A 34-year-old man with lepromatous leprosy is in his fifth month of multibacillary MDT. He now has fever, joint pains and crops of painful, tender red nodules on his arms and thighs, each lasting a few days. His old skin lesions are unchanged, and both ulnar nerves are tender. What is the most likely diagnosis?

Dapsone hypersensitivity syndrome

A 68-year-old woman has had burning pain over the right side of her chest for 3 days, and now has clusters of vesicles on a red base in a band that stops at the midline. A Tzanck smear is made from the floor of a fresh vesicle. What will it show?

Acantholytic keratinocytes only

A 22-year-old gym trainer from Chennai has many small hypopigmented macules on his upper back and chest that join in places. Scratching a lesion lifts a fine, bran-like scale. They itch a little when he sweats. What will a KOH mount of the scale most likely show?

Short hyphae with clusters of round yeasts

Budding yeasts with pseudohyphae

Long septate hyphae with arthroconidia

A 3-year-old boy has fever and irritability, then tender, bright red skin that starts around the mouth and in the flexures. Within a day large areas wrinkle and peel, leaving moist raw skin; gentle rubbing of normal-looking skin shears it off. The lips have radial crusts but the oral mucosa is normal. What causes the skin splitting?

Exfoliative toxin cleaving desmoglein 1

IgG autoantibodies against BP180

Drug-induced keratinocyte apoptosis

IgG autoantibodies against desmoglein 3

Leprosy and skin infections

20 NEET-PG practice questions on Leprosy and skin infections, part of Dermatology. The first 20 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
A 34-year-old man with lepromatous leprosy is in his fifth month of multibacillary MDT. He now has fever, joint pains and crops of painful, tender red nodules on his arms and thighs, each lasting a few days. His old skin lesions are unchanged, and both ulnar nerves are tender. What is the most likely diagnosis?
1. AType 1 (reversal) reaction
2. BDapsone hypersensitivity syndrome
3. CErythema nodosum leprosum
4. DLucio phenomenon
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Answer: C · Erythema nodosum leprosum
Erythema nodosum leprosum is the type 2 lepra reaction, an immune-complex (type III) reaction seen in borderline lepromatous and lepromatous leprosy, often during treatment. Crops of evanescent tender nodules with fever, arthralgia and neuritis are typical, while the existing lesions stay as they were. Severe ENL is treated with systemic steroids, and high-dose clofazimine or thalidomide in recurrent cases; MDT is continued throughout.
- A: A type 1 reaction inflames the existing lesions and occurs in borderline leprosy, without crops of new nodules.
- B: Dapsone syndrome appears in the first weeks with rash, hepatitis and lymphadenopathy, not tender nodules.
- D: Lucio phenomenon causes necrotic ulcers in diffuse non-nodular lepromatous leprosy.
Question 2 · Easy
A 68-year-old woman has had burning pain over the right side of her chest for 3 days, and now has clusters of vesicles on a red base in a band that stops at the midline. A Tzanck smear is made from the floor of a fresh vesicle. What will it show?
1. AMultinucleated giant cells
2. BAcantholytic keratinocytes only
3. CDonovan bodies in macrophages
4. DHenderson-Patterson bodies
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Answer: A · Multinucleated giant cells
Unilateral dermatomal grouped vesicles after prodromal pain are herpes zoster, from reactivation of varicella-zoster virus in a sensory ganglion. A Tzanck smear from a fresh vesicle shows multinucleated giant cells with nuclear moulding, a change shared by herpes simplex and varicella-zoster viruses. The test cannot tell the two viruses apart; PCR does. Oral antivirals within 72 hours of the rash shorten the attack.
- B: Acantholytic cells without giant cells are the Tzanck finding of pemphigus.
- C: Donovan bodies are seen in donovanosis, a bacterial genital ulcer.
- D: Henderson-Patterson bodies are the inclusion bodies of molluscum contagiosum.
Question 3 · Medium
A 22-year-old gym trainer from Chennai has many small hypopigmented macules on his upper back and chest that join in places. Scratching a lesion lifts a fine, bran-like scale. They itch a little when he sweats. What will a KOH mount of the scale most likely show?
1. AShort hyphae with clusters of round yeasts
2. BAcid-fast bacilli in clumps
3. CBudding yeasts with pseudohyphae
4. DLong septate hyphae with arthroconidia
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Answer: A · Short hyphae with clusters of round yeasts
Hypopigmented, finely scaling macules on the upper trunk of a young adult in a hot, humid climate are pityriasis versicolor, caused by Malassezia. KOH shows short, curved hyphae with clusters of round spores, the 'spaghetti and meatballs' pattern. Azelaic acid made by the yeast inhibits melanocytes, which is why the macules are pale. Topical ketoconazole or selenium sulphide treats it, but pigment takes months to recover.
- B: Acid-fast bacilli are seen in leprosy, which gives anaesthetic, not scaly, patches.
- C: Budding yeast with pseudohyphae is Candida, which favours moist folds.
- D: Long branching septate hyphae with arthroconidia are dermatophytes.
Question 4 · Medium
A 3-year-old boy has fever and irritability, then tender, bright red skin that starts around the mouth and in the flexures. Within a day large areas wrinkle and peel, leaving moist raw skin; gentle rubbing of normal-looking skin shears it off. The lips have radial crusts but the oral mucosa is normal. What causes the skin splitting?
1. AIgG autoantibodies against BP180
2. BDrug-induced keratinocyte apoptosis
3. CIgG autoantibodies against desmoglein 3
4. DExfoliative toxin cleaving desmoglein 1
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Answer: D · Exfoliative toxin cleaving desmoglein 1
This is staphylococcal scalded skin syndrome. Exfoliative toxins A and B from a distant focus of S. aureus are serine proteases that cleave desmoglein 1, splitting the epidermis high, at the granular layer. Desmoglein 1 is scarce in mucous membranes, so mucosae are spared, which separates SSSS from toxic epidermal necrolysis. Children recover quickly without scarring on antistaphylococcal antibiotics such as cloxacillin, with fluid and skin care.
- A: Anti-BP180 antibodies cause bullous pemphigoid, an elderly subepidermal blistering disease.
- B: Keratinocyte apoptosis is TEN, which gives full-thickness necrosis with mucosal involvement.
- C: Anti-desmoglein 3 antibodies cause pemphigus vulgaris, with prominent mucosal erosions.
Question 5 · Easy
A 5-year-old boy has had multiple pearly, dome-shaped, 2-4 mm papules with a central dimple on his trunk and axillae for 2 months. Squeezing one releases a cheesy core. To which virus family does the cause belong?
1. APicornaviridae
2. BHerpesviridae
3. CPoxviridae
4. DPapillomaviridae
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Answer: C · Poxviridae
Pearly umbilicated papules with a curd-like core are molluscum contagiosum, caused by a poxvirus. The core contains large eosinophilic intracytoplasmic inclusions (Henderson-Patterson or molluscum bodies). In children the lesions usually clear on their own over months; extensive or giant lesions in an adult should prompt an HIV test.
- A: Picornaviruses (coxsackie) cause hand-foot-mouth disease with oral ulcers and vesicles.
- B: Herpesviruses cause grouped vesicles, not firm umbilicated papules.
- D: Papillomaviruses cause warts, which are rough and not umbilicated.
Question 6 · Medium
A 6-year-old girl has had a scaly patch of broken hairs on the scalp for a month. It has now become a boggy, tender, pus-studded swelling, and she has tender occipital nodes. KOH mount of a plucked hair shows arthroconidia. What is the next best step?
1. AIncision and drainage of the swelling
2. BTopical clotrimazole for 4 weeks
3. COral griseofulvin for 6-8 weeks
4. DOral cloxacillin for 10 days
Answer and explanation in LearnFree account
Question 7 · Hard
A 33-year-old man started multibacillary MDT 5 weeks ago. He now has fever of 39 °C, a widespread itchy exfoliating rash, generalised lymphadenopathy and jaundice. Bilirubin is 4.8 mg/dL, ALT 410 U/L and the eosinophil count is 1,800/µL. His old leprosy patches are not inflamed and there are no tender nodules. What is the next best step?
1. AStop dapsone permanently and start steroids
2. BContinue MDT and add an antihistamine
3. CStop all MDT and start thalidomide
4. DContinue MDT and treat as a type 1 reaction
Answer and explanation in LearnFree account
Question 8 · Medium
A 19-year-old woman from a hostel in Pune has had a slowly enlarging, reddish-brown plaque on her right cheek for 2 years, healing with scarring at one edge while spreading at the other. Sensation over it is normal. Pressing a glass slide on it shows yellowish-brown nodules. Mantoux test gives 18 mm induration. What is the most likely diagnosis?
1. AScrofuloderma
2. BLupus vulgaris
3. CTuberculoid leprosy
4. DDiscoid lupus erythematosus
Answer and explanation in LearnFree account
Question 9 · Medium
A 34-year-old mother brings herself and her two children to the OPD with severe night-time itching. All three have papules and burrows in the finger webs and wrists. She is started on permethrin 5% cream. Four counselling points are considered: 1. All household members are treated at the same time. 2. The cream is applied from the neck down and washed off after 8-14 hours. 3. The application is repeated after one week. 4. If itching stops within two days, cure is confirmed. Which points are correct?
1. A1, 2 and 3 only
2. B1, 2 and 4 only
3. C1 and 2 only
4. D1, 3 and 4 only
Answer and explanation in LearnFree account
Question 10 · Hard
A 74-year-old bedridden woman in an old-age home in Kochi has been on oral prednisolone for 2 years for pemphigoid. For a month she has had thick, grey, warty crusts on her hands, elbows and buttocks, treated as psoriasis without benefit. She itches only mildly, but four nurses who turn her now itch at night. Scrapings of the crusts show numerous mites and eggs. What is the most appropriate management?
1. APotent topical steroid with emollients
2. BA single application of permethrin 5% cream
3. COral methotrexate for presumed psoriasis
4. DOral ivermectin with topical permethrin, and treat staff
Answer and explanation in LearnFree account
Question 11 · Medium
At a PHC in Jharkhand, a 36-year-old man has four hypoaesthetic patches on his limbs. Both the right ulnar and the left common peroneal nerves are thickened. Slit-skin smears are negative. How should he be classified and treated under NLEP?
1. APaucibacillary; MDT for 6 months
2. BMultibacillary; MDT for 24 months
3. CPaucibacillary; MDT for 12 months
4. DMultibacillary; MDT for 12 months
Answer and explanation in LearnFree account
Question 12 · Medium
A 24-year-old student in Lucknow has had itchy, ring-shaped, scaly patches on the waist and groins for 8 months. A chemist sold him a cream containing clobetasol, an antifungal and an antibacterial; the itch eased each time but the patches spread. KOH mount shows many septate hyphae. What is the most appropriate management?
1. AStop the steroid cream; start oral itraconazole
2. BContinue the same cream for another 4 weeks
3. CTopical mupirocin and an oral antihistamine
4. DOral prednisolone to control the itching
Answer and explanation in LearnFree account
Question 13 · Hard
A 47-year-old man was released from treatment after 12 months of multibacillary MDT four years ago, when his bacteriological index was 2+. Over the past 8 months, several new painless shiny papules and plaques have appeared slowly; old lesions are unchanged and he has no nerve pain or fever. A new slit-skin smear shows a BI of 3+ with many solid-staining bacilli. What is the most likely diagnosis and plan?
1. ARelapse; restart MDT and test for drug resistance
2. BErythema nodosum leprosum; thalidomide
3. CType 1 reaction; oral prednisolone
4. DDead bacilli clearing; reassure and observe
Answer and explanation in LearnFree account
Question 14 · Medium
A 28-year-old man with borderline tuberculoid leprosy is in his third month of MDT. Over a week, his old patches have become red, swollen and tender, his left hand feels numb and he cannot hold a pen well. The ulnar nerve at the elbow is thickened and tender. He has no fever and no new nodules. What is the next best step?
1. AStop MDT until the lesions settle
2. BOral prednisolone and continue MDT
3. CIncrease the dose of dapsone
4. DStart thalidomide and continue MDT
Answer and explanation in LearnFree account
Question 15 · Easy
A 52-year-old obese man with diabetes has a well-defined, reddish-brown, finely scaling patch in both groins and macerated toe webs. It is not itchy and KOH mount is negative. Under Wood's lamp the patch glows coral red. What is the causative organism?
1. ACandida albicans
2. BTrichophyton rubrum
3. CCorynebacterium minutissimum
4. DMalassezia furfur
Answer and explanation in LearnFree account
Question 16 · Medium
During a dermatology posting, an intern lists four statements about the lepromin test: 1. A positive result confirms the diagnosis of leprosy. 2. The late (Mitsuda) reaction is read at 3-4 weeks. 3. It is negative in lepromatous leprosy. 4. It reflects the patient's cell-mediated immunity to M. leprae. Which statements are correct?
1. A1, 3 and 4 only
2. B2, 3 and 4 only
3. C3 and 4 only
4. D2 and 4 only
Answer and explanation in LearnFree account
Question 17 · Medium
A 30-year-old woman from Odisha has three large, dry, anaesthetic, hypopigmented plaques on her back and thigh, with a few small satellite lesions at the edge of the largest. The right common peroneal nerve is thickened and the slit-skin smear is negative. Where does she fall on the Ridley-Jopling spectrum?
1. APolar tuberculoid leprosy
2. BMid-borderline leprosy
3. CBorderline tuberculoid leprosy
4. DBorderline lepromatous leprosy
Answer and explanation in LearnFree account
Question 18 · Medium
A 45-year-old man has diffuse infiltration of the face with loss of the lateral eyebrows and many symmetric shiny nodules on the ears. His slit-skin smear shows, on average, 10 to 100 acid-fast bacilli per oil-immersion field. What is his bacteriological index on the Ridley scale?
1. A6+
2. B5+
3. C3+
4. D4+
Answer and explanation in LearnFree account
Question 19 · Hard
A 70-year-old retired clerk has had burning pain over the left forehead for 3 days, and since yesterday grouped vesicles on the left forehead, upper eyelid and the tip and side of the nose. The eye is slightly red, and visual acuity is 6/9 in that eye. Renal function is normal. What is the next best step?
1. AOral prednisolone alone to prevent neuralgia
2. BAnalgesics and review once crusts form
3. CTopical acyclovir cream to the skin only
4. DOral acyclovir and urgent eye examination
Answer and explanation in LearnFree account
Question 20 · Easy
A 41-year-old construction worker on multibacillary MDT for 7 months says his skin patches have turned reddish-black and the skin over his shins has become dry and fish-scale-like. Liver function and haemoglobin are normal. Which drug is responsible?
1. ADapsone
2. BClofazimine
3. CRifampicin
4. DMinocycline
Answer and explanation in LearnFree account

Leprosy and skin infections

A 68-year-old woman has had burning pain over the right side of her chest for 3 days, and now has clusters of vesicles on a red base in a band that stops at the midline. A Tzanck smear is made from the floor of a fresh vesicle. What will it show?

A 22-year-old gym trainer from Chennai has many small hypopigmented macules on his upper back and chest that join in places. Scratching a lesion lifts a fine, bran-like scale. They itch a little when he sweats. What will a KOH mount of the scale most likely show?

A 5-year-old boy has had multiple pearly, dome-shaped, 2-4 mm papules with a central dimple on his trunk and axillae for 2 months. Squeezing one releases a cheesy core. To which virus family does the cause belong?

A 6-year-old girl has had a scaly patch of broken hairs on the scalp for a month. It has now become a boggy, tender, pus-studded swelling, and she has tender occipital nodes. KOH mount of a plucked hair shows arthroconidia. What is the next best step?

At a PHC in Jharkhand, a 36-year-old man has four hypoaesthetic patches on his limbs. Both the right ulnar and the left common peroneal nerves are thickened. Slit-skin smears are negative. How should he be classified and treated under NLEP?

A 52-year-old obese man with diabetes has a well-defined, reddish-brown, finely scaling patch in both groins and macerated toe webs. It is not itchy and KOH mount is negative. Under Wood's lamp the patch glows coral red. What is the causative organism?

A 45-year-old man has diffuse infiltration of the face with loss of the lateral eyebrows and many symmetric shiny nodules on the ears. His slit-skin smear shows, on average, 10 to 100 acid-fast bacilli per oil-immersion field. What is his bacteriological index on the Ridley scale?

A 41-year-old construction worker on multibacillary MDT for 7 months says his skin patches have turned reddish-black and the skin over his shins has become dry and fish-scale-like. Liver function and haemoglobin are normal. Which drug is responsible?