Blistering Diseases Practice Questions

Q: Pemphigus vulgaris is caused due to which type of hypersensitivity reaction?

Type II. **Explanation:** **Pemphigus vulgaris (PV)** is a classic example of a **Type II Hypersensitivity reaction**. In this condition, the body produces IgG autoantibodies (specifically against **Desmoglein 3** and **Desmoglein 1**) that target antigens located on the surface of keratinocytes. This is a "cytotoxic" or "antibody-mediated" reaction where the binding of antibodies leads to the loss of cell-to-cell adhesion (acantholysis), resulting in the formation of intraepidermal blisters. **Why other options are incorrect:** * **Type I (Immediate):** Mediated by IgE and mast cell degranulation (e.g., Anaphylaxis, Urticaria). PV involves IgG and a chronic autoimmune process. * **Type III (Immune-complex):** Caused by the deposition of antigen-antibody complexes in tissues (e.g., SLE, Post-streptococcal glomerulonephritis). In PV, the antibody binds directly to the fixed tissue antigen. * **Type IV (Delayed):** T-cell mediated reaction (e.g., Contact dermatitis, Tuberculin test). PV is primarily driven by humoral (antibody) immunity. **High-Yield Clinical Pearls for NEET-PG:** * **Target Antigen:** Desmoglein 3 (mucosal-dominant) and Desmoglein 1 (mucocutaneous). * **Immunofluorescence:** Direct Immunofluorescence (DIF) shows a characteristic **"Fish-net"** or "Lace-like" pattern of IgG/C3 deposition. * **Histopathology:** Shows **"Row of Tombstones"** appearance (basal layer remains attached to the basement membrane). * **Clinical Signs:** Positive **Nikolsky sign** and Bulla spread sign (Asboe-Hansen sign). * **Tzanck Smear:** Shows **Acantholytic cells** (Tzanck cells/Tzanck corpuscles).

Q: Dermatitis herpetiformis is associated with all of the following except?

Ulcerative colitis. **Explanation:** Dermatitis Herpetiformis (DH) is a chronic, intensely pruritic autoimmune blistering disease characterized by subepidermal vesicles. It is considered the cutaneous manifestation of **Gluten-Sensitive Enteropathy (Celiac Disease)**. **Why Ulcerative Colitis (Option D) is the correct answer:** While DH is strongly linked to various autoimmune conditions (like Type 1 Diabetes and Autoimmune Thyroiditis), it is **not** typically associated with Ulcerative Colitis. Ulcerative colitis is more frequently associated with other dermatological conditions like *Pyoderma Gangrenosum* and *Erythema Nodosum*. **Analysis of other options:** * **Gluten-sensitive enteropathy (Option A):** Nearly 90-100% of DH patients have underlying Celiac disease (though it may be asymptomatic/subclinical). Both share the same HLA associations (**HLA-DQ2 and HLA-DQ32**). * **Enteral lymphoma (Option B):** Due to the chronic inflammation of the gut in gluten-sensitive enteropathy, patients with DH have an increased risk of developing **Enteropathy-associated T-cell lymphoma (EATL)**. A strict gluten-free diet is protective against this. * **Atrophic gastritis (Option C):** DH is associated with various gastric abnormalities, including achlorhydria and atrophic gastritis, likely due to the shared autoimmune milieu. **High-Yield Clinical Pearls for NEET-PG:** * **Hallmark Pathology:** Granular IgA deposits in the dermal papillae (tips). * **Site of Predilection:** Extensor surfaces (elbows, knees, buttocks). * **Biopsy Finding:** Subepidermal blister with **neutrophilic microabscesses** at the papillary tips. * **Drug of Choice:** **Dapsone** (provides rapid symptomatic relief but does not treat the underlying enteropathy). * **Dietary Management:** Strict lifelong Gluten-Free Diet (GFD).

Q: The "dilapidated brick wall" appearance is classically seen in the histopathology of which of the following conditions?

Hailey Hailey disease. **Explanation:** The **"dilapidated brick wall"** appearance is the pathognomonic histopathological description for **Hailey-Hailey disease** (Familial Benign Pemphigus). This appearance is caused by **extensive acantholysis** (loss of intercellular connections) affecting all layers of the epidermis. Unlike other conditions, the keratinocytes do not completely separate; they remain loosely attached by a few preserved desmosomes, resembling a crumbling or "dilapidated" brick wall. **Why the other options are incorrect:** * **Pemphigus vulgaris:** While it also shows acantholysis, it is typically **suprabasal**, leading to a "tombstone appearance" of the basal layer. It does not involve the full-thickness "crumbling" seen in Hailey-Hailey. * **Darier’s disease:** Characterized by **focal** acantholysis and prominent **dyskeratosis** (corps ronds and grains). The acantholysis is less extensive than in Hailey-Hailey. * **Bullous pemphigoid:** This is a **subepidermal** blistering disease. There is no acantholysis; instead, there is a complete detachment of the epidermis from the dermis at the dermo-epidermal junction. **High-Yield Clinical Pearls for NEET-PG:** * **Genetics:** Hailey-Hailey is caused by a mutation in the **ATP2C1 gene** (encoding a Ca2+ ATPase pump in the Golgi apparatus). * **Clinical Presentation:** Recurrent vesicles and erosions in **intertriginous areas** (axilla, groin, neck). * **Differentiation:** Unlike Pemphigus, Hailey-Hailey is **not autoimmune** (Immunofluorescence is negative). * **Darier’s vs. Hailey-Hailey:** Darier’s has more dyskeratosis and less acantholysis; Hailey-Hailey has more acantholysis and minimal dyskeratosis.

Q: A patient with gluten-sensitive enteropathy has a lifelong history of periodic crops of intensely pruritic, grouped, papular or vesicular lesions on the elbows, knees, sacrum, and shoulders. The patient routinely scratches the top off the vesicles due to intense pruritus, which relieves the itching. What is the most likely diagnosis?

Dermatitis herpetiformis. ### Explanation **Correct Answer: B. Dermatitis herpetiformis (DH)** **Why it is correct:** Dermatitis herpetiformis is a chronic, autoimmune blistering disease strongly associated with **Gluten-Sensitive Enteropathy (Celiac Disease)**. The clinical hallmark is **intense pruritus** (itching) and a **symmetrical distribution** of grouped (herpetiform) vesicles, papules, or urticarial plaques on extensor surfaces like the elbows, knees, sacrum, and shoulders. Because the itching is so severe, patients often scratch the vesicles immediately, leaving only crusts or erosions (excoriations) for the clinician to see. **Why the other options are wrong:** * **Bullous Pemphigoid:** Typically affects the elderly and presents with large, tense bullae on an erythematous base, usually on the trunk and flexural areas. It is not associated with gluten sensitivity. * **Herpes Simplex I:** While it presents with grouped vesicles, it is usually localized (e.g., orolabial), acute, and not associated with enteropathy or a lifelong extensor distribution. * **Pemphigus Vulgaris:** Characterized by fragile, flaccid bullae that rupture easily to form painful (not primarily pruritic) erosions. It involves mucous membranes and shows a positive Nikolsky sign. **High-Yield Clinical Pearls for NEET-PG:** * **Pathogenesis:** IgA antibodies against **epidermal transglutaminase (eTG)**; cross-reactivity with tissue transglutaminase (tTG) in the gut. * **Histopathology:** Subepidermal blister with **neutrophilic microabscesses** at the tips of dermal papillae. * **Direct Immunofluorescence (DIF):** **Granular IgA deposits** in the dermal papillae (Gold Standard for diagnosis). * **Treatment of Choice:** **Dapsone** (provides rapid relief of itch) and a **Gluten-free diet** (long-term management).

Q: Positive Nikolsky's sign is a feature of?

Pemphigus. **Explanation:** **Nikolsky’s Sign** is a clinical dermatological sign where the top layer of the skin (epidermis) slips away from the lower layers when slight tangential pressure is applied. **1. Why Pemphigus is Correct:** Pemphigus (specifically Pemphigus Vulgaris) is characterized by **acantholysis**—the loss of intercellular connections (desmosomes) between keratinocytes due to IgG autoantibodies against Desmoglein 1 and 3. Because the adhesion within the epidermis is compromised, the cells easily separate, leading to a **positive Nikolsky sign** and the formation of thin-walled, flaccid bullae. **2. Why Other Options are Incorrect:** * **Pemphigoid (Bullous Pemphigoid):** This is a **subepidermal** blistering disease where the split occurs at the dermo-epidermal junction (due to antibodies against BP180/230). The roof of the blister is the entire epidermis, making it thick and tense; thus, Nikolsky’s sign is **negative**. * **Dermatitis Herpetiformis:** This is an intensely pruritic autoimmune disease associated with Celiac disease. It involves IgA deposits at the dermal papillary tips, resulting in subepidermal vesicles. Nikolsky’s sign is **negative**. * **Rubella:** This is a viral exanthematous fever characterized by a maculopapular rash, not blistering. It does not involve loss of epidermal adhesion. **High-Yield Clinical Pearls for NEET-PG:** * **Asboe-Hansen Sign (Indirect Nikolsky):** Extension of a blister into adjacent unaffected skin when pressure is applied to the top of the bulla. Also positive in Pemphigus. * **Other Nikolsky Positive Conditions:** Stevens-Johnson Syndrome (SJS), Toxic Epidermal Necrolysis (TEN), and Staphylococcal Scalded Skin Syndrome (SSSS). * **Tzanck Smear in Pemphigus:** Shows "Acantholytic cells" (Tzanck cells)—large, round keratinocytes with hyperchromatic nuclei.

Q: All of the following are features of an intraepidermal bullae, EXCEPT:

Have thick roof and less likely to rupture. In dermatology, blistering diseases are classified based on the level of cleavage within the skin. **Intraepidermal bullae** (e.g., Pemphigus vulgaris) occur within the epidermis, whereas **subepidermal bullae** (e.g., Bullous pemphigoid) occur below the basement membrane zone. ### Why Option C is the Correct Answer (The Exception) Intraepidermal bullae have a **thin, fragile roof** consisting only of a few layers of the epidermis. Because the roof is thin, these blisters are under low tension, making them **highly prone to rupture**. Conversely, subepidermal bullae have the entire epidermis as their roof, making them tense, thick-walled, and less likely to rupture. ### Analysis of Other Options * **A. Flaccidity:** Because the cleavage is superficial and the roof is thin, intraepidermal blisters lack structural integrity and appear "flaccid" or saggy. * **B. Contains serous/turbid fluid:** These blisters initially contain clear serous fluid, which may become turbid due to secondary infection or inflammatory cells. * **D. Leaves hyperpigmentation on healing:** Intraepidermal blisters typically heal without scarring (as the dermis is intact) but frequently leave behind **Post-Inflammatory Hyperpigmentation (PIH)**. ### NEET-PG High-Yield Pearls * **Nikolsky Sign:** Positive in intraepidermal blisters (Pemphigus) but negative in subepidermal blisters (Pemphigoid). * **Bullae Spread Sign (Asboe-Hansen):** Positive in intraepidermal blisters; peripheral extension of the blister upon applying pressure. * **Tzanck Smear:** Used for intraepidermal blisters to look for **Acantholytic cells** (Tzanck cells). * **Healing:** Intraepidermal = No scarring; Subepidermal = May show scarring and milia formation.

Q: Defects in which of the following does NOT cause blistering?

Filaggrin. **Explanation:** Blistering (bullous) diseases occur due to defects in structural proteins that maintain cell-to-cell adhesion (desmosomes) or cell-to-basement membrane adhesion (hemidesmosomes). **Why Filaggrin is the Correct Answer:** **Filaggrin** (Filament Aggregating Protein) is not a structural adhesion molecule. Its primary role is to aggregate keratin filaments into tight bundles to form the cornified envelope and maintain the skin barrier. Mutations in the *FLG* gene lead to **Ichthyosis vulgaris** and **Atopic dermatitis**, which are characterized by dry, scaly skin and barrier dysfunction, **not** blistering. **Why the other options are incorrect:** * **Collagen VII and Pectin:** Collagen VII forms anchoring fibrils; its defect causes **Dystrophic Epidermolysis Bullosa (DEB)**. Plectin (often grouped with pectin in clinical shorthand) is a plaque protein in hemidesmosomes; its defect causes **EB with Muscular Dystrophy**. * **Laminin:** Laminin-332 is a key component of the lamina lucida. Defects lead to **Junctional Epidermolysis Bullosa (JEB)**, a severe blistering condition. * **Keratin:** Keratins 5 and 14 provide structural integrity to basal keratinocytes. Mutations cause **Epidermolysis Bullosa Simplex (EBS)**, where cells rupture easily, leading to intraepidermal blisters. **NEET-PG High-Yield Pearls:** * **EBS:** Defect in Keratin 5, 14 (Basal layer). * **JEB:** Defect in Laminin-332 (Lamina lucida). * **DEB:** Defect in Collagen VII (Anchoring fibrils). * **Pemphigus Vulgaris:** IgG against Desmoglein 3 (and 1). * **Bullous Pemphigoid:** IgG against BP180 (Collagen XVII) and BP230.

Q: What is the proved association of celiac sprue?

Dermatitis herpetiformis. **Explanation:** **Dermatitis Herpetiformis (DH)** is the correct answer because it is considered the cutaneous manifestation of gluten-sensitive enteropathy (**Celiac Sprue**). Both conditions share the same genetic predisposition (HLA-DQ2 and HLA-DQ8) and the same underlying pathophysiology: an autoimmune response to **tissue transglutaminase (tTG)**. In the skin, antibodies cross-react with **epidermal transglutaminase (eTG/TG3)**, leading to IgA deposition. * **Why DH is correct:** Nearly 90% of patients with DH have evidence of gluten-sensitive enteropathy on intestinal biopsy, although many remain asymptomatic. Both conditions improve significantly with a **gluten-free diet**. * **Why others are incorrect:** * **Scleroderma:** An autoimmune connective tissue disorder characterized by fibrosis; it has no direct association with gluten sensitivity. * **Pemphigus:** An intraepidermal blistering disease caused by antibodies against desmogleins; it is not linked to Celiac disease. * **Pomphoid (Bullous Pemphigoid):** A subepidermal blistering disease caused by antibodies against BP180/230; it is typically seen in the elderly and is not associated with malabsorption syndromes. **High-Yield Clinical Pearls for NEET-PG:** 1. **Clinical Presentation:** Intensely pruritic, grouped vesicles (herpetiform) typically on extensor surfaces (elbows, knees, buttocks). 2. **Histopathology:** Subepidermal blister with **neutrophilic microabscesses** at the dermal papillary tips. 3. **Direct Immunofluorescence (DIF):** Gold standard diagnostic test showing **granular IgA deposits** at the dermal papillae. 4. **Treatment of Choice:** **Dapsone** (provides rapid symptomatic relief) and a lifelong **Gluten-free diet** (reduces the risk of GI lymphoma).

Question 1

Pemphigus vulgaris is caused due to which type of hypersensitivity reaction?

Accepted Answer

Type II

Answer

Type I

Answer

Type III

Answer

Type IV

Question 2

A 85-year-old woman presents with blisters on her thigh and trunk that come on and off. Nikolsky sign is negative. What is the most likely cause?

Accepted Answer

Pemphigoid

Answer

Pemphigus vulgaris

Answer

Lichen planus

Answer

Dermatitis herpetiformis

Question 3

Dermatitis herpetiformis is associated with all of the following except?

Accepted Answer

Ulcerative colitis

Answer

Gluten sensitive enteropathy

Answer

Enteral lymphoma

Answer

Atrophic gastritis

Question 4

The "dilapidated brick wall" appearance is classically seen in the histopathology of which of the following conditions?

Accepted Answer

Hailey Hailey disease

Answer

Pemphigus vulgaris

Answer

Darier's disease

Answer

Bullous pemphigoid

Question 5

A patient with gluten-sensitive enteropathy has a lifelong history of periodic crops of intensely pruritic, grouped, papular or vesicular lesions on the elbows, knees, sacrum, and shoulders. The patient routinely scratches the top off the vesicles due to intense pruritus, which relieves the itching. What is the most likely diagnosis?

Accepted Answer

Dermatitis herpetiformis

Answer

Bullous pemphigoid

Answer

Herpes simplex I

Answer

Pemphigus vulgaris

Question 6

Positive Nikolsky's sign is a feature of?

Accepted Answer

Pemphigus

Answer

Pemphigoid

Answer

Dermatitis herpetiformis

Answer

Rubella

Question 7

All of the following are features of an intraepidermal bullae, EXCEPT:

Accepted Answer

Have thick roof and less likely to rupture

Answer

Flaccidity

Answer

Contains serous/turbid fluid

Answer

Leaves hyperpigmentation on healing

Question 8

Defects in which of the following does NOT cause blistering?

Accepted Answer

Filaggrin

Answer

Collagen VII and pectin

Answer

Laminin

Answer

Keratin

Question 9

What is the proved association of celiac sprue?

Accepted Answer

Dermatitis herpetiformis

Answer

Scleroderma

Answer

Pemphigus

Answer

Pomphoid

Question 10

A female presented with skin lesions all over the body which shows a positive 'bulla spread sign'. What is this characteristic of?

Accepted Answer

Pemphigus vulgaris

Answer

Herpes gestationis

Answer

Bullous pemphigoid

Answer

Herpes simplex

Blistering Diseases — MCQs

Blistering Diseases — MCQs

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