Pemphigus Vulgaris — MCQs
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 85-year-old female developed multiple blisters on the trunk and thighs. Nikolsky's sign is negative. The lesions came on and off. The most probable diagnosis is
Acantholytic cells in pemphigus are derived from:
Which of the following is NOT a characteristic of pemphigus vulgaris?
What diagnosis is suggested by the finding on the sole of this patient's foot?
Which of the following drugs can lead to pemphigus?
Which histological finding is most specific for pemphigus vulgaris?
A 50-year-old female presents with blisters and erosions on the skin and mucous membranes, most commonly inside the mouth. What is the most likely diagnosis?
Which of the following is NOT associated with erythema nodosum?
A skin biopsy shows suprabasilar acantholysis with 'row of tombstones' appearance. Which immunofluorescence pattern would confirm pemphigus vulgaris?
Pemphigus Vulgaris Indian Medical PG Practice Questions and MCQs
Question 1: 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
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.
Question 2: A 85-year-old female developed multiple blisters on the trunk and thighs. Nikolsky's sign is negative. The lesions came on and off. The most probable diagnosis is
- A. Pemphigus vulgaris
- B. Bullous pemphigoid (Correct Answer)
- C. Lepra reaction
- D. Lichen planus
Explanation: ***Bullous pemphigoid*** - The presence of **multiple tense blisters** on the trunk and thighs in an 85-year-old female, coupled with a **negative Nikolsky's sign**, is highly characteristic of bullous pemphigoid. - This condition tends to wax and wane, causing the lesions to "come on and off," and is more common in the **elderly**. *Lichen planus* - This condition presents with **pruritic, polygonal, purple, planar papules and plaques**, not blisters. - It does not typically involve the formation of **blisters** as the primary lesion nor does it involve a negative Nikolsky's sign. *Pemphigus vulgaris* - Characterized by **flaccid blisters** that rupture easily, leading to erosions, and a **positive Nikolsky's sign**. - This is in contrast to the **tense blisters** and **negative Nikolsky's sign** described in the patient. *Lepra reaction* - Refers to **acute inflammatory episodes** occurring in patients with leprosy, often presenting as **erythematous nodules** or plaques. - It does not typically involve the formation of **blisters** on the trunk and thighs in an elderly patient without a prior diagnosis of leprosy.
Question 3: Acantholytic cells in pemphigus are derived from:
- A. Stratum spinosum (Correct Answer)
- B. Stratum basale
- C. Stratum granulosum
- D. Langerhans cells
Explanation: Acantholytic cells in pemphigus are keratinocytes that have lost their desmosomal attachments due to autoimmune destruction, primarily affecting the integrity of the stratum spinosum [1]. This layer is characterized by abundant desmosomes, and their disruption leads to the characteristic intraepidermal blistering seen in pemphigus [2]. While pemphigus can affect the basal layer in some forms (like pemphigus vegetans), the primary acantholytic process occurs above this layer, leading to suprabasal cleavage [1]. The stratum granulosum lies above the stratum spinosum and contains keratohyalin granules and lamellar granules, which are essential for skin barrier function. While cells from all epidermal layers can eventually slough off, acantholysis itself primarily originates from the more adhesive cells of the stratum spinosum. Langerhans cells are dendritic antigen-presenting cells found predominantly in the stratum spinosum but are not keratinocytes. While they play a role in immune surveillance, they are not the cells that undergo acantholysis or form the bulk of the epidermal layers [3]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Skin, pp. 1170-1172. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Disorders Involving Inflammatory And Haemopoietic Cells, pp. 645-646. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Skin, p. 1144.
Question 4: Which of the following is NOT a characteristic of pemphigus vulgaris?
- A. Oral erosions
- B. Tzanck smear showing acantholytic cells
- C. Positive Nikolsky’s sign
- D. Subepidermal bulla (Correct Answer)
Explanation: ***Subepidermal bulla*** - Pemphigus vulgaris is characterized by **intraepidermal bullae** resulting from acantholysis (loss of cohesion between keratinocytes), not subepidermal bullae. - **Subepidermal bullae** are characteristic of conditions like **bullous pemphigoid**, where the split occurs below the epidermis. *Positive Nikolsky’s sign* - The **Nikolsky's sign** is positive in pemphigus vulgaris, indicating the fragility of the skin where gentle lateral pressure causes epidermal shearing. - This sign is a direct result of the **intraepidermal blistering** due to weakened cell-to-cell adhesion. *Oral erosions* - **Oral erosions** are a very common and often the initial manifestation of pemphigus vulgaris, frequently preceding skin lesions. - These painful erosions are persistent and heal slowly, sometimes making eating difficult. *Tzanck smear showing acantholytic cells* - A **Tzanck smear** from a fresh blister in pemphigus vulgaris typically reveals **acantholytic cells**, which are detached, rounded keratinocytes with basophilic cytoplasm. - The presence of acantholytic cells confirms the **loss of intercellular adhesion** within the epidermis, a hallmark of pemphigus.
Question 5: What diagnosis is suggested by the finding on the sole of this patient's foot?
- A. Chemical burn
- B. Pemphigus
- C. Plantar wart (Correct Answer)
- D. Radiation dermatitis
Explanation: ***Plantar wart (Verruca plantaris)*** - The image shows a **hyperkeratotic lesion with central black dots** on the sole of the foot, which is pathognomonic for a **plantar wart** - Plantar warts are caused by **human papillomavirus (HPV)** infection, most commonly types 1, 2, and 4 - The characteristic **black dots represent thrombosed capillaries**, not necrosis - Key diagnostic features include **interruption of skin lines** across the lesion and **tenderness on lateral compression** (pinch test) - They occur on **pressure-bearing areas** of the foot and can be solitary or multiple (mosaic warts) *Chemical burn* - Chemical burns present with **erythema, blistering, or ulceration** with more diffuse or irregular borders - History of **chemical exposure** would be present, and the lesion lacks the characteristic black dots seen in plantar warts - The pattern and location don't fit typical chemical injury *Pemphigus* - Pemphigus is an **autoimmune blistering disease** presenting with **flaccid bullae** that rupture easily - It primarily affects **mucous membranes and flexural areas**, rarely presenting as a solitary hyperkeratotic lesion on the sole - The clinical presentation is completely different from the hyperkeratotic lesion with black dots shown *Radiation dermatitis* - Radiation dermatitis occurs after **therapeutic or accidental radiation exposure** - Presents with **erythema, desquamation, hyperpigmentation, or fibrosis** in the radiation field - Would not present as a discrete hyperkeratotic lesion with black dots, and the sole of the foot is an unusual site for radiation therapy
Question 6: Which of the following drugs can lead to pemphigus?
- A. Carbamazepine
- B. Penicillamine (Correct Answer)
- C. Isoniazid
- D. Furosemide
Explanation: ***Penicillamine*** - **Penicillamine** is a well-known drug that can induce **pemphigus**, often through mechanisms involving alterations in **desmosome structure** or function. - The drug's sulfhydryl groups are thought to interfere with the integrity of **desmoglein proteins**, leading to blister formation. *Isoniazid* - **Isoniazid** is a first-line antituberculosis drug primarily associated with **hepatotoxicity** and **peripheral neuropathy**. - It is not typically implicated in the development of **pemphigus**. *Carbamazepine* - **Carbamazepine** is an anticonvulsant that can cause various cutaneous reactions, most notably **Stevens-Johnson syndrome (SJS)** and **toxic epidermal necrolysis (TEN)**. - While it can cause severe skin reactions, **pemphigus** is not a common side effect of carbamazepine. *Furosemide* - **Furosemide** is a loop diuretic that can cause **photosensitivity**, rashes, and rarely, severe skin reactions like **erythema multiforme**. - It is not recognized as a drug that induces **pemphigus**.
Question 7: Which histological finding is most specific for pemphigus vulgaris?
- A. Basement membrane thickening
- B. Granular IgA deposits
- C. Row of tombstones (Correct Answer)
- D. IgG linear deposits
Explanation: ***Row of tombstones*** - This characteristic histological finding in **pemphigus vulgaris** refers to the appearance of a single layer of basal cells still attached to the basement membrane, resembling a **row of tombstones**, after the detachment of suprabasal epidermal cells. - It signifies **acantholysis** (loss of cell-to-cell adhesion) occurring just above the basal layer. *Basement membrane thickening* - This finding is more characteristic of conditions like **lichen sclerosus** or some chronic inflammatory dermatoses, and is not specific for pemphigus vulgaris. - It does not directly reflect the underlying immune-mediated acantholysis seen in pemphigus. *Granular IgA deposits* - **Granular IgA deposits** along the dermal-epidermal junction are the hallmark of **dermatitis herpetiformis**. - Pemphigus vulgaris is characterized by IgG autoantibodies, not IgA, targeting desmogleins. *IgG linear deposits* - **Linear IgG deposits** along the dermal-epidermal junction are characteristic of **bullous pemphigoid**, not pemphigus vulgaris. - In pemphigus vulgaris, IgG deposits are typically found in a **chicken-wire pattern** intercellularly within the epidermis.
Question 8: A 50-year-old female presents with blisters and erosions on the skin and mucous membranes, most commonly inside the mouth. What is the most likely diagnosis?
- A. Pemphigus vulgaris (Correct Answer)
- B. Dermatitis herpetiformis
- C. Bullous pemphigoid
- D. Erythema multiforme
Explanation: ***Pemphigus vulgaris*** - This condition is characterized by **flaccid blisters** that easily rupture, leading to painful erosions, often starting in the **oral mucosa** (50-70% of cases). - It is an **autoimmune disease** with antibodies against **desmoglein 3 (mucous membranes) and desmoglein 1 (skin)**, causing **intraepidermal blistering**. - **Nikolsky sign positive** - lateral pressure causes sloughing of skin. *Dermatitis herpetiformis* - This presents with intensely **pruritic (itchy) grouped vesicles** on extensor surfaces (elbows, knees, buttocks), not flaccid blisters with oral involvement. - It is strongly associated with **celiac disease** and characterized by **IgA deposition in the dermal papillae**. *Bullous pemphigoid* - Presents with **tense blisters** on an erythematous base, typically in **elderly patients (>60 years)**. - **Oral mucosa usually spared** or involved late in the disease course. - Involves autoantibodies against **hemidesmosomal proteins (BP180 and BP230)**, leading to **subepidermal blistering**. *Erythema multiforme* - Characterized by **target lesions** and can involve mucous membranes, but typically presents acutely with symmetrical distribution. - Often triggered by **infections (HSV) or medications**, not an autoimmune blistering disease. - Lacks the chronic, progressive oral erosions typical of pemphigus vulgaris.
Question 9: Which of the following is NOT associated with erythema nodosum?
- A. Pemphigus vulgaris (Correct Answer)
- B. Tuberculosis
- C. Sarcoidosis
- D. Leprosy
Explanation: ***Pemphigus vulgaris*** - **Pemphigus vulgaris** is an **autoimmune blistering disease** that affects the skin and mucous membranes, characterized by flaccid bullae, not subcutaneous nodules. - Its pathophysiology involves **autoantibodies** against **desmoglein 1 and 3**, leading to **acantholysis**, which is distinct from the inflammatory changes seen in erythema nodosum. *Tuberculosis* - **Tuberculosis (TB)** is a common infectious cause of **erythema nodosum**, especially in regions with high TB prevalence. - The development of erythema nodosum in TB is often considered a **hypersensitivity reaction** to mycobacterial antigens. *Sarcoidosis* - **Sarcoidosis** is a systemic granulomatous disease, and **erythema nodosum** can be a prominent cutaneous manifestation, particularly in **Löfgren's syndrome**. - Its presence with **bilateral hilar lymphadenopathy** and **arthralgia** is highly suggestive of acute sarcoidosis. *Leprosy* - **Leprosy**, caused by *Mycobacterium leprae*, can be associated with **erythema nodosum leprosum (ENL)**, which is a type 2 lepra reaction. - **ENL** involves the formation of painful, tender, inflamed nodules that resemble erythema nodosum and is linked to elevated immune complex deposition.
Question 10: A skin biopsy shows suprabasilar acantholysis with 'row of tombstones' appearance. Which immunofluorescence pattern would confirm pemphigus vulgaris?
- A. Linear IgA deposits
- B. Fishnet pattern of IgG (Correct Answer)
- C. Granular IgG deposits
- D. Linear C3 deposits
Explanation: ***Fishnet pattern of IgG*** - Pemphigus vulgaris is characterized by **autoantibodies** (predominantly **IgG**) directed against **desmogleins 1 and 3**, components of desmosomes in the epidermis. - This binding leads to the **loss of cell adhesion** (acantholysis) and results in the characteristic **net-like or "fishnet" pattern** of IgG positivity on direct immunofluorescence (DIF), outlining keratinocyte cell surfaces. *Linear IgA deposits* - **Linear IgA bullous dermatosis** is characterized by the presence of continuous linear deposits of IgA along the **dermoepidermal junction** on direct immunofluorescence. - This condition is clinically and immunologically distinct from pemphigus vulgaris, which involves **intraepidermal deposition of IgG**. *Granular IgG deposits* - **Granular IgG deposits** at the dermoepidermal junction are typically seen in conditions like **lupus erythematosus**, particularly in the form of a **lupus band test**, rather than in blistering diseases like pemphigus. - Pemphigus involves **intercellular IgG deposition** within the epidermis, not granular deposits at the junction. *Linear C3 deposits* - **Linear C3 deposits** (often accompanied by IgG) along the **dermoepidermal junction** are characteristic of **bullous pemphigoid**, another autoimmune blistering disease. - Unlike pemphigus vulgaris, bullous pemphigoid involves autoantibodies targeting hemidesmosomes, leading to subepidermal blistering rather than intraepidermal acantholysis.
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