Free Specialty Certificate Examination in Dermatology Practice Questions

Sample Practice Questions

Try these 10 sample questions from the Specialty Certificate Examination in Dermatology practice bank. Each includes the answer and explanation. Continue with the interactive practice above to review the full question set.

1. 1A florist has recurrent delayed hand eczema after glove use. Which investigation is best suited to confirming the responsible contact allergen?

   1. A.Skin prick testing
   2. B.Closed patch testingCorrect answer: B
   3. C.Serum total IgE
   4. D.Intradermal testing

   Explanation: DermNet states: "Patch testing is undertaken for the investigation and confirmation of substances that produce allergic contact dermatitis." Delayed contact eczema calls for patch testing. Prick/intradermal tests assess immediate sensitisation; total IgE does not identify the delayed contact allergen.

   Reference: DermNet: Patch tests — What are patch tests?

2. 2Dermoscopy of a pigmented facial papule shows blue-grey nests, branching telangiectasia and focal ulceration without a pigment network. Which tumour is most likely?

   1. A.Malignant melanoma
   2. B.Basal cell carcinomaCorrect answer: B
   3. C.Squamous carcinoma in situ
   4. D.Seborrhoeic keratosis

   Explanation: DermNet states: "Linear and arborising (branch-like) telangiectasia" The combination of arborising vessels, absent network, nests and ulceration favours basal cell carcinoma.

   Reference: DermNet: Dermoscopy of basal cell carcinoma — Pigmented basal cell carcinoma

3. 3A dry sloughy ulcer needs donated moisture rather than high fluid absorption. Which dressing class primarily releases water to rehydrate the wound bed?

   1. A.Alginate dressing
   2. B.Hydrogel dressingCorrect answer: B
   3. C.Polyurethane foam
   4. D.Hydrofibre dressing

   Explanation: DermNet states: "Water is released to keep the wound moist" Hydrogels donate water; the other classes primarily absorb exudate.

   Reference: DermNet: Synthetic wound dressings — Hydrogels

4. 4A young adult develops numerous small drop-like scaly plaques after a streptococcal sore throat. Which psoriasis pattern best fits?

   1. A.Chronic plaque psoriasis
   2. B.Guttate psoriasisCorrect answer: B
   3. C.Flexural psoriasis
   4. D.Erythrodermic psoriasis

   Explanation: DermNet states: "Post-streptococcal acute guttate psoriasis" The acute post-streptococcal drop-like eruption identifies guttate psoriasis.

   Reference: DermNet: Psoriasis — Guttate psoriasis

5. 5White crinkled vulval plaques with scarring are diagnosed as lichen sclerosus. Which drug is an example of the ultrapotent topical steroid commonly used?

   1. A.Hydrocortisone 1%
   2. B.Clobetasol propionate 0.05%Correct answer: B
   3. C.Clobetasone butyrate 0.05%
   4. D.Betamethasone valerate 0.025%

   Explanation: DermNet states: "An ultrapotent topical steroid is often prescribed (eg, clobetasol propionate 0.05%)." The other listed formulations are less potent and do not answer the ultrapotent-agent question.

   Reference: DermNet: Lichen sclerosus — Topical steroid ointment

6. 6A child has multiple café-au-lait macules and characteristic axillary freckling. Which diagnosis should be considered?

   1. A.Tuberous sclerosis
   2. B.Neurofibromatosis type 1Correct answer: B
   3. C.Sturge–Weber syndrome
   4. D.Incontinentia pigmenti

   Explanation: DermNet states: "Freckling in the armpits, known as Crowe sign, is characteristic of neurofibromatosis type 1." Crowe sign in this context points to NF1.

   Reference: DermNet: Neurofibromatosis — Axillary freckling

7. 7A patient develops a recurrent itchy papular eruption hours after the first strong spring sunlight, lasting several days. Which diagnosis fits this timing?

   1. A.Solar urticaria
   2. B.Polymorphic light eruptionCorrect answer: B
   3. C.Phototoxic sunburn
   4. D.Porphyria cutanea tarda

   Explanation: DermNet states: "Onset: occurs within several hours to 1–2 days after exposure to sunlight and is usually intermittent." The seasonal delayed pruritic eruption fits PMLE, contrasting with immediate wealing or chronic skin fragility.

   Reference: DermNet: Polymorphic light eruption — Clinical features

8. 8A patient with extensive superficial skin loss has increased transepidermal water loss. Which layer normally provides the principal physical barrier?

   1. A.Papillary dermis
   2. B.Reticular dermis
   3. C.EpidermisCorrect answer: C
   4. D.Subcutis

   Explanation: DermNet states: "It acts as a physical barrier, preventing loss of water from the body" The epidermal barrier limits transepidermal water loss.

   Reference: DermNet: The structure of normal skin — A. Epidermis

9. 9A patient with deeply pigmented skin uses greasy hair products and develops comedones concentrated along the hairline. Which explanation is most likely?

   1. A.Inflammatory follicular rupture
   2. B.Pomade-related follicular pluggingCorrect answer: B
   3. C.Friction-related follicular injury
   4. D.Drug-induced follicular inflammation

   Explanation: DermNet states: "The use of greasy hair products leads to follicular plugging and comedones along the hairline." The distribution and exposure indicate pomade acne.

   Reference: DermNet: Acne vulgaris — Acne in skin of colour

10. 10Lidocaine is infiltrated before excision of a benign skin lesion. Which channel block prevents propagation of the nerve impulse?

    1. A.Voltage-gated potassium channels
    2. B.Ligand-gated chloride channels
    3. C.Voltage-gated calcium channels
    4. D.Voltage-gated sodium channelsCorrect answer: D

    Explanation: DermNet states: "LAs are lipophilic molecules that block voltage-gated sodium channels in the nerve membrane" Sodium-channel blockade prevents depolarisation and action-potential propagation.

    Reference: DermNet: Local anaesthesia — Mechanism