Six weeks after starting hydrochlorothiazide, a woman develops annular, scaly, polycyclic plaques with central clearing over the upper back, the V of the neck and the outer arms. They flare after sun exposure and fade without scarring. KOH mount is negative and anti-Ro (SS-A) is positive. What is the most likely diagnosis?

Drug-induced subacute cutaneous lupus

Ash-leaf macules seen under a Wood lamp, red papules over the nose and cheeks, a leathery plaque on the lower back and seizures since infancy are found in a teenage boy. His parents ask for a cream to reduce the facial papules. Which topical drug targets the cause?

Tacrolimus, a calcineurin inhibitor

Two years after a single depigmented patch appeared along the right side of the forehead and upper eyelid of a 20-year-old student, it has not changed in size and no new patches have appeared anywhere; the eyelashes in the patch are white. She has used tacrolimus ointment, a potent topical steroid and 6 months of targeted excimer light with almost no repigmentation. There is no family history of vitiligo or thyroid disease, and her thyroid function and TPO antibodies are normal. She wants a lasting cosmetic result before her wedding. What is the most appropriate next step?

Autologous melanocyte-keratinocyte transplantation

Narrowband UVB to the whole body for a year

Monobenzone cream to depigment the rest of the face

Hydroxychloroquine 200 mg twice daily was started 4 months ago for discoid lupus on the face and scalp of a hotel receptionist weighing 72 kg. The plaques are still active despite good adherence and sunscreen use. She smokes about ten cigarettes a day. Which step is most likely to improve her response?

Add chloroquine to hydroxychloroquine

Increase hydroxychloroquine to 800 mg daily

Stop the drug and use topical steroid alone

Autoimmune, vascular and genetic skin disease; biologics

23 NEET-PG practice questions on Autoimmune, vascular and genetic skin disease; biologics, part of Dermatology. The first 23 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

Question 1 · Medium
Six weeks after starting hydrochlorothiazide, a woman develops annular, scaly, polycyclic plaques with central clearing over the upper back, the V of the neck and the outer arms. They flare after sun exposure and fade without scarring. KOH mount is negative and anti-Ro (SS-A) is positive. What is the most likely diagnosis?
1. ATinea corporis
2. BDrug-induced subacute cutaneous lupus
3. CDiscoid lupus erythematosus
4. DErythema annulare centrifugum
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Answer: B · Drug-induced subacute cutaneous lupus
Photo-distributed annular or psoriasiform plaques that heal without scarring and go with anti-Ro antibodies are subacute cutaneous lupus erythematosus (SCLE). Thiazides are the classic trigger; terbinafine, PPIs, calcium channel blockers and TNF inhibitors also induce it. Stopping the drug and strict sun protection usually clear it within weeks. Key point: Annular photosensitive plaques without scarring, anti-Ro positive, after a thiazide: drug-induced SCLE.
- A: The negative KOH and anti-Ro positivity argue against tinea.
- C: DLE scars and leaves atrophy and dyspigmentation.
- D: Erythema annulare centrifugum has a trailing scale and no anti-Ro.
Question 2 · Medium
Ash-leaf macules seen under a Wood lamp, red papules over the nose and cheeks, a leathery plaque on the lower back and seizures since infancy are found in a teenage boy. His parents ask for a cream to reduce the facial papules. Which topical drug targets the cause?
1. ATretinoin, a retinoid
2. BSirolimus, an mTOR inhibitor
3. CTacrolimus, a calcineurin inhibitor
4. DImiquimod, a TLR7 agonist
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Answer: B · Sirolimus, an mTOR inhibitor
Ash-leaf macules, facial angiofibromas, a shagreen patch and seizures are tuberous sclerosis complex, caused by TSC1 (hamartin) or TSC2 (tuberin) mutations. Loss of this complex leaves mTOR permanently switched on, which drives the hamartomas. Topical sirolimus (rapamycin) shrinks and lightens angiofibromas, and oral everolimus is used for SEGA and renal angiomyolipomas. Key point: Tuberous sclerosis is mTOR overactivity; topical sirolimus treats facial angiofibromas.
- A: Tretinoin does not shrink angiofibromas.
- C: Tacrolimus does not act on the mTOR pathway.
- D: Imiquimod is used for warts and superficial BCC, not angiofibromas.
Question 3 · Hard
Two years after a single depigmented patch appeared along the right side of the forehead and upper eyelid of a 20-year-old student, it has not changed in size and no new patches have appeared anywhere; the eyelashes in the patch are white. She has used tacrolimus ointment, a potent topical steroid and 6 months of targeted excimer light with almost no repigmentation. There is no family history of vitiligo or thyroid disease, and her thyroid function and TPO antibodies are normal. She wants a lasting cosmetic result before her wedding. What is the most appropriate next step?
1. ANarrowband UVB to the whole body for a year
2. BOral mini-pulse betamethasone
3. CAutologous melanocyte-keratinocyte transplantation
4. DMonobenzone cream to depigment the rest of the face
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Answer: C · Autologous melanocyte-keratinocyte transplantation
A unilateral, dermatomal patch that spread quickly and then stopped is segmental vitiligo; white hairs (leukotrichia) mean the follicular melanocyte reservoir is lost, so medical treatment and phototherapy rarely work. Because the disease has been stable for over a year and segmental vitiligo seldom relapses, surgery gives the best result: non-cultured epidermal cell suspension (melanocyte-keratinocyte transplant), suction blister or punch grafts. Key point: Stable segmental vitiligo with leukotrichia responds poorly to drugs; offer surgical grafting.
- A: Whole-body phototherapy is unnecessary for one patch and fails with leukotrichia.
- B: Mini-pulse steroids stop spreading disease and add nothing to stable vitiligo.
- D: Depigmentation is for near-universal vitiligo, not one stable patch.
Question 4 · Easy
Violaceous flat-topped papules over the knuckles with a heliotrope rash of both eyelids point to which disease?
1. ASystemic lupus erythematosus
2. BDermatomyositis
3. CSystemic sclerosis
4. DLichen planus
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Answer: B · Dermatomyositis
Gottron papules over the knuckles and a violet heliotrope rash of the upper eyelids are the hallmark skin signs of dermatomyositis. Other signs are the shawl and V signs, ragged cuticles with dilated nailfold capillaries and 'mechanic's hands'. In lupus, the rash on the hands typically spares the knuckles and lies between them. Key point: Gottron papules on the knuckles and a heliotrope rash: dermatomyositis.
- A: Lupus rash on the hands lies between the knuckles, sparing them.
- C: Systemic sclerosis gives skin thickening, sclerodactyly and Raynaud phenomenon.
- D: Lichen planus papules are polygonal and itchy on the wrists, not periorbital.
Question 5 · Medium
Hydroxychloroquine 200 mg twice daily was started 4 months ago for discoid lupus on the face and scalp of a hotel receptionist weighing 72 kg. The plaques are still active despite good adherence and sunscreen use. She smokes about ten cigarettes a day. Which step is most likely to improve her response?
1. AAdd chloroquine to hydroxychloroquine
2. BStop smoking
3. CIncrease hydroxychloroquine to 800 mg daily
4. DStop the drug and use topical steroid alone
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Answer: B · Stop smoking
Smoking roughly halves the response of cutaneous lupus to antimalarials and also worsens the disease, so quitting is the first, cheapest step. Chloroquine and hydroxychloroquine must never be combined because retinal toxicity adds up, and the hydroxychloroquine dose should stay at or below 5 mg/kg of actual body weight daily. Baseline and yearly eye screening are needed. Key point: Smoking blunts the response of cutaneous lupus to hydroxychloroquine; ask them to quit before escalating.
- A: Combining the two antimalarials sharply raises the risk of retinopathy.
- C: 800 mg daily exceeds the safe 5 mg/kg limit and risks retinopathy.
- D: Topical steroid alone is unlikely to control widespread active DLE.
Question 6 · Medium
Ruxolitinib 1.5% cream is prescribed twice daily for non-segmental vitiligo of the face in a young software engineer. Which signalling step does it block in the skin?
1. ABreakdown of cyclic AMP by phosphodiesterase 4
2. BBinding of IL-17A to its receptor
3. CCalcineurin-dependent activation of T cells
4. DJAK1 and JAK2 signalling downstream of interferon-gamma
Answer and explanation in LearnFree account
Question 7 · Medium
Dupilumab is started for severe atopic dermatitis in a young woman whose disease relapsed after cyclosporine. She asks which side effect she is most likely to notice. What should she be told?
1. AReactivation of latent tuberculosis
2. BRaised blood pressure and creatinine
3. CHerpes zoster and venous thrombosis
4. DConjunctivitis and dry, itchy eyes
Answer and explanation in LearnFree account
Question 8 · Medium
CK 2,400 U/L (normal under 200) in a woman of 56 who has had difficulty climbing stairs and combing her hair for 2 months. She has a violet rash on both upper eyelids, scaly red papules over the knuckles and a red rash over the upper back and shoulders. Muscle biopsy confirms the diagnosis and prednisolone is started. Which further step is most important?
1. ATest for anti-dsDNA and serum complement
2. BStart methotrexate and stop the steroid
3. CScreen for an underlying cancer, especially ovarian
4. DArrange nerve conduction studies
Answer and explanation in LearnFree account
Question 9 · Easy
Palpable purpura over the buttocks and legs, colicky abdominal pain and knee pain appear in a boy of 6, two weeks after a sore throat. Platelets are 2.8 lakh/µL. On direct immunofluorescence of a skin biopsy, which immunoglobulin would line the vessel walls?
1. AIgA
2. BIgM
3. CIgG
4. DIgE
Answer and explanation in LearnFree account
Question 10 · Hard
Painful red papules on the palmar creases and finger pads, ulcers over the knuckles and elbows, and a faint heliotrope rash have appeared over 2 months in a woman from Kochi. Her strength is normal and CK is 150 U/L (normal under 200). In the past 3 weeks she has become breathless on walking, with fine bibasal crackles and SpO2 91% on room air, and HRCT shows lower-lobe ground-glass change with consolidation. Serum ferritin is 1,850 ng/mL, ANA is weakly positive and sputum cultures are negative after a week of antibiotics. Which antibody is most likely positive?
1. AAnti-MDA5
2. BAnti-Mi-2
3. CAnti-Jo-1
4. DAnti-TIF1-gamma
Answer and explanation in LearnFree account
Question 11 · Medium
Large, dark brown, polygonal scales over the trunk, neck and outer limbs, sparing the palms, soles and flexures, have been present since early infancy in a boy now 9. A maternal uncle has the same skin. His mother's labour with him was prolonged and needed a caesarean section, and slit-lamp examination shows faint comma-shaped corneal opacities. Deficiency of which enzyme is most likely?
1. ASteroid sulfatase
2. B21-hydroxylase
3. CTransglutaminase 1
4. DFatty aldehyde dehydrogenase
Answer and explanation in LearnFree account
Question 12 · Easy
Besides six or more cafe-au-lait macules, which skin finding supports a diagnosis of neurofibromatosis type 1?
1. APort-wine stain
2. BAsh-leaf macules
3. CFacial angiofibromas
4. DAxillary freckling
Answer and explanation in LearnFree account
Question 13 · Medium
A skin biopsy of palpable purpura on the legs of a man who started amoxicillin 10 days ago shows neutrophils in and around the walls of small dermal venules, fibrinoid necrosis and scattered nuclear dust, with extravasated red cells. What is the pathological term?
1. AGranulomatous vasculitis
2. BLeukocytoclastic vasculitis
3. CSeptal panniculitis
4. DThrombotic vasculopathy
Answer and explanation in LearnFree account
Question 14 · Medium
Statements on oral JAK inhibitors in dermatology: 1. Baricitinib is approved for severe alopecia areata. 2. Herpes zoster is a recognised adverse effect. 3. They act by blocking the IL-4 receptor alpha chain. 4. They carry warnings of thrombosis, major cardiovascular events and malignancy. Which are correct?
1. A1 and 3 only
2. B1, 2, 3 and 4
3. C1, 2 and 4 only
4. D2, 3 and 4 only
Answer and explanation in LearnFree account
Question 15 · Medium
Genes and inherited skin disorders: 1. Epidermolysis bullosa simplex: keratin 5 or 14. 2. Dominant or recessive dystrophic epidermolysis bullosa: type VII collagen. 3. Ichthyosis vulgaris: filaggrin. 4. X-linked ichthyosis: transglutaminase 1. Which pairs are correct?
1. A1, 2 and 3 only
2. B1 and 2 only
3. C1, 3 and 4 only
4. D2, 3 and 4 only
Answer and explanation in LearnFree account
Question 16 · Medium
Generalised non-segmental vitiligo covering about 25% of the body surface has kept spreading for 6 months in a college student despite twice-daily topical mometasone and tacrolimus. New macules keep appearing at sites of friction. Which treatment is preferred next?
1. ANarrowband UVB phototherapy
2. BOral psoralen with sunlight (PUVAsol)
3. CMonobenzone depigmentation therapy
4. DSuction blister epidermal grafting
Answer and explanation in LearnFree account
Question 17 · Hard
Chronic plaque psoriasis covering 20% of the body (PASI 18) has failed methotrexate and acitretin in a bank officer, who also has Crohn disease of the terminal ileum, currently quiet on azathioprine. His latent TB screen is negative. Which biologic is the best choice for both conditions?
1. AApremilast
2. BEtanercept
3. CSecukinumab
4. DUstekinumab
Answer and explanation in LearnFree account
Question 18 · Medium
At the 6-week immunisation visit, a baby girl has annular red scaly plaques around both eyes and on the scalp, and her heart rate is a steady 54/min. The mother has had dry eyes and a dry mouth for a year but has no diagnosis. Which maternal antibody explains both the rash and the slow heart rate?
1. AAnti-dsDNA
2. BAnti-Ro (SS-A)
3. CAnti-Smith
4. DAnti-centromere
Answer and explanation in LearnFree account
Question 19 · Hard
Flaccid blisters that rupture into painful erosions on the trunk, with extensive oral ulcers, have been present for 3 months in a tea-estate supervisor; firm sideways pressure on normal skin shears off the epidermis. Direct immunofluorescence shows intercellular IgG in a fishnet pattern within the epidermis. After 6 weeks of prednisolone 1 mg/kg/day, new blisters still appear, and his fasting glucose has risen to 210 mg/dL. Which is the best next step?
1. ARaise prednisolone to 2 mg/kg/day
2. BAdd rituximab
3. CAdd dapsone
4. DSwitch to omalizumab
Answer and explanation in LearnFree account
Question 20 · Medium
Patches of scarring alopecia with follicular plugging, central atrophy and white depigmentation ringed by dark pigment on the scalp, along with similar plaques in the conchae of both ears, are seen in a woman of 32. What is the most likely diagnosis?
1. AAlopecia areata
2. BDiscoid lupus erythematosus
3. CLichen planopilaris
4. DTinea capitis
Answer and explanation in LearnFree account
Question 21 · Easy
Milky-white macules over the fingertips, lips and around the eyes have spread over 2 years in a tailor from Kannur; under a Wood lamp they turn chalk-white with sharp borders. What would a biopsy from a patch most likely show?
1. ANormal melanocyte count with less melanin
2. BYeasts and hyphae in the stratum corneum
3. CAbsence of melanocytes in the basal layer
4. DGranulomas around dermal nerves
Answer and explanation in LearnFree account
Question 22 · Medium
As the dermatologist at a district hospital planning adalimumab for severe chronic plaque psoriasis in a mill worker whose disease failed methotrexate and phototherapy, which test is essential before the first dose?
1. AHLA-B27 and HLA-Cw6 typing
2. BSerum ANA and anti-dsDNA titres
3. CSerum IgE and eosinophil count
4. DIGRA or tuberculin test with chest X-ray
Answer and explanation in LearnFree account
Question 23 · Medium
Tender nodules along the legs, livedo racemosa, a right foot drop and new hypertension of 170/104 mmHg develop over 3 months in a lorry driver who is HBsAg positive. Urine shows no red cell casts, ANCA is negative and the chest X-ray is clear. What is the most likely diagnosis?
1. AMicroscopic polyangiitis
2. BCryoglobulinaemic vasculitis
3. CPolyarteritis nodosa
4. DGranulomatosis with polyangiitis
Answer and explanation in LearnFree account

Autoimmune, vascular and genetic skin disease; biologics

Ash-leaf macules seen under a Wood lamp, red papules over the nose and cheeks, a leathery plaque on the lower back and seizures since infancy are found in a teenage boy. His parents ask for a cream to reduce the facial papules. Which topical drug targets the cause?

Violaceous flat-topped papules over the knuckles with a heliotrope rash of both eyelids point to which disease?

Ruxolitinib 1.5% cream is prescribed twice daily for non-segmental vitiligo of the face in a young software engineer. Which signalling step does it block in the skin?

Dupilumab is started for severe atopic dermatitis in a young woman whose disease relapsed after cyclosporine. She asks which side effect she is most likely to notice. What should she be told?

Palpable purpura over the buttocks and legs, colicky abdominal pain and knee pain appear in a boy of 6, two weeks after a sore throat. Platelets are 2.8 lakh/µL. On direct immunofluorescence of a skin biopsy, which immunoglobulin would line the vessel walls?

Besides six or more cafe-au-lait macules, which skin finding supports a diagnosis of neurofibromatosis type 1?

A skin biopsy of palpable purpura on the legs of a man who started amoxicillin 10 days ago shows neutrophils in and around the walls of small dermal venules, fibrinoid necrosis and scattered nuclear dust, with extravasated red cells. What is the pathological term?

Genes and inherited skin disorders: 1. Epidermolysis bullosa simplex: keratin 5 or 14. 2. Dominant or recessive dystrophic epidermolysis bullosa: type VII collagen. 3. Ichthyosis vulgaris: filaggrin. 4. X-linked ichthyosis: transglutaminase 1. Which pairs are correct?

Generalised non-segmental vitiligo covering about 25% of the body surface has kept spreading for 6 months in a college student despite twice-daily topical mometasone and tacrolimus. New macules keep appearing at sites of friction. Which treatment is preferred next?

Chronic plaque psoriasis covering 20% of the body (PASI 18) has failed methotrexate and acitretin in a bank officer, who also has Crohn disease of the terminal ileum, currently quiet on azathioprine. His latent TB screen is negative. Which biologic is the best choice for both conditions?

At the 6-week immunisation visit, a baby girl has annular red scaly plaques around both eyes and on the scalp, and her heart rate is a steady 54/min. The mother has had dry eyes and a dry mouth for a year but has no diagnosis. Which maternal antibody explains both the rash and the slow heart rate?

Patches of scarring alopecia with follicular plugging, central atrophy and white depigmentation ringed by dark pigment on the scalp, along with similar plaques in the conchae of both ears, are seen in a woman of 32. What is the most likely diagnosis?

Milky-white macules over the fingertips, lips and around the eyes have spread over 2 years in a tailor from Kannur; under a Wood lamp they turn chalk-white with sharp borders. What would a biopsy from a patch most likely show?

As the dermatologist at a district hospital planning adalimumab for severe chronic plaque psoriasis in a mill worker whose disease failed methotrexate and phototherapy, which test is essential before the first dose?

Tender nodules along the legs, livedo racemosa, a right foot drop and new hypertension of 170/104 mmHg develop over 3 months in a lorry driver who is HBsAg positive. Urine shows no red cell casts, ANCA is negative and the chest X-ray is clear. What is the most likely diagnosis?