Page 18 of 21
DR2.1,DR3.1-3,DR4.1 | Papulosquamous & Pigmentary Disorders — Practice Quiz
Click any question card to reveal the correct answer.
A 35-year-old man presents with well-demarcated erythematous plaques covered with silvery-white scale over both elbows and knees for 6 months. When the adherent scale is scraped with a glass slide, thin flakes are initially removed easily (like candle grease), and further scraping reveals a shiny, smooth surface followed by pinpoint bleeding points. Which sequence of findings is being described?
Correct. The Grattage test (Brocq's method) elicits signs in sequence: first the silvery scale flakes off like candle grease, then a shiny last-membrane surface is exposed, and finally gentle scraping reveals Auspitz sign — pinpoint bleeding from dilated capillaries in elongated dermal papillae.
The Grattage test in psoriasis yields three sequential endpoints: candle-grease sign (parakeratotic scale), the last membrane (pellucid), then Auspitz sign (pinpoint bleeding from dilated dermal papillary capillaries). Nikolsky and Wickham striae belong to pemphigus and lichen planus respectively.
Incorrect. The Grattage test is a bedside procedure specific to psoriasis that elicits three endpoints in order. Candle-grease sign is the first (parakeratotic scale), followed by the last membrane, then Auspitz sign (pinpoint bleeding). Koebner is isomorphism at trauma sites; Nikolsky sign is splitting in pemphigus; Wickham striae are the white lace markings of lichen planus.
Click to reveal answer
A 28-year-old woman is seen in dermatology OPD with pruritic, flat-topped, violaceous papules over the flexor aspect of both wrists. Close inspection with a magnifying glass reveals a fine lace-like white network on the surface. Oral examination shows asymptomatic white reticulate streaks on the buccal mucosa. Which clinical sign is directly visualised in this case?
Correct. Wickham striae are pathognomonic surface markings of lichen planus, seen as a fine white lace-like network on the flat-topped violaceous papules. They are best seen with a magnifying glass or dermoscope, and the oral counterpart is reticulate white streaks on the buccal mucosa.
Wickham striae — the fine white lace-like network visible on the surface of lichen planus papules (and as reticulate white streaks on oral mucosa) — are pathognomonic of lichen planus and reflect focal hypergranulosis of the epidermis.
Incorrect. The white lace-like network on the surface of flat-topped violaceous papules is Wickham striae — the hallmark sign of lichen planus, reflecting focal hypergranulosis. Auspitz sign is pinpoint bleeding in psoriasis; Koebner phenomenon is new lesions at trauma sites; Nikolsky sign is epidermal sliding in pemphigus.
Click to reveal answer
A 42-year-old man with a 2-year history of psoriasis vulgaris involving 35% BSA is being considered for systemic therapy. He has controlled hypertension and mild renal impairment (creatinine 1.6 mg/dL). Which statement about systemic therapy in this patient is MOST accurate?
Correct. Systemic corticosteroids are absolutely contraindicated in psoriasis because withdrawal routinely triggers a severe rebound — either generalised pustular psoriasis or erythroderma, both potentially life-threatening. Approved systemic options include methotrexate, cyclosporine, acitretin, and biologics.
Systemic corticosteroids are contraindicated in psoriasis — their withdrawal can trigger generalised pustular psoriasis (von Zumbusch type) or erythroderma. First-line systemic agents are methotrexate, cyclosporine, and acitretin. This is a hard contraindication, not a relative one.
Incorrect. Systemic corticosteroids are CONTRAINDICATED in psoriasis — this is a hard rule, not dose-dependent. Steroid withdrawal can precipitate generalised pustular psoriasis or erythroderma. The correct first-line systemic agents are methotrexate, cyclosporine, or acitretin.
Click to reveal answer
A 22-year-old medical student notices several milky-white, well-demarcated patches over the dorsum of both hands and around the mouth, present for 8 months and slowly enlarging. Wood's lamp examination shows brilliant white fluorescence accentuating the patches. There is no anaesthesia, no surface change, and no atrophy. What is the most likely diagnosis?
Correct. Vitiligo produces sharply demarcated, milky-white DEPIGMENTED macules that fluoresce brilliantly under Wood's lamp (accentuation sign). The distribution (perioral, acral) and age of onset are classic. Absence of anaesthesia excludes leprosy; absence of scale or KOH positivity excludes pityriasis versicolor.
Vitiligo produces DEPIGMENTED (not hypopigmented) milky-white macules with a sharp border; Wood's lamp brilliantly accentuates them due to absence of melanin. The absence of anaesthesia excludes leprosy, the absence of scale excludes pityriasis versicolor, and the milky-white colour (not off-white/dull) distinguishes from post-inflammatory hypopigmentation.
Incorrect. The key discriminating features here are: (1) milky-white (not dull/off-white) colour indicating complete depigmentation, (2) brilliant Wood's lamp fluorescence, and (3) no anaesthesia/scale/atrophy. Together these point to vitiligo. Leprosy causes hypo- (not de-)pigmentation with anaesthesia; pityriasis versicolor has fine scale and KOH-positive hyphae; post-inflammatory lesions are hypopigmented and irregular.
Click to reveal answer
A 30-year-old patient with psoriasis vulgaris (BSA 8%) presents requesting treatment. Lesions are limited to the elbows, knees, and scalp. Which first-line treatment is most appropriate for this severity and distribution?
Correct. BSA 8% (< 10%) with limited distribution is mild-to-moderate psoriasis managed with topical agents. The combination of a potent topical corticosteroid with calcipotriol (vitamin D analogue) is evidence-based first-line treatment; the combination reduces the total corticosteroid burden and has additive efficacy.
Limited psoriasis (BSA <10%, PASI <10) is treated with topical agents — potent/super-potent topical corticosteroids (avoiding face/flexures), vitamin D analogues (calcipotriol), coal tar, salicylic acid for thick plaques, or combinations. Phototherapy and systemic agents are reserved for moderate-severe disease. Systemic steroids are absolutely contraindicated.
Incorrect. BSA 8% classifies as limited disease, which is managed first-line with topical agents — potent corticosteroids ± calcipotriol. Phototherapy (NB-UVB) and systemic agents (methotrexate, cyclosporine) are for moderate-severe disease (BSA >10% or PASI >10). Systemic corticosteroids are absolutely contraindicated in psoriasis.
Click to reveal answer
A patient with lichen planus presents with moderately severe disease involving the flexor wrists and trunk with significant pruritus. You plan to prescribe systemic corticosteroids. Which statement CORRECTLY distinguishes this management decision from the treatment rule in psoriasis?
Correct. The hard contraindication to systemic steroids is psoriasis-specific — withdrawal reliably triggers pustular psoriasis or erythroderma. Lichen planus is a T-cell-mediated lichenoid disease where systemic corticosteroids suppress the immune attack and are appropriate for moderate-severe or widespread disease.
Systemic corticosteroids are contraindicated in psoriasis (rebound triggers pustular/erythrodermic flare) but are legitimate first-line systemic therapy for moderate-severe lichen planus. This contrast is a key clinical distinction between the two papulosquamous diseases.
Incorrect. The contraindication to systemic steroids applies to PSORIASIS, not lichen planus. In psoriasis, steroid withdrawal triggers generalised pustular psoriasis or erythroderma. In lichen planus (a T-cell lichenoid reaction), systemic corticosteroids appropriately suppress the immune-mediated destruction and are an accepted systemic treatment.
Click to reveal answer
A 45-year-old woman is evaluated for pale patches on her face and forearms. You perform Wood's lamp examination. Which finding would MOST strongly favour vitiligo over paucibacillary leprosy (tuberculoid type)?
Correct. The brilliant chalk-white fluorescence on Wood's lamp reflects complete absence of melanin (depigmentation, not hypopigmentation). Normal sensation (no hypoaesthesia) excludes leprosy. Together these clinch vitiligo. Leukotrichia (white hair) within the patch is further supporting evidence when present.
Vitiligo produces COMPLETE depigmentation — brilliant chalk-white on Wood's lamp, normal sensation, and (in active vitiligo) leukotrichia if hair follicle melanocytes are destroyed. Tuberculoid leprosy produces hypopigmented (not milky-white), hypoaesthetic/anaesthetic patches with dry surface (anhidrosis). KOH-positive pseudohyphae indicate pityriasis versicolor.
Incorrect. The two most discriminating features are: (1) colour quality — milky-white/chalk-white (depigmented) versus dull off-white (hypopigmented), and (2) sensation — normal in vitiligo, reduced in leprosy. Wood's lamp accentuates vitiligo brilliantly. KOH positivity points to pityriasis versicolor, not vitiligo or leprosy.
Click to reveal answer
A 19-year-old male presents with sudden onset of multiple, small (0.5–1.5 cm), drop-like, scaly erythematous lesions widely distributed over the trunk and proximal limbs following an episode of streptococcal pharyngitis 3 weeks ago. Which variant of psoriasis is this most consistent with?
Correct. Guttate psoriasis is characterised by the sudden eruption of numerous small ('drop-like') erythematous scaly lesions widely distributed over the trunk, typically triggered 2–4 weeks after Group A streptococcal infection in young patients. The Greek word 'gutta' means drop.
Guttate ('drop-like') psoriasis is the second most common variant — small, scattered, teardrop-shaped plaques over the trunk following Group A streptococcal infection (pharyngitis or perianal), typically in children and young adults. Most resolve spontaneously or with antibiotics; some evolve to chronic plaque disease.
Incorrect. Post-streptococcal, widespread, small drop-like lesions in a young adult is the classic presentation of guttate psoriasis. Erythroderma involves >90% BSA with generalised redness and scaling; inverse psoriasis affects body folds (minimal scale); generalised pustular psoriasis (von Zumbusch) presents with sterile pustules on an erythematous background and systemic upset.
Click to reveal answer
During a ward exam, a student is asked to identify and perform the Grattage test on a patient with suspected psoriasis. After removing the first layer of scale (candle-grease sign), the student should next observe for which finding before proceeding to the final endpoint?
Correct. The three-step sequence is: candle-grease sign → last membrane (smooth, shiny, pellucid surface) → Auspitz sign (pinpoint bleeding). The last membrane represents the attenuated suprapapillary epidermis and must be visualised before further scraping to confirm the diagnosis sequence properly.
The Grattage test has three sequential endpoints in order: (1) candle-grease sign — flaky scale, (2) last membrane — smooth, shiny, semi-transparent surface after the granular layer is exposed, then (3) Auspitz sign — pinpoint bleeding from dilated papillary capillaries. Stopping at the first or second step is incomplete; digging hard beyond the last membrane is a procedural error that produces non-specific bleeding.
Incorrect. The Grattage test proceeds in strict sequence: after the candle-grease sign (scale removal), the next landmark is the last membrane — a smooth, shiny, semi-transparent surface representing the thinned suprapapillary epidermis. Only after this is gently scraped does Auspitz sign (pinpoint bleeding) appear. Nikoksy sign and Wickham striae are not part of the Grattage test.
Click to reveal answer
A 38-year-old woman with stable vitiligo on the hands and face for 3 years asks about treatment options. She is not planning pregnancy. Dermatology outpatient assessment confirms segmental vitiligo affecting 5% BSA, stable for 18 months (no new lesions). Which statement about the treatment of this patient is MOST accurate?
Correct. Stable segmental vitiligo with limited BSA is the ideal indication for surgical repigmentation (punch grafting, split-thickness grafting, melanocyte-keratinocyte transplantation). Topical corticosteroids or calcineurin inhibitors are appropriate for localised lesions. Oral minipulse steroids are reserved for active/spreading vitiligo to arrest progression.
Vitiligo treatment is stratified by extent and stability. For stable localised vitiligo, topical agents (class II–III corticosteroids or topical calcineurin inhibitors — tacrolimus, pimecrolimus) are first-line. Stable segmental vitiligo is the BEST candidate for surgical repigmentation (split skin graft, punch grafting, melanocyte transfer). NB-UVB is used for widespread/active disease. Oral minipulse steroids stabilise active/spreading disease.
Incorrect. Treatment for vitiligo is tailored by extent, activity, and site. Localised stable disease: topical corticosteroids or tacrolimus. Stable segmental vitiligo: surgical repigmentation is most effective (punch grafting, MKTP). Active/spreading disease: oral dexamethasone minipulse to halt progression. NB-UVB is appropriate for widespread active/stable disease, not contraindicated.
Click to reveal answer