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MRCP PART 1 · DERMATOLOGY

Dermatology questions
for MRCP Part 1.

Clinora has 203 dermatology single best answer questions covering 197 topics. Every question explains all five options, separates the key clue from what it means and what to do next, and links to its source. Try the 5 sample questions below, then practise more for free.

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FREE SAMPLE QUESTIONS

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Question 1Bacterial/viral/fungal diseaseEasy

A 30-year-old man has a well-demarcated, spreading area of erythema, warmth, swelling and tenderness on his lower leg, with fever. There is no obvious abscess or fluctuance. What is the most likely diagnosis and first-line treatment?

  1. ACellulitis; oral or intravenous antibiotics depending on severity, guided by a validated severity classification
  2. BContact dermatitis; topical corticosteroid only
  3. CTinea corporis; topical antifungal only
  4. DVenous eczema; emollients only
  5. ESimple insect bite reaction; no treatment needed
Show answer and explanation

Answer: A Cellulitis; oral or intravenous antibiotics depending on severity, guided by a validated severity classification

Acute, spreading, warm, tender erythema of one lower leg with fever is cellulitis: bacterial infection of the dermis and subcutaneous tissue, usually caused by Streptococcus pyogenes or Staphylococcus aureus. Erysipelas is a more superficial form with a sharply raised edge. Look for an entry point such as a fissure between the toes, tinea pedis or a wound, and mark the edge so that spread can be judged. Grade severity, for example with the Eron classification. Class I (no systemic features) can usually be treated with oral antibiotics at home. Class III–IV, or rapid progression, needs IV antibiotics and admission. NICE NG141 recommends flucloxacillin first line; clarithromycin, erythromycin (in pregnancy) or doxycycline are alternatives in penicillin allergy. Treat for 5–7 days and review if it is not improving. Red flags for necrotising fasciitis are pain out of proportion to the skin findings, crepitus, rapid spread and systemic toxicity, and these need urgent surgery. Red, bilateral legs are rarely cellulitis; think of venous eczema or lipodermatosclerosis.

Key clue
Spreading tender erythema with fever, no fluctuant collection
What it means
Cellulitis
What to do
Start antibiotics appropriate to severity (oral for milder cases, intravenous for more severe/systemic illness), mark the margin to monitor progression, and consider admission if severity criteria are met

Why the other options are less appropriate

  • B Contact dermatitis is itchy rather than tender, has the shape of the exposure, and does not cause fever.
  • C Tinea corporis is a scaly annular rash without fever. Tinea pedis, though, can be the entry point for cellulitis.
  • D Venous eczema is chronic, usually affects both legs, and causes itch and scaling rather than an acute febrile illness.
  • E An insect bite reaction does not explain fever with spreading tender erythema. This needs antibiotics.

Source: NICE NG141 Cellulitis and erysipelas: antimicrobial prescribing

Question 2Limited plaque psoriasis — initial topical treatmentEasy

A 34-year-old woman has well-demarcated scaly plaques covering 3% of her trunk and limbs. Her scalp, face, flexures and nails are unaffected, and there are no joint symptoms. Which initial prescription is most appropriate?

  1. AA potent topical corticosteroid once daily plus a vitamin D analogue once daily
  2. BA mild topical corticosteroid alone for eight weeks
  3. COral methotrexate with folic acid from the outset
  4. DNarrowband ultraviolet B phototherapy as first treatment
  5. EA topical calcineurin inhibitor twice daily
Show answer and explanation

Answer: A A potent topical corticosteroid once daily plus a vitamin D analogue once daily

Limited plaque psoriasis on the trunk and limbs, with no involvement of the scalp, face, flexures, nails or joints, is treated topically first. NICE CG153 recommends a potent corticosteroid once daily plus a vitamin D or vitamin D analogue once daily, applied separately (one in the morning, one in the evening), for up to 4 weeks. Review adults 4 weeks after starting. If this fails, the next step is a vitamin D preparation twice daily. If that also fails after 8 to 12 weeks, use either a potent corticosteroid twice daily for up to 4 weeks or a coal tar preparation. A combined calcipotriol and betamethasone product once daily is another option. NICE advises against continuous potent corticosteroid use at any one site for more than 8 weeks, and against very potent agents for more than 4 weeks, with a 4-week break between courses. Phototherapy and systemic therapy are for disease that cannot be controlled topically, is extensive, or has a major impact. Ask about joint symptoms at each review, because psoriatic arthritis is common, and screen for it with a tool such as PEST.

Key clue
Limited plaque psoriasis confined to the trunk and limbs
What it means
Adult trunk or limb plaques should begin with the NICE site-specific topical combination
What to do
A potent topical corticosteroid once daily plus a vitamin D analogue once daily

Why the other options are less appropriate

  • B Mild corticosteroids are kept for the face, flexures and genitals. On the thick plaques of the trunk and limbs they are usually not effective enough.
  • C Methotrexate is for extensive or high-impact psoriasis that topical treatment cannot control. It is not used first for 3% involvement.
  • D Narrowband UVB is offered when topical treatment fails or disease is extensive. It is not the first step for limited plaques.
  • E Calcineurin inhibitors are used off-label on the face, flexures and genitals when steroids are unsuitable, not first line on trunk plaques.

Source: NICE CG153: Psoriasis — topical treatment of trunk and limb psoriasis

Question 3Psoriasis with inflammatory joint symptomsMedium

At an annual review, a 42-year-old woman with psoriasis reports six months of swollen fingers and morning stiffness lasting 90 minutes. What is the most appropriate action?

  1. AReassure because skin severity does not predict arthritis
  2. BOrder rheumatoid factor and defer action until the result
  3. CIncrease topical corticosteroid treatment for three months
  4. DUse a validated psoriatic arthritis tool and refer promptly to rheumatology
  5. ERequest a plain radiograph and review routinely in one year
Show answer and explanation

Answer: D Use a validated psoriatic arthritis tool and refer promptly to rheumatology

Dactylitis (swollen fingers) and morning stiffness of 90 minutes in someone with psoriasis strongly suggest inflammatory arthritis, most likely psoriatic arthritis. Up to about a third of people with psoriasis develop it, and in most the skin disease comes first. Joint disease does not track skin severity, and nail, scalp and flexural psoriasis carry a higher risk. NICE CG153 recommends assessing people with psoriasis for psoriatic arthritis at least once a year, especially in the first 10 years, using a validated tool such as the Psoriasis Epidemiology Screening Tool (PEST). A PEST score of 3 or more suggests referral, but PEST does not detect axial disease or inflammatory back pain. When psoriatic arthritis is suspected, refer to rheumatology promptly; NICE NG100 asks that suspected persistent synovitis is seen within 3 weeks of referral. Early disease-modifying treatment limits joint damage and disability. Rheumatoid factor is usually negative and early radiographs are often normal, so neither should delay referral.

Key clue
Psoriasis with prolonged morning stiffness and swollen digits
What it means
Annual assessment has uncovered probable inflammatory psoriatic arthritis requiring early specialist diagnosis
What to do
Use a validated psoriatic arthritis tool and refer promptly to rheumatology

Why the other options are less appropriate

  • A Skin severity does not predict arthritis, but dactylitis and prolonged morning stiffness are inflammatory features that need assessment.
  • B Psoriatic arthritis is usually seronegative, so a negative rheumatoid factor would not exclude it. Testing should not delay referral.
  • C Topical steroids treat skin plaques only. They do nothing for joint inflammation and would delay treatment that prevents damage.
  • E Early radiographs are often normal. Waiting a year risks irreversible joint damage that early treatment could prevent.

Source: NICE CG153: Psoriasis — assessment and referral for psoriatic arthritis

Question 4Atopic eczema flare — core topical treatmentMedium

A 24-year-old woman with atopic eczema has dry skin generally and an itchy inflammatory flare on her limbs. There is no weeping, crusting or fever. Which management principle is most appropriate?

  1. AStop emollients while any topical corticosteroid is being used
  2. BContinue regular emollient and use a site- and severity-matched topical corticosteroid on active eczema
  3. CGive oral flucloxacillin because scratching implies bacterial infection
  4. DUse the strongest available topical corticosteroid over every site
  5. EAvoid topical anti-inflammatory treatment until allergy testing is complete
Show answer and explanation

Answer: B Continue regular emollient and use a site- and severity-matched topical corticosteroid on active eczema

Generally dry skin with an itchy, inflamed flare and no weeping, crusting or fever points to an uninfected flare of atopic eczema. Two problems need treatment at once: the skin barrier and the inflammation. Emollients repair the barrier and should be used liberally and often, including when the skin is clear. Adults commonly need around 500 g a week. Active areas are treated with a topical corticosteroid matched to the site and severity. For a limb flare in an adult, a moderate steroid such as clobetasone butyrate 0.05% or a potent one such as betamethasone valerate 0.1% or mometasone 0.1% is used. Use mild steroids, such as hydrocortisone 1%, on the face and flexures, and very potent steroids only with specialist advice. Apply once or twice daily, measured in fingertip units (one unit, about 0.5 g, covers an area the size of two adult palms), and continue until about 48 hours after the flare settles. Weeping, crusting or fever would suggest infection, and painful punched-out erosions suggest eczema herpeticum, which needs aciclovir the same day.

Key clue
Uncomplicated inflammatory atopic eczema flare with background xerosis
What it means
Barrier maintenance remains necessary while active inflammation needs appropriately potent topical treatment
What to do
Continue regular emollient and use a site- and severity-matched topical corticosteroid on active eczema

Why the other options are less appropriate

  • A Emollients are the foundation of eczema care and should continue alongside topical steroids, spaced apart in time.
  • C Scratching alone does not mean infection. There is no weeping, crusting or fever, so antibiotics are not indicated.
  • D Very potent steroids on every site, including the face and flexures, risk atrophy and other side effects. Potency should be matched to site.
  • E Allergy testing is not routinely needed and should not delay standard treatment of a flare.

Source: Primary Care Dermatology Society: Atopic eczema — topical management

Question 5Isotretinoin — emerging mental or sexual-function concernHard

Six weeks after starting isotretinoin, a 21-year-old man reports marked low mood and new sexual dysfunction. He denies immediate self-harm intent but is distressed. What is the most appropriate response?

  1. AReassure that neither symptom needs monitoring during isotretinoin treatment
  2. BDouble the isotretinoin dose to shorten total exposure
  3. CArrange prompt assessment of both concerns, assess risk and use shared decision-making about treatment
  4. DWait until the routine end-of-course appointment without documenting symptoms
  5. EAttribute both symptoms to acne without considering treatment association
Show answer and explanation

Answer: C Arrange prompt assessment of both concerns, assess risk and use shared decision-making about treatment

New low mood and sexual dysfunction 6 weeks into isotretinoin need prompt, documented assessment, not reassurance or delay. Both are recognised possible adverse effects. After its review, the MHRA introduced additional measures: assessment of mental health and sexual function before treatment, discussion of these risks with the patient, and monitoring of both throughout treatment. Ask about mood, anxiety, sleep, suicidal thoughts and self-harm, and assess risk in a structured way. Ask specifically about erectile dysfunction and reduced libido. Decisions about continuing, reducing or stopping isotretinoin should be shared with him and made with the specialist prescriber. If serious psychiatric symptoms are present, stopping isotretinoin should be considered and urgent mental health input sought. Mood symptoms may not settle straight away after stopping, so follow-up should continue, and he should know where to get urgent help. For patients under 18, the MHRA requires two prescribers to agree that treatment is appropriate.

Key clue
New substantial mood and sexual-function symptoms after starting isotretinoin
What it means
Current safety measures require active monitoring, prompt risk assessment and individualised treatment review
What to do
Arrange prompt assessment of both concerns, assess risk and use shared decision-making about treatment

Why the other options are less appropriate

  • A Mental health and sexual function are both part of current MHRA monitoring. New symptoms need assessment, not reassurance.
  • B Increasing the dose could worsen adverse effects and ignores the harm he is reporting. It is not a safe response.
  • D Waiting for the end-of-course review without recording symptoms delays care and conflicts with the requirement for ongoing monitoring.
  • E These symptoms began on treatment and are recognised possible effects. Blaming acne alone without assessment is unsafe.

Source: MHRA: Isotretinoin — changes to prescribing guidance and additional risk minimisation measures

That is 5 of 203. Carry on with dermatology in the practice bank, with progress tracking, flashcards and timed sessions.

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Topics covered

Show all 197 dermatology topics
  • A negative PEST does not exclude axial disease
  • A topical antibiotic is not enough
  • Acanthosis nigricans
  • Acne treatment safety
  • Acne vulgaris
  • Acquired ichthyosis red flag
  • Acquired reactive perforating collagenosis
  • Acrodermatitis enteropathica
  • Actinic keratosis
  • Actinic keratosis on a poor-healing site
  • Acute mast-cell activation
  • Acute paronychia
  • Adherent scale limiting scalp treatment
  • Adjunctive topicals during systemic psoriasis treatment
  • Advanced basal cell carcinoma
  • AGEP
  • Allergic contact dermatitis patch testing
  • Alopecia areata
  • Anaphylaxis
  • Antihistamine-refractory chronic urticaria
  • Antimicrobial duration in acne
  • Ashy dermatosis
  • Atopic eczema flare
  • Atopic eczema infection
  • Autoimmune blistering
  • Bacterial/viral/fungal disease
  • Basal cell carcinoma morphology
  • Bazex syndrome
  • Bowel-associated dermatosis–arthritis syndrome
  • Breaks between potent topical steroid courses
  • Bullous disease
  • Bullous pemphigoid
  • Bullous pemphigoid: efficacy–safety trade-off
  • Calculating PASI response
  • Cellulitis differential
  • Chronic leg ulcer biopsy indication
  • Chronic plaque psoriasis
  • Chronic plaque psoriasis systemic association
  • Chronic spontaneous urticaria
  • Classical scabies
  • Cold urticaria
  • Continuous very potent steroid exposure
  • Crusted scabies
  • Cutaneous anthrax eschar
  • Cutaneous larva migrans
  • Cutaneous melanoma nodal assessment
  • Cutaneous mucormycosis warning
  • Cutaneous polyarteritis nodosa
  • Cutaneous SCC
  • Cutaneous small-vessel vasculitis
  • Cutaneous squamous-cell carcinoma
  • Cutaneous vasculitis
  • Darier disease
  • Delusional infestation
  • Dermatitis artefacta
  • Dermatitis herpetiformis
  • Dermatomyositis cutaneous clues
  • Dermatomyositis malignancy assessment
  • Dermatophyte onychomycosis
  • Disseminated cutaneous lupus
  • DRESS
  • DRESS syndrome
  • DRESS with cardiac involvement
  • Drug eruption
  • Ecthyma gangrenosum significance
  • Eczema herpeticum
  • Eosinophilic cellulitis differential
  • Epidermolysis bullosa acquisita
  • Eruptive xanthomas
  • Erysipelas morphology
  • Erythema ab igne cause
  • Erythema elevatum diutinum
  • Erythema multiforme
  • Erythema multiforme versus SJS
  • Erythema nodosum
  • Erythema persists after antibiotics
  • Erythrasma
  • Erythropoietic protoporphyria
  • Escalating acne with scarring risk
  • Facial and flexural psoriasis
  • Facial vitiligo
  • First review of an adult topical psoriasis treatment
  • Fixed drug eruption clue
  • Formulation-related apparent treatment failure
  • Generalised pustular psoriasis
  • Granuloma annulare recognition
  • Hailey-Hailey disease
  • Hidradenitis suppurativa
  • High-impact psoriasis uncontrolled by topical therapy
  • High-risk recurrent facial basal cell carcinoma
  • Hydroa vacciniforme
  • Irritant contact dermatitis mechanism
  • Isotretinoin
  • IV today, oral tomorrow?
  • Joint disease in systemic psoriasis treatment selection
  • Kaposi sarcoma
  • Kaposi sarcoma lesion
  • Leprosy
  • Leprosy neurological sign
  • Lichen planus
  • Lichen planus morphology
  • Lichen sclerosus
  • Lichen simplex chronicus
  • Limited alopecia areata
  • Limited plaque psoriasis
  • Linear IgA bullous disease
  • Livedo reticularis with renal disease
  • Livedoid vasculopathy
  • Localised cutaneous lupus
  • Localised non-bullous impetigo
  • Long-term surveillance after extensive PUVA
  • Loose anagen syndrome
  • Low-risk basal cell carcinoma
  • Lupus pernio association
  • Male genital lichen sclerosus
  • Measuring nail psoriasis severity
  • Melanoma assessment
  • Minocycline hyperpigmentation
  • Moderate-to-severe acne
  • Molluscum contagiosum
  • Morbilliform drug eruption
  • More pain than the redness suggests
  • Mucous membrane pemphigoid
  • Muir–Torre syndrome
  • Mycosis fungoides
  • Necrobiosis lipoidica
  • Necrobiotic xanthogranuloma
  • Necrolytic migratory erythema
  • Necrotising infection
  • Neutrophilic eccrine hidradenitis
  • Nodulocystic acne
  • Occupational hand dermatitis
  • Orf
  • Painful skin necrosis on haemodialysis
  • Palmar hyperhidrosis
  • Papular-purpuric gloves and socks syndrome
  • Papulopustular rosacea
  • Pellagra
  • Pemphigoid gestationis
  • Pemphigus vulgaris
  • Persistent moderate hidradenitis
  • Phototherapy after topical failure
  • Phototoxic drug eruption
  • Pityriasis rosea
  • Pityriasis rubra pilaris
  • Polymorphic light eruption
  • Porphyria cutanea tarda
  • Possible secondary bacterial infection of eczema
  • Preserving cumulative phototherapy information
  • Pressure ulcer prevention
  • Primary focal hyperhidrosis
  • Prurigo nodularis itch-scratch cycle
  • Pseudoporphyria drug association
  • Pseudoxanthoma elasticum
  • Psoriasis and arthritis
  • Psoriasis assessment in darker skin
  • Psoriasis with inflammatory joint symptoms
  • PUVA with a genetic skin-cancer predisposition
  • Pyoderma gangrenosum
  • Rapid conventional systemic psoriasis control
  • Rapid relapse after narrowband UVB
  • Rapidly progressive alopecia areata
  • Recurrent cellulitis and the preventive threshold
  • Resistant flexural psoriasis and steroid toxicity risk
  • Review at 12 weeks, not indefinitely
  • Rosacea with painful photophobic red eye
  • Routine maintenance phototherapy
  • SAPHO syndrome recognition
  • Scabies
  • Scarring alopecia
  • Seborrhoeic dermatitis
  • Secondary failure of targeted psoriasis treatment
  • Sézary syndrome
  • SJS/TEN
  • Solar urticaria timing
  • Squamous cell carcinoma risk
  • Stage IA melanoma
  • Stevens-Johnson ophthalmic involvement
  • Subcorneal pustular dermatosis
  • Suspected onychomycosis
  • Sweet syndrome
  • Systemic choice is individualised
  • Telogen effluvium
  • The skin score misses distress
  • The wrong organism after freshwater exposure
  • Thin melanoma
  • Tinea capitis
  • Tinea capitis management
  • Tinea corporis
  • Toenail onychomycosis
  • Unstable generalised psoriasis
  • Urticaria
  • Urticaria with airway symptoms
  • Venous leg ulcer
  • Vitiligo
  • Vulval lichen sclerosus
  • Who initiates a targeted treatment?

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