Acne & isotretinoin flashcards
13 high-yield MRCP Part 1 cards from the Intellect Medicos Dermatology course. Try to answer each question before you open it — then study them properly with spaced repetition, which brings each card back just before you would forget it.
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What is the NICE first-line treatment for mild-to-moderate acne?
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A 12-week course of a fixed topical combination: adapalene + benzoyl peroxide, tretinoin + clindamycin, or benzoyl peroxide + clindamycin.
Why? Combinations target comedones and bacteria together; benzoyl peroxide also reduces antibiotic resistance.
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In moderate-to-severe acne, which oral antibiotics does NICE recommend adding to topical treatment?
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Lymecycline or doxycycline, combined with topical adapalene + benzoyl peroxide or topical azelaic acid, as a 12-week course.
Why? An oral tetracycline is added to topical therapy for inflammatory nodules and widespread disease; topical-only combinations are also first-line options in moderate-to-severe acne.
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What is the most common adverse effect of oral isotretinoin?
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Mucocutaneous dryness — especially cheilitis (dry, cracked lips), plus dry skin, dry eyes and nosebleeds.
Why? Isotretinoin shrinks sebaceous glands, so skin and mucosae dry out.
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Which tests are needed before starting oral isotretinoin?
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Pregnancy test (if able to become pregnant), liver function tests and fasting lipids; LFTs and lipids are repeated 1 month after starting, then every 3 months.
Why? Isotretinoin causes transaminitis and raised triglycerides, with a risk of pancreatitis if triglycerides are very high.
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Under the MHRA Pregnancy Prevention Programme, what contraception is required with isotretinoin?
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At least one highly effective method (e.g. IUD or implant) or two complementary methods (e.g. pill + condom), from 1 month before until 1 month after treatment.
Why? Isotretinoin is highly teratogenic (craniofacial, cardiac and CNS malformations).
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Which antibiotic class must not be co-prescribed with isotretinoin, and why?
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Tetracyclines (e.g. doxycycline, lymecycline) — combined risk of benign intracranial hypertension.
Why? Both can independently raise intracranial pressure, causing headache and visual disturbance.
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Which topical drug is used for persistent facial erythema in rosacea?
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Brimonidine gel — an alpha-2 adrenergic agonist that causes vasoconstriction.
Why? The effect lasts hours and rebound redness can occur. Advise daily high-factor sunscreen and avoiding triggers such as alcohol, spicy food and heat.
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What is the first-line topical treatment for mild-to-moderate papulopustular rosacea?
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Topical ivermectin cream.
Why? Alternatives are topical azelaic acid or metronidazole. For moderate-to-severe disease, oral doxycycline is added.
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Which hormonal treatment can be added for acne in women, and what is its main risk?
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Co-cyprindiol (ethinylestradiol + cyproterone acetate) — a higher risk of venous thromboembolism than levonorgestrel-containing combined pills.
Why? For acne with polyendocrine metabolic ovarian syndrome (PMOS, formerly PCOS), NICE suggests adding co-cyprindiol or another combined pill if first-line treatment fails, reviewing co-cyprindiol at 6 months.
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How does oral isotretinoin work in acne?
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It shrinks sebaceous glands and markedly reduces sebum production, and normalises follicular keratinisation.
Why? Less sebum also means fewer Cutibacterium acnes and less inflammation; acting on all the main drivers of acne is why it can produce long-lasting remission.
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Which psychiatric adverse effects must patients be warned about before starting isotretinoin?
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Depression, anxiety and mood changes, and rarely suicidal thoughts or behaviour.
Why? MHRA (2023) requires a mental health assessment before starting and at each review; patients and families should seek help promptly if mood worsens.
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How urgently should a patient with acne fulminans be referred?
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Same day to the on-call hospital dermatology team, to be assessed within 24 hours.
Why? Acne fulminans is a severe ulcerating, haemorrhagic acne with systemic upset (e.g. fever, arthralgia). Acne conglobata and nodulo-cystic acne also need referral to a consultant dermatologist-led team.
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Which topical acne drugs are contraindicated in pregnancy and when planning a pregnancy?
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Topical retinoids (e.g. adapalene, tretinoin).
Why? NICE NG198 states that topical retinoids and oral tetracyclines are contraindicated during and when planning pregnancy; oral isotretinoin is absolutely contraindicated.