Blistering Diseases Practice Questions

Q: A 70-year-old man develops multiple pruritic skin lesions and bullae mostly in the axillae and around the medial aspects of his groin and thighs. Some lesions are present on his forearms and lower legs, with moderately painful oral lesions. Nikolsky sign is negative, and there is no eye involvement. Which of the following is the most likely diagnosis?

Bullous pemphigoid. ### Explanation **Bullous Pemphigoid (BP)** is the most likely diagnosis based on the clinical presentation. It is an autoimmune subepidermal blistering disease typically affecting the elderly (60–80 years). **Why Option C is Correct:** * **Clinical Presentation:** BP characteristically presents with large, **tense bullae** on an erythematous or eczematous base. The lesions are intensely **pruritic** and favor flexural areas like the axillae, groin, and inner thighs. * **Nikolsky Sign:** Since the split occurs at the dermo-epidermal junction (subepidermal), the epidermis is intact and firm; thus, the Nikolsky sign is **negative**. * **Mucosal Involvement:** Unlike Pemphigus, oral involvement is less common (seen in ~10–20% of cases) and usually less severe. **Why Other Options are Incorrect:** * **A. Dermatitis Herpetiformis:** Associated with Celiac disease; presents as extremely itchy, grouped (herpetiform) vesicles on extensor surfaces (elbows, knees). * **B. Pemphigus Vulgaris:** Characterized by **flaccid bullae** that rupture easily, a **positive Nikolsky sign**, and near-universal, severe oral involvement. It is an intraepidermal disorder. * **D. Cicatricial Pemphigoid (Mucous Membrane Pemphigoid):** Primarily affects mucous membranes (especially the eyes/conjunctiva, leading to scarring/symblepharon). The question explicitly states there is no eye involvement. **High-Yield Pearls for NEET-PG:** * **Target Antigens:** BP180 (Type XVII Collagen) and BP230. * **Histopathology:** Subepidermal blister with an inflammatory infiltrate rich in **eosinophils**. * **Direct Immunofluorescence (DIF):** Shows **linear** IgG and C3 deposits along the basement membrane zone ("Linear n-serrated pattern"). * **Treatment:** Potent topical corticosteroids (e.g., Clobetasol) are first-line for localized/moderate disease; systemic steroids for generalized cases.

Q: In pemphigus vulgaris, where are blisters typically located?

Intraepidermal. **Explanation:** **Pemphigus Vulgaris (PV)** is an autoimmune blistering disease characterized by the loss of cell-to-cell adhesion (acantholysis) within the epidermis. The correct answer is **Intraepidermal** because the pathology involves IgG autoantibodies directed against **Desmoglein 3** (and sometimes Desmoglein 1). These proteins are components of desmosomes, which hold keratinocytes together. When these bonds are disrupted, the keratinocytes separate, leading to the formation of a blister within the layers of the epidermis. Specifically, in PV, this cleavage occurs just above the basal layer, creating a "tombstone appearance" of the basal cells. **Analysis of Incorrect Options:** * **Subepidermal:** This is characteristic of **Bullous Pemphigoid** and Dermatitis Herpetiformis. In these conditions, the split occurs at the dermo-epidermal junction (basement membrane zone), leading to tense blisters, unlike the flaccid blisters of PV. * **Subdermal/Subfascial:** These layers are located deep within or below the dermis. Blistering diseases are primarily cutaneous (epidermal or dermal-epidermal junction) and do not typically involve these deep anatomical planes. **Clinical Pearls for NEET-PG:** * **Nikolsky Sign:** Positive (extension of the blister or denudation of skin with lateral pressure). * **Tzanck Smear:** Shows **Acantholytic cells** (Tzanck cells)—large, round keratinocytes with hyperchromatic nuclei. * **Immunofluorescence:** Direct Immunofluorescence (DIF) shows a characteristic **"fishnet" or "lace-like" pattern** of IgG/C3 deposits. * **Involvement:** Oral mucosa is almost always the initial site of involvement before skin lesions appear.

Q: A middle-aged man presented with multiple flaccid bullae and oral mucosal lesions. What is the most likely finding?

Fishnet IgG in epidermis. ### Explanation The clinical presentation of **middle-aged onset**, **flaccid bullae** (which rupture easily), and **oral mucosal involvement** is classic for **Pemphigus Vulgaris (PV)**. **Why Option B is Correct:** In Pemphigus Vulgaris, autoantibodies (IgG) are directed against **Desmoglein 3** (and sometimes Desmoglein 1), which are components of desmosomes. This leads to **acantholysis** (loss of cell-to-cell adhesion). On Direct Immunofluorescence (DIF), these IgG antibodies deposit in the intercellular spaces between keratinocytes, creating a characteristic **"fishnet" or "chicken-wire" pattern** throughout the epidermis. **Analysis of Incorrect Options:** * **Option A (Granular IgA in reticular dermis):** This is not a standard finding for any major blistering disease. Granular IgA in the **dermal papillae** is the hallmark of **Dermatitis Herpetiformis**. * **Option C (Linear IgG at the DEJ):** This is characteristic of **Bullous Pemphigoid**. Unlike PV, bullae in Pemphigoid are **tense**, and mucosal involvement is rare. * **Option D (Linear IgA in dermal papillae):** This is the diagnostic finding for **Linear IgA Bullous Dermatosis (LABD)**. **NEET-PG High-Yield Pearls:** 1. **Nikolsky Sign:** Positive in Pemphigus Vulgaris (due to intraepidermal cleavage) but negative in Bullous Pemphigoid (subepidermal cleavage). 2. **Tzanck Smear:** Shows **Acantholytic cells (Tzanck cells)**—large, round keratinocytes with hyperchromatic nuclei. 3. **Row of Tombstones:** Histopathology shows a basal layer of keratinocytes still attached to the basement membrane, but separated from the layers above. 4. **Antigen:** PV = Desmoglein 3 (Mucosa) + 1 (Skin); Pemphigus Foliaceus = Desmoglein 1 only (No mucosal lesions).

Q: What is the primary treatment for Dermatitis herpetiformis?

Gluten-free diet supplemented with minerals and vitamins. **Explanation:** **Dermatitis Herpetiformis (DH)** is a chronic, intensely pruritic autoimmune blistering disease characterized by subepidermal vesicles. It is considered the cutaneous manifestation of **Celiac Disease** (Gluten-sensitive enteropathy). **1. Why Option A is Correct:** The pathogenesis of DH involves IgA antibodies against **epidermal transglutaminase (eTG)**, which cross-react with **tissue transglutaminase (tTG)** found in the gut. Since the primary trigger is gluten ingestion, a **strict lifelong gluten-free diet (GFD)** is the definitive treatment. GFD not only resolves the skin lesions and intestinal atrophy over time but also reduces the long-term risk of intestinal lymphoma. Supplementation with vitamins and minerals is often necessary due to underlying malabsorption. **2. Why Incorrect Options are Wrong:** * **B. Carbamazepine:** This is an anticonvulsant/analgesic used for trigeminal neuralgia or epilepsy; it has no role in treating autoimmune bullous disorders. * **C. Acyclovir:** This is an antiviral used for Herpes Simplex. Despite the name "herpetiformis" (referring to the *grouped* appearance of vesicles), DH is not caused by a virus. * **D. Corticosteroids:** While used in Pemphigus or Bullous Pemphigoid, they are generally ineffective as primary therapy for DH. **NEET-PG High-Yield Pearls:** * **Drug of Choice (Symptomatic):** **Dapsone** is the DOC for rapid relief of itching and skin lesions (usually within 24-48 hours), but it does *not* treat the underlying enteropathy. * **Histopathology:** Subepidermal blister with **neutrophilic microabscesses** at the dermal papillary tips. * **Direct Immunofluorescence (DIF):** **Granular IgA deposits** in the dermal papillae (Gold Standard for diagnosis). * **Association:** Strongly linked with **HLA-DQ2 and HLA-DQ8**.

Q: Fish net pattern is seen in which of the following tests in pemphigus vulgaris?

Direct immunofluorescence. **Explanation:** **Pemphigus Vulgaris (PV)** is an autoimmune blistering disease characterized by the formation of intraepidermal blisters. The hallmark of its pathogenesis is the presence of IgG autoantibodies directed against **Desmoglein 3** (and sometimes Desmoglein 1), which are components of desmosomes responsible for cell-to-cell adhesion. * **Why Direct Immunofluorescence (DIF) is correct:** DIF is the gold standard for diagnosing PV. When a biopsy of perilesional skin is stained with fluorescein-tagged antibodies, it reveals **IgG and C3 deposits** in the intercellular spaces between keratinocytes. This creates a characteristic **"fish-net," "chicken-wire," or "honeycomb" pattern**, representing the distribution of desmosomes throughout the epidermis. **Analysis of Incorrect Options:** * **Tzanck Smear:** Used for rapid bedside diagnosis. It shows **Acantholytic cells (Tzanck cells)**—rounded, large keratinocytes with hyperchromatic nuclei—but does not show the fish-net pattern. * **Histopathology:** Shows **suprabasal acantholysis** (separation of cells) leading to a "row of tombstones" appearance of the basal layer. It confirms the level of the split but not the immunological pattern. * **FNAC:** This is generally not used for the diagnosis of vesiculobullous disorders. **High-Yield Clinical Pearls for NEET-PG:** * **Nikolsky Sign:** Positive (bulla spreads with lateral pressure). * **Bullae:** Flaccid and fragile; often presents first with oral ulcers. * **Indirect Immunofluorescence (IIF):** Uses patient serum to detect circulating antibodies; also shows a fish-net pattern. * **Salt-split skin test:** Used to differentiate PV (fluorescence on the epidermal roof) from Bullous Pemphigoid (fluorescence on the floor).

Q: Intercellular IgG deposition in the epidermis is seen in which of the following conditions?

Pemphigus. **Explanation:** The hallmark of the **Pemphigus group** (including Pemphigus Vulgaris and Pemphigus Foliaceus) is the presence of IgG autoantibodies directed against **desmogleins** (Dsg1 and Dsg3), which are components of desmosomes. On Direct Immunofluorescence (DIF), these antibodies bind to the cell surfaces of keratinocytes throughout the epidermis, resulting in a characteristic **"fishnet" or "chicken-wire" pattern** of intercellular IgG deposition. This leads to acantholysis (loss of cell-to-cell adhesion) and intraepidermal blister formation. **Analysis of Incorrect Options:** * **Subcorneal Pustular Dermatosis (Sneddon-Wilkinson disease):** This is a sterile neutrophilic dermatosis. DIF is typically **negative** for IgG/IgA deposition (though an IgA variant exists, it is not the classic intercellular IgG pattern). * **Bullous Pemphigoid:** This is a subepidermal blistering disease where IgG and C3 are deposited in a **linear pattern along the basement membrane zone (BMZ)**, targeting BP180 and BP230. * **Dermatitis Herpetiformis:** Associated with celiac disease, this condition shows **granular IgA deposits** specifically at the **tips of dermal papillae**. **Clinical Pearls for NEET-PG:** * **Pemphigus Vulgaris:** Most common type; involves oral mucosa; Nikolsky sign is positive; Tzanck smear shows **Acantholytic (Tzanck) cells**. * **Immunofluorescence Patterns:** * *Fishnet/Intercellular:* Pemphigus. * *Linear BMZ:* Bullous Pemphigoid, Epidermolysis Bullosa Acquisita. * *Granular Dermal Papillae:* Dermatitis Herpetiformis. * **Target Antigens:** P. Vulgaris (Dsg 3 > 1); P. Foliaceus (Dsg 1 only).

Q: Intercellular IgG deposition in the epidermis is seen in which of the following conditions?

Pemphigus. **Explanation:** The correct answer is **Pemphigus**. This group of autoimmune blistering diseases is characterized by the presence of IgG autoantibodies directed against **desmogleins** (transmembrane glycoproteins of desmosomes). On Direct Immunofluorescence (DIF), these antibodies appear as **intercellular IgG and C3 deposition** throughout the epidermis, creating a characteristic **"fishnet" or "chicken-wire" pattern**. This leads to loss of cell-to-cell adhesion, a process known as **acantholysis**. **Analysis of Incorrect Options:** * **Subcorneal Pustular Dermatosis (Sneddon-Wilkinson disease):** This is a sterile neutrophilic dermatosis. DIF is typically **negative** for immunoglobulin deposition. * **Bullous Pemphigoid:** This is a subepidermal blistering disease where IgG and C3 are deposited in a **linear pattern along the dermo-epidermal junction (basement membrane zone)**, targeting Hemidesmosomes (BP180/BP230). * **Dermatitis Herpetiformis:** Associated with celiac disease, this condition shows **granular IgA deposition** at the **tips of dermal papillae**. **High-Yield Clinical Pearls for NEET-PG:** * **Pemphigus Vulgaris:** Most common type; involves Desmoglein 3 (±1); presents with oral ulcers and a **positive Nikolsky sign**. * **Tzanck Smear:** Look for **Acantholytic cells** (Tzanck cells)—large, round keratinocytes with hyperchromatic nuclei. * **Histopathology:** Pemphigus vulgaris shows "row of tombstones" appearance at the basal layer. * **Treatment:** Systemic corticosteroids are the mainstay; Rituximab is now a first-line biological option.

Q: Tense itching bulla is seen in?

Bullous pemphigoid. **Explanation:** The hallmark of **Bullous Pemphigoid (BP)** is the presence of **tense, large bullae** occurring on an erythematous or normal skin base, typically accompanied by **intense pruritus (itching)**. 1. **Why Bullous Pemphigoid is correct:** BP is an autoimmune subepidermal blistering disease caused by IgG antibodies against hemidesmosomal proteins (**BP180 and BP230**). Because the split occurs deep at the dermo-epidermal junction, the "roof" of the blister consists of the entire epidermis. This makes the blister structurally strong and **tense**, meaning it does not rupture easily (Negative Nikolsky sign). 2. **Why other options are incorrect:** * **Dermatitis Herpetiformis:** Characterized by extremely itchy, small, grouped vesicles (herpetiform) on extensor surfaces. While it is itchy, it presents as **vesicles**, not large tense bullae. * **Pemphigus Vulgaris:** An intraepidermal disease (targeting Desmoglein 3). Because the split is superficial, the blisters are **flaccid** and rupture easily, leaving painful erosions. It is typically painful, not itchy. * **Erythema Multiforme:** Characterized by classic **"target" or "iris" lesions**. While bullae can occur in severe cases, they are not the primary diagnostic feature, and the clinical context (post-infections like HSV) differs. **High-Yield Clinical Pearls for NEET-PG:** * **Nikolsky Sign:** Negative in BP; Positive in Pemphigus Vulgaris. * **Direct Immunofluorescence (DIF):** Shows **linear** IgG and C3 deposits along the basement membrane zone. * **Histopathology:** Subepidermal blister with an inflammatory infiltrate rich in **eosinophils**. * **Demographics:** Typically affects the elderly (>60 years).

Q: Which of the following conditions is characterized by epidermal bullae?

Bullous impetigo. **Explanation:** The classification of blistering diseases is based on the anatomical level of cleavage. Blisters are categorized as **Intraepidermal** (within the epidermis) or **Subepidermal** (below the basement membrane zone). **Why Bullous Impetigo is Correct:** Bullous impetigo is caused by *Staphylococcus aureus* (Phage group II). The bacteria produce **Exfoliative Toxin A**, which specifically targets and cleaves **Desmoglein 1** in the *stratum granulosum*. This results in a very superficial, intraepidermal split, leading to flaccid bullae that rupture easily, leaving behind a "collarette of scale." **Why the other options are incorrect:** * **Bullous Pemphigoid:** This is a **subepidermal** blistering disease. Autoantibodies (anti-BP180 and anti-BP230) target the hemidesmosomes, causing the entire epidermis to lift off the dermis, resulting in tense bullae. * **Porphyria Cutanea Tarda (PCT):** This is a metabolic disorder of heme synthesis characterized by **subepidermal** blisters on sun-exposed areas (dorsum of hands). It is associated with cell-poor subepidermal cleavage and "caterpillar bodies." * **Dermatitis Herpetiformis:** This is an IgA-mediated autoimmune disease associated with Celiac disease. It is characterized by **subepidermal** vesicles formed due to neutrophilic microabscesses at the dermal papillary tips. **High-Yield Clinical Pearls for NEET-PG:** * **Intraepidermal Blisters:** Pemphigus vulgaris (suprabasal), Pemphigus foliaceus (subcorneal), and Bullous impetigo (subcorneal). * **Subepidermal Blisters:** Bullous pemphigoid, Cicatricial pemphigoid, Dermatitis herpetiformis, and Epidermolysis bullosa acquisita. * **Nikolsky Sign:** Usually positive in intraepidermal blisters (e.g., Pemphigus) and negative in subepidermal blisters (e.g., Bullous pemphigoid).

Q: A 30-year-old pregnant woman presents with painful oral ulcers. Physical examination demonstrates widespread erosions of her mucous membranes and a friable mucosa, but no well-defined aphthous ulcers. Biopsy of perilesional mucosa demonstrates acantholysis, and direct immunofluorescence demonstrates an intraepidermal band of IgG and C3. Which of the following is the most likely diagnosis?

Pemphigus vulgaris. **Explanation:** The clinical presentation and immunofluorescence findings are classic for **Pemphigus Vulgaris (PV)**. PV is an autoimmune blistering disease caused by IgG antibodies against **Desmoglein 3** (primarily mucosal) and **Desmoglein 1** (skin). 1. **Why Pemphigus Vulgaris is correct:** * **Clinical:** It typically begins with painful oral ulcers and erosions. The "friable mucosa" indicates the fragile nature of the epithelium. * **Histopathology:** The hallmark is **acantholysis** (loss of intercellular connections), leading to intraepidermal blister formation. * **Direct Immunofluorescence (DIF):** Shows a characteristic **"fishnet" or "lace-like" pattern** of IgG and C3 deposits in the intercellular spaces of the epidermis (intraepidermal band). 2. **Why other options are incorrect:** * **Bullous pemphigoid:** Characterized by tense bullae and subepidermal blisters. DIF shows a **linear** band along the basement membrane zone (BMZ), not intraepidermal. Oral involvement is rare. * **Dermatitis herpetiformis:** Associated with celiac disease; presents with extremely pruritic vesicles on extensors. DIF shows **granular IgA** deposits in dermal papillae. * **Herpes simplex I:** While it causes oral ulcers, it would show multinucleated giant cells on Tzanck smear and would not demonstrate a continuous intraepidermal IgG band on DIF. **NEET-PG High-Yield Pearls:** * **Nikolsky Sign:** Positive in Pemphigus Vulgaris (extension of blister with lateral pressure). * **Tzanck Smear:** Shows **Acantholytic cells (Tzanck cells)**—rounded keratinocytes with hyperchromatic nuclei. * **Row of Tombstones:** Appearance of the basal layer remaining attached to the basement membrane in PV. * **Pregnancy:** PV can occur in pregnancy and may lead to neonatal pemphigus due to transplacental transfer of IgG.

Question 1

A 70-year-old man develops multiple pruritic skin lesions and bullae mostly in the axillae and around the medial aspects of his groin and thighs. Some lesions are present on his forearms and lower legs, with moderately painful oral lesions. Nikolsky sign is negative, and there is no eye involvement. Which of the following is the most likely diagnosis?

Accepted Answer

Bullous pemphigoid

Answer

Dermatitis herpetiformis

Answer

Pemphigus vulgaris

Answer

Cicatricial pemphigoid

Question 2

In pemphigus vulgaris, where are blisters typically located?

Accepted Answer

Intraepidermal

Answer

Subepidermal

Answer

Subdermal

Answer

Subfascial

Question 3

A middle-aged man presented with multiple flaccid bullae and oral mucosal lesions. What is the most likely finding?

Accepted Answer

Fishnet IgG in epidermis

Answer

Granular IgA in reticular dermis

Answer

Linear IgG at the dermoepidermal junction

Answer

Linear IgA in dermal papillae

Question 4

What is the primary treatment for Dermatitis herpetiformis?

Accepted Answer

Gluten-free diet supplemented with minerals and vitamins

Answer

Carbamazepine

Answer

Acyclovir

Answer

Corticosteroids

Question 5

Fish net pattern is seen in which of the following tests in pemphigus vulgaris?

Accepted Answer

Direct immunofluorescence

Answer

Tzanck smear

Answer

Fine needle aspiration cytology

Answer

Histopathology

Question 6

Intercellular IgG deposition in the epidermis is seen in which of the following conditions?

Accepted Answer

Pemphigus

Answer

Subcorneal pustular dermatosis

Answer

Bullous pemphigoid

Answer

Dermatitis herpetiformis

Question 7

Intercellular IgG deposition in the epidermis is seen in which of the following conditions?

Accepted Answer

Pemphigus

Answer

Subcorneal pustular dermatosis

Answer

Bullous pemphigoid

Answer

Dermatitis herpetiformis

Question 8

Tense itching bulla is seen in?

Accepted Answer

Bullous pemphigoid

Answer

Dermatitis herpetiformis

Answer

Pemphigus vulgaris

Answer

Erythema multiforme

Question 9

Which of the following conditions is characterized by epidermal bullae?

Accepted Answer

Bullous impetigo

Answer

Bullous pemphigoid

Answer

Porphyria cutanea tarda

Answer

Dermatitis herpetiformis

Question 10

A 30-year-old pregnant woman presents with painful oral ulcers. Physical examination demonstrates widespread erosions of her mucous membranes and a friable mucosa, but no well-defined aphthous ulcers. Biopsy of perilesional mucosa demonstrates acantholysis, and direct immunofluorescence demonstrates an intraepidermal band of IgG and C3. Which of the following is the most likely diagnosis?

Accepted Answer

Pemphigus vulgaris

Answer

Bullous pemphigoid

Answer

Dermatitis herpetiformis

Answer

Herpes simplex I

Blistering Diseases — MCQs

Blistering Diseases — MCQs

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