Blistering Diseases Practice Questions

Q: Familial benign pemphigus is also known as:

Hailey-hailey disease.. **Explanation:** **Hailey-Hailey Disease (HHD)**, also known as **Familial Benign Pemphigus**, is an autosomal dominant genodermatosis. The underlying defect is a mutation in the **ATP2C1 gene** on chromosome 3q21, which encodes the **SPCA1 calcium pump** in the Golgi apparatus. This leads to impaired intracellular calcium signaling, resulting in a loss of adhesion between keratinocytes (**acantholysis**). Clinically, it presents as recurrent vesicles and erosions, typically in intertriginous areas (axilla, groin, and neck), often described as having a "wet tissue paper" appearance. **Analysis of Incorrect Options:** * **A. Brazilian Pemphigus:** Also known as **Fogo Selvagem**, this is an endemic form of Pemphigus Foliaceus caused by IgG4 antibodies against Desmoglein-1, often linked to the bite of the *Simulium nigrimanum* fly. * **B. Cicatricial Pemphigoid:** Also known as **Mucous Membrane Pemphigoid**, this is a chronic autoimmune subepidermal blistering disease that primarily affects mucous membranes and leads to scarring (cicatrix). **High-Yield Clinical Pearls for NEET-PG:** * **Histopathology:** Shows widespread acantholysis affecting all layers of the epidermis, giving the classic **"Dilapidated Brick Wall"** appearance. * **Immunofluorescence:** Unlike true Pemphigus, Direct Immunofluorescence (DIF) is **negative** in Hailey-Hailey disease because it is a genetic defect, not an autoimmune one. * **Differential Diagnosis:** Must be distinguished from **Darier Disease** (ATP2A2 mutation), which shows "corps ronds" and "grains" on histology, and **Pemphigus Vegetans**, which involves the flexures but is autoimmune.

Q: Which of the following is true about erythema multiforme?

Target lesions are seen. **Erythema Multiforme (EM)** is an acute, self-limiting, immune-mediated hypersensitivity reaction. It is characterized by the sudden onset of symmetric cutaneous lesions. ### **Explanation of Options:** * **Option B (Correct):** The hallmark of EM is the **target (iris) lesion**. A classic target lesion consists of three concentric zones: a central dusky/blistering area, a surrounding pale edematous ring, and a peripheral erythematous halo. These are typically found on the extremities (acral distribution). * **Option A (Incorrect):** The most common trigger for EM is **Herpes Simplex Virus (HSV)**, specifically HSV-1. While drugs (like NSAIDs or sulfonamides) can cause it, viral infections account for the majority of cases. HIV is not a primary trigger. * **Option C (Incorrect):** Unlike Stevens-Johnson Syndrome (SJS), EM usually presents with **minimal or no prodromal symptoms**. If present, they are mild (low-grade fever or malaise). * **Option D (Incorrect):** Mucosal involvement occurs in **EM Major**, but it is generally less frequent and less severe than in SJS/TEN. In **EM Minor**, mucosal involvement is typically absent. ### **High-Yield Clinical Pearls for NEET-PG:** 1. **Classification:** * **EM Minor:** No mucosal involvement, minimal systemic symptoms. * **EM Major:** Involvement of at least one mucosa (usually oral). 2. **Pathogenesis:** It is a **Type IV (Cell-mediated) hypersensitivity** reaction. 3. **Histology:** Shows "satellite cell necrosis" (individual keratinocyte death) and subepidermal edema. 4. **Key Differentiator:** EM is now considered a distinct entity from SJS/TEN. EM is usually post-infectious (HSV), whereas SJS/TEN is almost always drug-induced. 5. **Distribution:** Centripetal spread (starts at extremities and moves towards the trunk).

Q: Acantholytic cells are typically found in the blister cavity in which of the following conditions?

Pemphigus. ### Explanation **Correct Answer: A. Pemphigus** **1. Why Pemphigus is correct:** The hallmark of Pemphigus (specifically Pemphigus Vulgaris) is **acantholysis**, which refers to the loss of intercellular connections (desmosomes) between keratinocytes. This is caused by IgG autoantibodies against **Desmoglein 1 and 3**. When these connections break, the keratinocytes become rounded, detached, and float within the blister cavity. These detached cells are known as **Tzanck cells** or acantholytic cells. Because the split occurs within the epidermis (intraepidermal), these cells are easily visible in a Tzanck smear. **2. Why the other options are incorrect:** * **Bullous Pemphigoid:** This is a **subepidermal** blistering disease where autoantibodies (anti-BP180/230) target the hemidesmosomes at the dermo-epidermal junction. Since the entire epidermis lifts off the dermis intact, there is no intraepidermal cell detachment (no acantholysis). * **Epidermolysis Bullosa:** This represents a group of genetic mechanobullous disorders caused by structural protein defects (like Keratin 5/14 or Collagen VII). The split occurs due to structural fragility, not immunologic acantholysis. * **Dermatitis Herpetiformis:** This is characterized by subepidermal neutrophils forming **microabscesses at the dermal papillary tips**. It is associated with Celiac disease and IgA deposits, but does not involve acantholysis. **3. NEET-PG High-Yield Pearls:** * **Tzanck Smear:** Used for rapid diagnosis. Look for "Acantholytic cells" in Pemphigus and "Multinucleated giant cells" in Herpes Simplex/Varicella. * **Nikolsky Sign:** Positive in Pemphigus (due to acantholysis) but negative in Bullous Pemphigoid. * **Row of Tombstones:** Histopathological appearance of the basal layer in Pemphigus Vulgaris. * **Immunofluorescence:** Pemphigus shows a **"Fish-net"** or reticular pattern, while Bullous Pemphigoid shows a **linear** pattern along the basement membrane.

Q: Which of the following is mainly a non-inflammatory blistering disorder?

Epidermolysis bullosa. **Explanation:** The core distinction in blistering diseases lies between **inflammatory** (immunological) and **non-inflammatory** (mechanobullous) etiologies. **Why Epidermolysis Bullosa (EB) is correct:** Epidermolysis bullosa is a group of genetic, non-inflammatory disorders characterized by structural defects in the proteins that anchor the epidermis to the dermis (e.g., Keratin 5/14, Type VII collagen). Because the primary pathology is a **mechanical/structural weakness** rather than an immune-mediated attack, there is a lack of significant inflammatory infiltrate. Blisters typically occur in response to minor trauma or friction (mechanobullous). **Why the other options are incorrect:** * **Pemphigus (B) and Bullous Pemphigoid (D):** These are **autoimmune** blistering diseases. They involve an active inflammatory process where autoantibodies (IgG) target desmosomal or hemidesmosomal proteins, triggering an inflammatory cascade and recruitment of inflammatory cells. * **Dermatitis Herpetiformis (A):** This is a highly inflammatory condition associated with Celiac disease. It is characterized by IgA deposits at the dermal papillae, leading to the recruitment of **neutrophils** and the formation of microabscesses. **High-Yield Clinical Pearls for NEET-PG:** 1. **Nikolsky Sign:** Positive in Pemphigus Vulgaris (intraepidermal); Negative in Bullous Pemphigoid (subepidermal). 2. **EB Simplex:** Most common type; defect in Keratin 5 and 14. 3. **Dystrophic EB:** Defect in Type VII collagen (anchoring fibrils); leads to scarring and "mitten-hand" deformities. 4. **Direct Immunofluorescence (DIF):** Essential for diagnosing inflammatory blisters (Options A, B, D) but typically negative/non-diagnostic for EB.

Q: Which type of pemphigus is also known as Brazilian wild fire?

Pemphigus foliaceus. **Explanation:** The correct answer is **Pemphigus foliaceus (Option A)**. Specifically, the endemic form of Pemphigus foliaceus is known as **Fogo Selvagem** (Portuguese for "Wild Fire"). It is primarily found in rural Brazil and is thought to be triggered by environmental factors, possibly linked to blackfly bites (*Simulium nigrimanum*). **Why Option A is correct:** Pemphigus foliaceus is a superficial autoimmune blistering disease where autoantibodies (IgG4) target **Desmoglein 1 (Dsg1)**. Because Dsg1 is only expressed in the upper layers of the epidermis, the blisters are very fragile and rupture easily, leaving behind "cornflake-like" scales and crusts rather than intact bullae. **Why other options are incorrect:** * **Pemphigus vulgaris (B):** This is the most common and severe form. It involves antibodies against **Desmoglein 3** (and often Dsg1), leading to deeper, suprabasal blisters and frequent mucosal involvement (which is absent in P. foliaceus). * **Pemphigus vegetans (C):** This is a rare variant of Pemphigus vulgaris characterized by vegetating purulent plaques, typically in intertriginous areas (axilla/groin). **High-Yield Clinical Pearls for NEET-PG:** * **Target Antigen:** Dsg1 (P. foliaceus) vs. Dsg3 (P. vulgaris). * **Histopathology:** Subcorneal/Superficial clefting is seen in P. foliaceus. * **Nikolsky Sign:** Positive in all active forms of Pemphigus. * **Mucosal Involvement:** Characteristically **absent** in Pemphigus foliaceus/Fogo Selvagem. * **Immunofluorescence:** "Lace-like" or "Fishnet" pattern of IgG deposition in the intercellular spaces.

Q: Recessive dystrophic epidermolysis bullosa occurs due to an alteration in which type of collagen?

Type 7 collagen. **Explanation:** **Recessive Dystrophic Epidermolysis Bullosa (RDEB)** is a severe mechanobullous disorder characterized by skin fragility and blistering. The correct answer is **Type 7 collagen** because it is the primary component of **anchoring fibrils**. These fibrils are responsible for tethering the basement membrane (lamina densa) to the underlying papillary dermis. In RDEB, mutations in the *COL7A1* gene lead to a deficiency or total absence of Type 7 collagen, causing the sub-epidermal layers to separate easily upon minor trauma. **Analysis of Incorrect Options:** * **Type 4 collagen:** This is a major structural component of the **lamina densa** itself. While vital for the basement membrane zone, it is not the primary defect in dystrophic EB. * **Type 6 collagen:** This type is found in the interstitial matrix and is associated with conditions like Bethlem myopathy or Ullrich congenital muscular dystrophy, not primary blistering skin diseases. * **Type 8 collagen:** This is primarily found in vascular endothelium and Descemet’s membrane in the cornea; it does not play a role in the pathogenesis of Epidermolysis Bullosa. **Clinical Pearls for NEET-PG:** * **Hallmark of Dystrophic EB:** Blistering occurs **below the lamina densa** (sub-lamina densa). * **Clinical Features:** Healing with extensive **scarring**, milia formation, and "mitten-hand" deformity (pseudosyndactyly). * **Complication:** Patients have a significantly high risk of developing aggressive **Squamous Cell Carcinoma (SCC)** in chronic scars. * **Memory Aid:** "Dystrophic = Deeper (Type 7) | Junctional = Junction (Laminin 332) | Simplex = Superficial (Keratin 5/14)."

Q: In Pemphigus Vulgaris, autoantibodies are formed against which of the following cell adhesion molecules?

Cadherin. **Explanation:** **Pemphigus Vulgaris (PV)** is an autoimmune blistering disease characterized by the loss of cell-to-cell adhesion between keratinocytes, a process known as **acantholysis**. 1. **Why Cadherin is correct:** The primary pathology in PV involves IgG autoantibodies directed against **Desmogleins (Dsg1 and Dsg3)**. Desmogleins are transmembrane glycoproteins that belong to the **Cadherin** superfamily of calcium-dependent cell adhesion molecules. They are the core components of **desmosomes**, which provide structural integrity to the epidermis. In PV, Dsg3 (with or without Dsg1) is targeted, leading to intraepidermal cleavage just above the basal layer (suprabasal split). 2. **Why other options are incorrect:** * **Selectins:** These are involved in the "rolling" phase of leukocyte extravasation during inflammation, not in stable cell-to-cell adhesion in the epidermis. * **Integrins:** These primarily mediate cell-to-matrix adhesion (binding cells to the basement membrane). They are involved in diseases like Cicatricial Pemphigoid, not Pemphigus. * **IGSF CAM (Immunoglobulin Superfamily):** These molecules (like ICAM-1 and VCAM-1) are involved in immune cell interactions and firm adhesion during leukocyte migration. **High-Yield Clinical Pearls for NEET-PG:** * **Target Antigens:** PV = Dsg3 (Mucosal) and Dsg1 (Cutaneous); Pemphigus Foliaceus = Dsg1 only. * **Histopathology:** "Row of tombstones" appearance (basal cells remain attached to the basement membrane via integrins/hemidesmosomes). * **Immunofluorescence:** "Fish-net" or "Lace-like" pattern of IgG/C3 deposits. * **Clinical Signs:** Positive Nikolsky sign and Bulla spread sign (Asboe-Hansen sign). * **Oral Involvement:** PV almost always presents with painful oral erosions before skin blisters appear.

Q: A 26-year-old female presents with an acutely developed rash on her back, elbows, buttocks, and knees, associated with severe pruritus and burning sensation. Biopsy shows immunofluorescence granular deposition of IgA in the papillary dermis, along the epidermal basement membrane zone, and neutrophilic dermatitis within dermal papillae. What is the most appropriate course of management?

Gluten-free diet and Dapsone 100 mg daily. **Explanation:** The clinical presentation and histopathology are classic for **Dermatitis Herpetiformis (DH)**, a cutaneous manifestation of gluten-sensitive enteropathy (Celiac disease). **1. Why Option D is Correct:** The management of DH requires a dual approach: * **Dapsone:** This is the drug of choice for symptomatic relief. It rapidly controls the intense pruritus and prevents new vesicle formation (often within 24–48 hours) by inhibiting neutrophilic chemotaxis. * **Gluten-Free Diet (GFD):** While Dapsone treats the skin symptoms, it does not address the underlying systemic pathology. A strict GFD is the only long-term curative measure. It reduces the need for Dapsone over time, improves associated enteropathy, and decreases the risk of intestinal lymphoma. **2. Why Other Options are Incorrect:** * **Option A:** Systemic steroids like Prednisone are generally ineffective in DH and are not the primary treatment. * **Option B:** While essential, a GFD alone takes months to years to resolve skin lesions. It is insufficient for acute symptomatic management. * **Option C:** Dapsone alone controls the rash but does not treat the underlying gluten sensitivity or the associated risk of malignancy. **High-Yield Clinical Pearls for NEET-PG:** * **Hallmark Pathology:** Subepidermal blister with **neutrophilic microabscesses** at the tips of dermal papillae. * **Direct Immunofluorescence (DIF):** Gold standard; shows **granular IgA deposits** in the dermal papillae. * **Associations:** Strongly linked with HLA-DQ2 and HLA-DQ8. * **Dapsone Pre-requisite:** Always check **G6PD levels** before starting Dapsone to avoid hemolytic anemia. * **Target Antigen:** Epidermal transglutaminase (eTG/TG3).

Q: Suprabasal acantholytic blisters are seen in which condition?

Pemphigus vulgaris. **Explanation:** The hallmark of **Pemphigus vulgaris (PV)** is the presence of **suprabasal acantholytic blisters**. This occurs due to IgG antibodies directed against **Desmoglein 3** (and sometimes Desmoglein 1), which are components of desmosomes. The loss of intercellular adhesion (acantholysis) just above the basal layer results in a "row of tombstones" appearance, where the basal cells remain attached to the basement membrane while the upper layers detach. **Analysis of Options:** * **Pemphigus foliaceus:** Characterized by **subcorneal** (superficial) blisters. The antibodies target Desmoglein 1, which is primarily expressed in the upper layers of the epidermis. * **Bullous pemphigoid:** A **subepidermal** blistering disease. It involves antibodies against BP180 and BP230 in the hemidesmosomes, leading to a split between the epidermis and dermis. * **Dermatitis herpetiformis:** Also a **subepidermal** disease associated with Celiac disease. It is characterized by IgA deposits at the tips of dermal papillae (microabscesses). **High-Yield Clinical Pearls for NEET-PG:** * **Nikolsky Sign:** Positive in PV (due to intraepidermal split) but negative in Bullous pemphigoid. * **Tzanck Smear:** Shows **Acantholytic cells** (Tzanck cells/Tzank cells) which are rounded keratinocytes with hyperchromatic nuclei. * **Immunofluorescence:** PV shows a characteristic **"fish-net" or "lace-like"** pattern of IgG/C3 deposition. * **Clinical Presentation:** PV typically starts with painful **oral ulcers** before progressing to flaccid skin bullae.

Question 1

Familial benign pemphigus is also known as:

Accepted Answer

Hailey-hailey disease.

Answer

Brazilian pemphigus.

Answer

Cicatricial pemphigoid.

Answer

None of the above.

Question 2

Which of the following is true about erythema multiforme?

Accepted Answer

Target lesions are seen

Answer

Triggered mainly by HIV infection

Answer

Full blown prodromal symptoms

Answer

Involvement of mucosa more common

Question 3

Acantholytic cells are typically found in the blister cavity in which of the following conditions?

Accepted Answer

Pemphigus

Answer

Bullous pemphigoid

Answer

Epidermolysis bullosa

Answer

Dermatitis herpetiformis

Question 4

Which of the following is mainly a non-inflammatory blistering disorder?

Accepted Answer

Epidermolysis bullosa

Answer

Dermatitis herpetiformis

Answer

Pemphigus

Answer

Bullous pemphigoid

Question 5

A 50-year-old man has a 2-year history of facial bullae and oral ulcers. A microscopic smear from skin lesions is most likely to disclose what?

Accepted Answer

Acantholytic cells

Answer

Tzanck cells

Answer

Necrosis

Answer

Koilocytosis

Question 6

Which type of pemphigus is also known as Brazilian wild fire?

Accepted Answer

Pemphigus foliaceus

Answer

Pemphigus vulgaris

Answer

Pemphigus vegetans

Answer

None of the above

Question 7

Recessive dystrophic epidermolysis bullosa occurs due to an alteration in which type of collagen?

Accepted Answer

Type 7 collagen

Answer

Type 4 collagen

Answer

Type 6 collagen

Answer

Type 8 collagen

Question 8

In Pemphigus Vulgaris, autoantibodies are formed against which of the following cell adhesion molecules?

Accepted Answer

Cadherin

Answer

Selectin

Answer

Integrin

Answer

IGSF CAM

Question 9

A 26-year-old female presents with an acutely developed rash on her back, elbows, buttocks, and knees, associated with severe pruritus and burning sensation. Biopsy shows immunofluorescence granular deposition of IgA in the papillary dermis, along the epidermal basement membrane zone, and neutrophilic dermatitis within dermal papillae. What is the most appropriate course of management?

Accepted Answer

Gluten-free diet and Dapsone 100 mg daily

Answer

Prednisone 40 mg daily

Answer

Gluten-free diet

Answer

Dapsone 100 mg daily

Question 10

Suprabasal acantholytic blisters are seen in which condition?

Accepted Answer

Pemphigus vulgaris

Answer

Dermatitis herpetiformis

Answer

Bullous pemphigoid

Answer

Pemphigus foliaceus

Blistering Diseases — MCQs

Blistering Diseases — MCQs

On this page

Practice by Chapter

Want unlimited practice?