacokinetics, resistance concerns for scabicides, and clinical application of emollients, corticosteroids, calcineurin inhibitors, antimicrobials and systemic agents like ivermectin and oral steroids. Use these MCQs to test clinical reasoning and prepare for exams by integrating pharmacotherapeutic principles with dermatological practice.

Q1. Which topical corticosteroid has the highest potency among the options listed and is commonly used for severe localized eczema unresponsive to mid-potency steroids?

• Hydrocortisone 1% cream
• Betamethasone dipropionate 0.05% ointment
• Clobetasol propionate 0.05% cream
• Triamcinolone acetonide 0.1% cream

Correct Answer: Clobetasol propionate 0.05% cream

Q2. Which mechanism best describes how topical calcineurin inhibitors (e.g., tacrolimus) reduce eczematous inflammation?

• Inhibition of phospholipase A2 reducing prostaglandin synthesis
• Blocking sodium channels in sensory neurons to reduce pruritus
• Inhibition of calcineurin-mediated dephosphorylation of NFAT, reducing T-cell cytokine transcription
• Stabilization of mast cell membranes to prevent histamine release

Correct Answer: Inhibition of calcineurin-mediated dephosphorylation of NFAT, reducing T-cell cytokine transcription

Q3. For widespread severe atopic eczema with extensive weeping lesions and risk of bacterial superinfection, what is the most appropriate next systemic intervention?

• Short course oral corticosteroids to control inflammation
• Immediate systemic antibiotic therapy without addressing inflammation
• Topical emollients alone and observation
• Topical antiseptic baths and avoid systemic drugs

Correct Answer: Short course oral corticosteroids to control inflammation

Q4. Which topical agent is contraindicated for long-term continuous use on thin skin areas (e.g., face, groin) due to higher risk of atrophy?

• Low-potency hydrocortisone 1% cream
• Calcineurin inhibitor ointment (tacrolimus 0.03%)
• High-potency clobetasol propionate 0.05% cream
• Emollient moisturizers with ceramides

Correct Answer: High-potency clobetasol propionate 0.05% cream

Q5. Which of the following is the recommended first-line topical scabicide for uncomplicated human scabies in adults?

• Benzyl benzoate 25% lotion single overnight application
• Permethrin 5% cream applied overnight and repeated after 7–14 days
• Oral ivermectin single dose only
• Topical sulfur ointment applied daily for 2 days

Correct Answer: Permethrin 5% cream applied overnight and repeated after 7–14 days

Q6. Which pharmacokinetic property of topical corticosteroids influences systemic absorption and risk of HPA-axis suppression?

• Lipophilicity, vehicle (ointment vs cream), skin integrity and occlusion
• Oral bioavailability and first-pass hepatic metabolism
• Renal clearance and protein binding
• Volume of distribution and half-life after IV administration

Correct Answer: Lipophilicity, vehicle (ointment vs cream), skin integrity and occlusion

Q7. Which adverse effect is most specifically associated with long-term topical calcineurin inhibitor use and prompted boxed warnings, though evidence remains debated?

• Increased risk of skin atrophy
• Potential increased risk of lymphoma and skin malignancy
• Hypertension and fluid retention
• Hypertrichosis at the application site

Correct Answer: Potential increased risk of lymphoma and skin malignancy

Q8. Which systemic agent is recommended for crusted (Norwegian) scabies or severe scabies in immunocompromised patients?

• Topical permethrin alone
• Oral ivermectin in repeated doses combined with topical permethrin
• Oral azithromycin single dose
• Topical benzoyl peroxide

Correct Answer: Oral ivermectin in repeated doses combined with topical permethrin

Q9. Which antibiotic is most appropriate for treating secondary bacterial infection (impetiginization) in eczema when Staphylococcus aureus is suspected and MRSA prevalence is low?

• Flucloxacillin (or dicloxacillin) oral therapy
• Oral vancomycin
• Topical mupirocin only for widespread systemic infection
• Oral ciprofloxacin as first-line

Correct Answer: Flucloxacillin (or dicloxacillin) oral therapy

Q10. What is the primary therapeutic benefit of regular emollient use in atopic eczema management?

• Direct anti-inflammatory activity comparable to steroids
• Restoration of epidermal barrier, reducing transepidermal water loss and flare frequency
• Eradication of scabies mites from the skin
• Antibacterial cleansing to prevent infection

Correct Answer: Restoration of epidermal barrier, reducing transepidermal water loss and flare frequency

Q11. Which of the following best describes the action of permethrin on Sarcoptes scabiei?

• Inhibition of parasitic DNA synthesis via folate antagonism
• Blocking gamma-aminobutyric acid (GABA)-gated chloride channels causing neuronal hyperexcitation and paralysis
• Competitive antagonism at nicotinic acetylcholine receptors leading to paralysis
• Disruption of chitin synthesis in mite exoskeleton

Correct Answer: Blocking gamma-aminobutyric acid (GABA)-gated chloride channels causing neuronal hyperexcitation and paralysis

Q12. Which systemic therapy is indicated for severe, refractory atopic dermatitis and acts by targeting IL-4 and IL-13 pathways?

• Oral methotrexate
• Dupilumab, a monoclonal antibody against IL-4Rα
• Azathioprine as calcineurin inhibitor
• Oral cyclosporine as IL-13 antagonist

Correct Answer: Dupilumab, a monoclonal antibody against IL-4Rα

Q13. Regarding pediatric use, which scabicide is generally preferred for infants under 2 months due to better safety data?

• Permethrin 5% cream is universally recommended for neonates
• Topical sulfur 5–10% ointment has historical use and safety in young infants
• Oral ivermectin is first-line for neonates
• Benzyl benzoate 25% lotion is safe for neonates without dilution

Correct Answer: Topical sulfur 5–10% ointment has historical use and safety in young infants

Q14. Which monitoring parameter is most important for a patient on long-term systemic corticosteroids for severe eczema?

• Serum creatinine monthly
• Blood glucose, blood pressure, bone mineral density and signs of adrenal suppression
• Serial complete blood counts to detect agranulocytosis
• Chest X-ray to monitor for pulmonary fibrosis

Correct Answer: Blood glucose, blood pressure, bone mineral density and signs of adrenal suppression

Q15. When educating patients about topical steroid potency, which advice is most appropriate to minimize adverse effects while ensuring efficacy?

• Apply high-potency steroid to face and intertriginous areas daily for prolonged periods
• Use the lowest effective potency for the shortest duration, avoid occlusion on thin skin and taper when discontinuing
• Combine topical steroid and calcineurin inhibitor simultaneously on the same area for enhanced effect
• Use steroid intermittently every other month regardless of disease control

Correct Answer: Use the lowest effective potency for the shortest duration, avoid occlusion on thin skin and taper when discontinuing

Q16. Which topical antimicrobial is recommended for localized secondary infection of eczema due to methicillin-resistant Staphylococcus aureus (MRSA)?

• Topical mupirocin ointment applied to localized lesions
• Topical neomycin cream universally for MRSA
• Oral amoxicillin without sensitivity testing
• Topical clotrimazole to cover bacterial infection

Correct Answer: Topical mupirocin ointment applied to localized lesions

Q17. Which factor contributes most to treatment failure in scabies control at a household level?

• Using permethrin 5% cream for two people in household
• Failure to treat close contacts simultaneously and re-exposure
• Applying cream at night and washing off in morning
• Using emollients during scabies treatment

Correct Answer: Failure to treat close contacts simultaneously and re-exposure

Q18. Which systemic immunosuppressant is sometimes used off-label for severe refractory atopic dermatitis and requires TPMT testing before initiation? (Hint: test for thiopurine methyltransferase activity)

• Ciclosporin, requiring TPMT testing
• Azathioprine, requiring TPMT testing due to risk of myelosuppression
• Mycophenolate mofetil, TPMT mandatory
• Methotrexate, TPMT required prior to therapy

Correct Answer: Azathioprine, requiring TPMT testing due to risk of myelosuppression

Q19. Which statement about post-scabetic itch and treatment response is correct?

• Itch resolves immediately after mite eradication; persistent itch indicates treatment failure
• Post-scabetic pruritus can persist for weeks despite successful eradication due to hypersensitivity and may require symptomatic topical steroids or antihistamines
• Persistent rash after treatment always indicates reinfection and requires repeated ivermectin only
• No symptomatic therapy is indicated for post-scabetic itch as it is self-resolving within 48 hours

Correct Answer: Post-scabetic pruritus can persist for weeks despite successful eradication due to hypersensitivity and may require symptomatic topical steroids or antihistamines

Q20. Which formulation choice typically increases penetration of topical corticosteroids into the epidermis, enhancing efficacy for lichenified chronic eczema?

• Hydrophilic creams decrease penetration compared to ointments
• Ointment vehicles increase penetration and are generally more potent than creams
• Lotions increase occlusion and penetration compared to ointments
• Alcohol-based gels always provide the least penetration for anti-inflammatory effect

Correct Answer: Ointment vehicles increase penetration and are generally more potent than creams

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