Dermatopathology Indian Medical PG Practice Questions and MCQs
Practice Indian Medical PG questions for Dermatopathology. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Dermatopathology Indian Medical PG Question 1: What is the primary condition for which calcitriol is used as a treatment?
- A. Pemphigus
- B. Secondary hyperparathyroidism (Correct Answer)
- C. Lichen planus
- D. Leprosy
Dermatopathology Explanation: Secondary hyperparathyroidism
- Calcitriol is the active form of vitamin D (1,25-dihydroxyvitamin D₃), and it is crucial for regulating calcium and phosphate levels in the body [1].
- In secondary hyperparathyroidism, often seen in chronic kidney disease (CKD), the kidneys cannot convert vitamin D to its active form, leading to hypocalcemia and increased PTH secretion [1], [2].
- Calcitriol supplementation helps to increase calcium absorption from the gut and suppress the release of parathyroid hormone (PTH), thereby treating the underlying cause of secondary hyperparathyroidism [1], [2].
- This is the primary therapeutic indication for calcitriol in clinical practice.
Lichen planus
- This is a chronic inflammatory condition affecting the skin, hair, nails, and mucous membranes
- Typically treated with corticosteroids or other immunosuppressants
- Calcitriol has no primary role in the treatment of lichen planus; its therapeutic applications are predominantly related to calcium and bone metabolism
Pemphigus
- Pemphigus is a group of rare autoimmune blistering diseases that affect the skin and mucous membranes
- Primary treatment involves immunosuppressants like corticosteroids, often in high doses
- Calcitriol is not indicated for the treatment of pemphigus, as its mechanism of action is unrelated to the autoimmune processes characteristic of this disease
Leprosy
- Leprosy is a chronic infectious disease caused by the bacterium Mycobacterium leprae
- Treated with multi-drug therapy (MDT), which includes antibiotics like rifampicin, dapsone, and clofazimine
- Calcitriol is not an antibiotic and therefore has no role in treating the bacterial infection responsible for leprosy
Dermatopathology Indian Medical PG Question 2: A 30-year-old woman presents with flaccid bullae on her skin that are easy to rupture. A biopsy of the lesion reveals a suprabasal split. What is the most likely diagnosis?
- A. Erythema multiforme
- B. Pemphigus vegetans
- C. Pemphigus vulgaris (Correct Answer)
- D. Pemphigus foliaceous
Dermatopathology Explanation: ***Pemphigus vulgaris***
- Characterized by **flaccid bullae** that are easily ruptured, and a classic histological finding of a **suprabasal split** in the epidermis, indicating acantholysis just above the basal layer.
- Mucosal involvement is common, and the positive **Nikolsky sign** (epidermal detachment with lateral pressure) is often present, which is typical for pemphigus vulgaris due to the superficial nature of the blistering.
- The combination of **flaccid bullae + suprabasal split** is pathognomonic for pemphigus vulgaris.
*Erythema multiforme*
- Typically presents with **targetoid lesions** (concentric rings of erythema) and is often associated with infections, particularly herpes simplex virus (HSV).
- Histologically, it shows **interface dermatitis** with vacuolar degeneration of basal cells and scattered necrotic keratinocytes, not a suprabasal split or acantholysis.
*Pemphigus vegetans*
- A rare variant of pemphigus vulgaris, it presents with **vegetating plaques** in intertriginous areas (axillae, groin), which are eroded but not primarily flaccid bullae covering wide areas.
- While it also involves a suprabasal split at the same level as pemphigus vulgaris, the clinical presentation of vegetating plaques rather than widespread flaccid bullae helps differentiate it.
*Pemphigus foliaceous*
- This autoimmune blistering disease features very **superficial bullae** that rupture so easily they typically present as erosions, crusts, and scaling rather than intact blisters.
- Histologically, it shows a **subcorneal or granular layer split** (more superficial than pemphigus vulgaris), not the deeper suprabasal split seen in this patient's biopsy.
- Mucosal involvement is **rare** in pemphigus foliaceous, unlike pemphigus vulgaris.
Dermatopathology Indian Medical PG Question 3: A 45-year-old man presents with the following skin changes (as shown in the image). What relevant history should be taken to diagnose this condition?
- A. Dementia
- B. History of dietary pattern, dementia, and diarrhea (Correct Answer)
- C. Dietary history
- D. Depression
Dermatopathology Explanation: ***History of dietary pattern, dementia, and diarrhea***
- The image displays skin changes consistent with a "Casal's necklace" pattern, characteristic of **pellagra**, a disease caused by **niacin (Vitamin B3) deficiency**.
- Pellagra is classically associated with the "3 Ds": **dermatitis** (the observed skin changes), **diarrhea**, and **dementia**. A comprehensive history should therefore include questions about dietary patterns (especially corn-based diets lacking tryptophan and niacin), gastrointestinal symptoms like diarrhea, and neurological/psychiatric symptoms indicative of dementia.
*Dementia*
- While **dementia** is one of the classic "3 Ds" of pellagra (niacin deficiency), it is only one component of the presentation and insufficient on its own to guide a complete diagnostic history for this condition.
- Focusing solely on dementia would miss crucial aspects like dietary intake and gastrointestinal symptoms that are integral to diagnosing pellagra.
*Dietary history*
- A **dietary history** is indeed very relevant for diagnosing pellagra, as it helps identify potential niacin deficiency, commonly associated with diets heavily reliant on corn without proper preparation.
- However, pellagra is not only characterized by dermatological signs and dietary insufficiency but also by gastrointestinal and neurological symptoms. Limiting the history to diet alone would therefore be incomplete.
*Depression*
- **Depression** can be a symptom of various nutritional deficiencies and other medical conditions, but it is not one of the classic "3 Ds" of pellagra, which are dermatitis, diarrhea, and dementia.
- While mood changes might be present in some patients with niacin deficiency, focusing solely on depression would not encompass the full clinical picture of pellagra and could lead to misdiagnosis.
Dermatopathology Indian Medical PG Question 4: A 70-year-old man comes to the emergency department because of a skin rash and severe itching. He appears ill; there is a generalized skin rash that is scaly, erythematous, and thickened. His palms, soles, and scalp are also involved. Which of the following is the most likely diagnosis?
- A. erythroderma (exfoliative dermatitis) (Correct Answer)
- B. pemphigus vulgaris
- C. dermatitis herpetiformis
- D. rosacea
Dermatopathology Explanation: ***erythroderma (exfoliative dermatitis)***
- Erythroderma is characterized by a **generalized erythematous (red), scaly, and thickened skin rash** covering more than 90% of the body surface, accompanied by **severe itching**.
- This condition is often associated with a **systemic illness**, and the patient's description of "appears ill" further supports this diagnosis.
*pemphigus vulgaris*
- Pemphigus vulgaris typically presents with **flaccid blisters** and erosions, particularly affecting mucous membranes, which are not described here.
- While it can be widespread, the primary lesion is a **blister** rather than diffuse erythema and scaling.
*dermatitis herpetiformis*
- Dermatitis herpetiformis is characterized by intensely **pruritic (itchy) papules and vesicles** typically found on the extensor surfaces (e.g., elbows, knees, buttocks).
- It is strongly associated with **celiac disease** and does not present as a generalized scaly, erythematous thickening.
*rosacea*
- Rosacea primarily affects the **face**, causing **erythema**, flushing, papules, and pustules, often sparing the palms, soles, and scalp.
- It is not characterized by generalized scaling, thickening, or severe itching over the entire body.
Dermatopathology Indian Medical PG Question 5: In Erythrodermic psoriasis, _____ or more of body surface area is involved
- A. 90% (Correct Answer)
- B. 85%
- C. 95%
- D. 80%
Dermatopathology Explanation: ***90%***
- Erythrodermic psoriasis is defined by the involvement of **90% or more of the total body surface area** with erythema and scaling.
- This extensive skin involvement leads to significant systemic symptoms and is considered a **medical emergency**.
- It represents the most severe form of psoriasis with near-complete body involvement.
*85%*
- While representing extensive involvement, **85%** does not meet the diagnostic threshold for erythrodermic psoriasis.
- The definition specifically requires **≥90%** body surface area involvement.
*95%*
- Although **95%** body surface area involvement would certainly qualify as erythrodermic psoriasis, it exceeds the minimum diagnostic threshold.
- The defining cutoff is **90% or more**, not 95%.
*80%*
- Involvement of **80%** of the body surface area, while extensive, does not meet the criteria for erythrodermic psoriasis.
- This would typically be classified as **severe plaque psoriasis** rather than erythrodermic form.
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