Blistering Diseases Practice Questions

Q: A patient presents with ill-defined, irregularly shaped, painful gingival erosions of short duration. A few months later, skin lesions were also noticed. On histopathological examination, Tzanck cells were found. What is the probable diagnosis?

Pemphigus vulgaris. **Explanation:** The clinical presentation of painful oral erosions followed by cutaneous involvement is a classic hallmark of **Pemphigus Vulgaris (PV)**. **Why Pemphigus Vulgaris is correct:** PV is an autoimmune blistering disease caused by IgG antibodies against **Desmoglein 3** (primarily oral) and **Desmoglein 1** (skin). * **Oral involvement:** In 50-70% of cases, PV begins in the mouth as fragile blisters that rupture quickly, leaving behind painful, irregular, ill-defined erosions. * **Tzanck Cells:** Histopathology or Tzanck smear reveals **acantholytic cells** (keratinocytes that have lost adhesion). These are rounded, enlarged cells with hyperchromatic nuclei and a perinuclear halo, confirming the diagnosis. **Why other options are incorrect:** * **Lichen Planus:** Typically presents with Wickham striae (reticulate white lines) or "beefy red" erosions. Histopathology shows a band-like lymphocytic infiltrate, not acantholysis. * **Angioneurotic Oedema:** Characterized by transient, painless, non-pitting swelling of deeper dermal/subcutaneous tissues (lips/eyes), not chronic erosions or Tzanck-positive blisters. * **Behcet Syndrome:** Presents with recurrent, well-defined "punched-out" aphthous ulcers. It is a multisystem vasculitis often involving genital ulcers and uveitis, but it does not show Tzanck cells. **High-Yield Pearls for NEET-PG:** 1. **Nikolsky Sign:** Positive in PV (perilesional skin shears off with lateral pressure). 2. **Row of Tombstones:** Characteristic histopathological appearance of the basal layer remaining attached to the basement membrane. 3. **Immunofluorescence:** Direct Immunofluorescence (DIF) shows a **"Fishnet" or "Lace-like"** pattern of IgG/C3 deposits. 4. **Bullous Pemphigoid (Contrast):** Subepidermal blister, Nikolsky negative, involves Desmoglein 180/230, and shows linear IgG on DIF.

Q: A patient has oral ulcer and skin bullae, which are slow to heal. The lesion is:

Suprabasal. ### Explanation The clinical presentation of **oral ulcers** and **skin bullae** that are slow to heal is characteristic of **Pemphigus Vulgaris (PV)**. **Why Suprabasal is Correct:** Pemphigus Vulgaris is an autoimmune condition caused by IgG antibodies against **Desmoglein 3** (primarily mucosal) and **Desmoglein 1** (skin). These antibodies target the desmosomes, which hold keratinocytes together. The loss of adhesion (acantholysis) occurs specifically just above the basal layer. The basal cells remain attached to the basement membrane via hemidesmosomes, creating a characteristic **"row of tombstones"** appearance on histology. This results in a **suprabasal cleft**. **Analysis of Incorrect Options:** * **A. Intradermal:** Blisters in the dermis are rare in primary blistering diseases; they usually occur at the dermo-epidermal junction or within the epidermis. * **C. Epidermal:** While the lesion is within the epidermis, "Suprabasal" is the specific anatomical site required for a diagnosis of PV. "Epidermal" is too broad. * **D. Subcorneal:** This is characteristic of **Pemphigus Foliaceus** (targeting Desmoglein 1 only). These blisters are very superficial, rupture easily, and typically **spare the oral mucosa**. **High-Yield Clinical Pearls for NEET-PG:** * **Nikolsky Sign:** Positive (gentle pressure causes skin to slough). * **Tzanck Smear:** Shows **Acantholytic cells** (Tzanck cells)—large, round keratinocytes with hyperchromatic nuclei. * **Immunofluorescence:** Direct Immunofluorescence (DIF) shows a **"fish-net"** or "lace-like" pattern of IgG/C3 deposits. * **Clinical Tip:** PV usually starts in the mouth ("First to come, last to go"). If a question mentions oral involvement + flaccid bullae, think Pemphigus Vulgaris (Suprabasal). If it mentions tense bullae + no oral involvement, think Bullous Pemphigoid (Subepidermal).

Q: Epidermolysis bullosa occurs due to alteration in the structure of which of the following collagens?

Type 7 collagen. ### Explanation **Correct Option: D. Type 7 Collagen** The correct answer is **Type 7 collagen** because it is the primary component of **anchoring fibrils**. These fibrils are crucial for structural integrity, as they tether the basement membrane (specifically the lamina densa) to the underlying papillary dermis. In **Dystrophic Epidermolysis Bullosa (DEB)**, mutations in the *COL7A1* gene lead to defective or absent Type 7 collagen. This results in sub-epidermal cleavage (blistering) following minimal mechanical trauma. Because the split occurs below the basement membrane, these blisters typically heal with significant scarring and milia formation. **Analysis of Incorrect Options:** * **A. Type 1 Collagen:** This is the most abundant collagen in the body, found in bone, skin, and tendons. Mutations here typically lead to **Osteogenesis Imperfecta** or certain types of Ehlers-Danlos Syndrome, not primary blistering diseases. * **B. Type 4 Collagen:** This is a major structural component of the **lamina densa** (basement membrane). While it is involved in Alport Syndrome (kidney/ear issues) and Goodpasture Syndrome, it is not the primary defect in Epidermolysis Bullosa. * **C. Type 6 Collagen:** This type is associated with interstitial tissues and microfibrils. Mutations are classically linked to **Bethlem Myopathy** and Ullrich congenital muscular dystrophy. **High-Yield Clinical Pearls for NEET-PG:** * **EB Simplex:** Defect in **Keratin 5 and 14** (Basal layer). * **Junctional EB:** Defect in **Laminin 332** (formerly Laminin 5). * **Dystrophic EB:** Defect in **Type 7 Collagen** (Anchoring fibrils). * **Mnemonic:** "7-Up" – Type **7** is **U**nder (below) the basement membrane in the **P**apillary dermis. * **Clinical Sign:** Dystrophic EB is often associated with **pseudosyndactyly** (mitten-hand deformity) due to chronic scarring.

Q: Intraepidermal blisters are seen in which of the following conditions?

Pemphigus foliaceus. **Explanation:** The classification of blistering diseases is based on the anatomical level of cleavage. **Intraepidermal blisters** occur when the split happens within the epidermis due to **acantholysis** (loss of intercellular connections between keratinocytes). **Pemphigus foliaceus (Option B)** is the correct answer because it is a superficial variant of pemphigus. It involves IgG autoantibodies against **Desmoglein-1**, a protein found in the upper layers of the epidermis. This results in a very superficial intraepidermal split, specifically in the **subcorneal layer** (stratum granulosum). **Why the other options are incorrect:** * **Bullous pemphigoid (Option A):** This is a **subepidermal** blistering disease. Autoantibodies target BP180 and BP230 in the hemidesmosomes, causing the entire epidermis to detach from the dermis. * **Dermatitis herpetiformis (Option C):** This is a **subepidermal** disease associated with Celiac disease. It is characterized by IgA deposits in the dermal papillae tips, leading to microabscesses and subepidermal clefting. * **Bullous SLE (Option D):** This is also a **subepidermal** bullous disease caused by antibodies against Type VII collagen (similar to Epidermolysis Bullosa Acquisita). **High-Yield Clinical Pearls for NEET-PG:** 1. **Pemphigus Vulgaris:** Intraepidermal split just above the basal layer (**Suprabasal**), showing a "row of tombstones" appearance. 2. **Nikolsky Sign:** Positive in intraepidermal blisters (Pemphigus) and negative in subepidermal blisters (Bullous Pemphigoid). 3. **Tzanck Smear:** Used to identify acantholytic cells (Tzanck cells) in intraepidermal conditions like Pemphigus and Herpes simplex.

Q: What is the characteristic immunofluorescence pattern observed in pemphigus vulgaris?

Intercellular IgG deposition. **Explanation:** **Pemphigus Vulgaris (PV)** is an autoimmune blistering disease characterized by the loss of cell-to-cell adhesion (acantholysis) in the epidermis. The pathophysiology involves IgG autoantibodies directed against **Desmoglein 3** (and sometimes Desmoglein 1), which are transmembrane glycoproteins of the desmosomes. 1. **Why Option A is Correct:** In Direct Immunofluorescence (DIF), these IgG antibodies bind to the desmosomes located between the keratinocytes. This results in a characteristic **"fishnet" or "chicken-wire" pattern** of intercellular IgG and C3 deposition throughout the epidermis. 2. **Why the other options are incorrect:** * **Option B:** C3 and IgG at the dermo-epidermal junction (DEJ) in a linear pattern is characteristic of **Bullous Pemphigoid**. * **Option C:** Linear IgA deposition at the DEJ is the hallmark of **Linear IgA Bullous Dermatosis**. * **Option D:** Granular IgA deposition at the papillary tips is the pathognomonic finding for **Dermatitis Herpetiformis** (associated with Celiac disease). **High-Yield Clinical Pearls for NEET-PG:** * **Tzanck Smear:** Shows "Acantholytic cells" or **Tzanck cells** (rounded keratinocytes with hyperchromatic nuclei). * **Histopathology:** Shows **suprabasal clefting** and a "row of tombstones" appearance of the basal layer. * **Clinical Signs:** Positive **Nikolsky sign** and Bulla spread sign (Asboe-Hansen sign). * **Involvement:** PV almost always involves the **oral mucosa** first, unlike Bullous Pemphigoid which often spares it.

Q: Subepithelial bullae are seen in which of the following conditions?

Dermatitis herpetiformis. **Explanation:** The classification of blistering diseases is based on the level of cleavage within the skin layers. **Subepithelial (subepidermal) bullae** occur when the split happens at the dermo-epidermal junction, below the epidermis. 1. **Why Dermatitis Herpetiformis (DH) is correct:** DH is a chronic, intensely pruritic autoimmune blistering disease associated with gluten-sensitive enteropathy (Celiac disease). Pathologically, it is characterized by the accumulation of neutrophils at the tips of dermal papillae (microabscesses), leading to a **subepidermal split**. Direct Immunofluorescence (DIF) showing granular IgA deposits in the dermal papillae is the gold standard for diagnosis. 2. **Why the other options are incorrect:** * **Molluscum contagiosum:** This is a viral infection caused by a Poxvirus. It presents as umbilicated papules, not bullae. Histologically, it shows characteristic intracytoplasmic inclusion bodies known as **Henderson-Paterson bodies** within the epidermis. * **Pemphigus:** This group of diseases (e.g., Pemphigus Vulgaris) is characterized by **intraepidermal** blisters. The split occurs above the basal layer due to acantholysis (loss of intercellular connections) caused by antibodies against desmogleins. **High-Yield Clinical Pearls for NEET-PG:** * **Subepidermal Blistering Diseases:** Include Bullous Pemphigoid (tense bullae), Dermatitis Herpetiformis, and Epidermolysis Bullosa Acquisita. * **Intraepidermal Blistering Diseases:** Include Pemphigus Vulgaris (flaccid bullae, positive Nikolsky sign) and Hailey-Hailey disease. * **DH Key Association:** Always look for "scapula/extensor surfaces," "gluten sensitivity," and "granular IgA" in the clinical stem. The treatment of choice is **Dapsone**.

Q: Which bullous disease is characterized by the formation of autoantibodies against antigens of epidermal intercellular junctions?

Pemphigus Vulgaris. ### Explanation **Pemphigus Vulgaris (PV)** is the correct answer because it is the prototype of **intraepidermal** autoimmune blistering diseases. It is characterized by the formation of IgG autoantibodies against **Desmoglein 3** (and sometimes Desmoglein 1), which are transmembrane glycoproteins of the **desmosomes** (intercellular junctions). This leads to **acantholysis**—the loss of cell-to-cell adhesion between keratinocytes—resulting in flaccid blisters. #### Why the other options are incorrect: * **Epidermolysis Bullosa (EB):** This is a group of **genetic/hereditary** mechanobullous disorders caused by mutations in structural proteins (like keratin or collagen), not autoantibodies. * **Dermatitis Herpetiformis (DH):** This is an autoimmune disease associated with Celiac disease, but the antibodies (IgA) target **tissue transglutaminase** and deposit at the **dermal papillae tips**, not the intercellular junctions. * **Bullous Pemphigoid (BP):** While autoimmune, the antibodies target **BP180 and BP230** in the **hemidesmosomes** (dermo-epidermal junction). This results in **subepidermal** blisters, not intercellular separation. #### NEET-PG High-Yield Pearls: * **Nikolsky Sign:** Positive in Pemphigus Vulgaris (due to intraepidermal cleavage) but negative in Bullous Pemphigoid. * **Tzanck Smear:** Shows **Acantholytic cells** (Tzanck cells/Row of tombstone appearance) in PV. * **Direct Immunofluorescence (DIF):** PV shows a characteristic **"Fish-net"** or "Lace-like" pattern of IgG/C3 deposits. * **Clinical Presentation:** PV often starts with **oral ulcers** and presents with flaccid, easily ruptured bullae.

Q: Subepidermal blistering is seen in all of the following conditions except?

Pemphigus. **Explanation:** The level of split in blistering diseases is a high-yield topic for NEET-PG. Blisters are classified based on whether the cleavage occurs within the epidermis (**Intraepidermal**) or below it (**Subepidermal**). **Why Pemphigus is the Correct Answer:** **Pemphigus vulgaris** (and the Pemphigus group in general) is characterized by **intraepidermal** blistering. The underlying mechanism is **acantholysis**—the loss of intercellular connections (desmosomes) between keratinocytes due to IgG antibodies against Desmoglein 3 and 1. Because the split occurs within the epidermis, the blisters are thin-walled, flaccid, and rupture easily (Positive Nikolsky sign). **Analysis of Incorrect Options (Subepidermal Blistering):** * **Dermatitis Herpetiformis:** Characterized by subepidermal neutrophils at the papillary tips (microabscesses). It is associated with Celiac disease and IgA deposits. * **Toxic Epidermal Necrolysis (TEN):** Involves full-thickness epidermal necrosis leading to a subepidermal separation at the dermo-epidermal junction. It is a severe drug reaction. * **Bullous Pemphigoid (Implicitly related):** While not an option, it is the classic subepidermal disease caused by antibodies against BP180/230 in the hemidesmosomes. **NEET-PG High-Yield Pearls:** 1. **Nikolsky Sign:** Positive in Pemphigus (Intraepidermal) and TEN; Negative in Bullous Pemphigoid (Subepidermal). 2. **Tzanck Smear:** Shows "Acantholytic cells" (Tzanck cells) in Pemphigus, but not in subepidermal diseases. 3. **Row of Tombstones:** Histopathological appearance of the basal layer in Pemphigus Vulgaris. 4. **DIF Pattern:** Pemphigus shows a "Fish-net" (lace-like) pattern; Bullous Pemphigoid shows a "Linear" pattern at the BMZ.

Q: A patient presents with bullous lesions. What is the characteristic finding on a Tzanck smear?

Acantholysis. **Explanation:** The **Tzanck smear** is a rapid bedside diagnostic test used in dermatology to examine the base of a vesicle or bulla. The characteristic finding in autoimmune blistering diseases like **Pemphigus Vulgaris** is **Acantholysis**. **1. Why Acantholysis is Correct:** Acantholysis refers to the loss of intercellular connections (desmosomes) between keratinocytes, leading to "rounded-up" detached cells known as **Tzanck cells**. These cells exhibit a large, hyperchromatic nucleus and a peripheral rim of condensed cytoplasm. This process is the hallmark of the Pemphigus group of diseases and is also seen in viral infections (HSV, VZV), though viral cells additionally show multinucleation and Cowdry type A inclusions. **2. Why Other Options are Incorrect:** * **A. Presence of Langerhans cells:** These are antigen-presenting cells found in the stratum spinosum. While they play a role in Histiocytosis X, they are not a diagnostic feature of a Tzanck smear for bullous lesions. * **C. Leukocytosis:** This refers to an elevated white blood cell count in the systemic circulation, usually indicating infection or inflammation; it is not a microscopic finding on a local skin smear. * **D. Absence of melanin pigment:** This is characteristic of vitiligo or albinism, not primary blistering disorders. **Clinical Pearls for NEET-PG:** * **Pemphigus Vulgaris:** Tzanck smear shows acantholytic cells; Immunofluorescence shows a **"fish-net"** pattern. * **Bullous Pemphigoid:** Tzanck smear is typically **negative** for acantholysis (as it is a subepidermal blister); it may show eosinophils. * **Herpes Simplex/Zoster:** Tzanck smear shows **multinucleated giant cells**. * **Mnemonic:** "Tzanck Heavens for Herpes and Pemphigus."

Question 1

A patient presents with ill-defined, irregularly shaped, painful gingival erosions of short duration. A few months later, skin lesions were also noticed. On histopathological examination, Tzanck cells were found. What is the probable diagnosis?

Accepted Answer

Pemphigus vulgaris

Answer

Lichen planus

Answer

Angioneurotic oedema

Answer

Behcet syndrome

Question 2

A patient has oral ulcer and skin bullae, which are slow to heal. The lesion is:

Accepted Answer

Suprabasal

Answer

Intradermal

Answer

Epidermal

Answer

Sub corneal

Question 3

An 82-year-old man presents with a 1 and a half-week history of severe pruritus and eczema. His past medical history includes atopic dermatitis, thyroid disease, and multiple sclerosis. On physical examination, he has dozens of 1-2 cm tense bullae and several erosions over his upper and lower extremities. His oral mucosa is not involved. Nikolsky sign is negative. A skin biopsy is taken and anti-BP 180 is detected in his blood. A potent topical steroid is prescribed. What is the most likely diagnosis?

Accepted Answer

Bullous pemphigoid

Answer

Pemphigus vulgaris

Answer

Necrotising pemphigus

Answer

Contact eczema

Question 4

Epidermolysis bullosa occurs due to alteration in the structure of which of the following collagens?

Accepted Answer

Type 7 collagen

Answer

Type 1 collagen

Answer

Type 4 collagen

Answer

Type 6 collagen

Question 5

Intraepidermal blisters are seen in which of the following conditions?

Accepted Answer

Pemphigus foliaceus

Answer

Bullous pemphigoid

Answer

Dermatitis herpetiformis

Answer

Bullous SLE

Question 6

What is the characteristic immunofluorescence pattern observed in pemphigus vulgaris?

Accepted Answer

Intercellular IgG deposition

Answer

C3 and IgG deposition at the dermo-epidermal junction

Answer

IgA deposition at the dermo-epidermal junction

Answer

IgA deposition at the papillary tips

Question 7

Subepithelial bullae are seen in which of the following conditions?

Accepted Answer

Dermatitis herpetiformis

Answer

Molluscum contagiosum

Answer

Pemphigus

Answer

All of the above

Question 8

Which bullous disease is characterized by the formation of autoantibodies against antigens of epidermal intercellular junctions?

Accepted Answer

Pemphigus Vulgaris

Answer

Epidermolysis bullosa

Answer

Dermatitis herpetiformis

Answer

Bullous pemphigoid

Question 9

Subepidermal blistering is seen in all of the following conditions except?

Accepted Answer

Pemphigus

Answer

Pemphigus vulgaris

Answer

Dermatitis herpetiformis

Answer

Toxic epidermal necrolysis

Question 10

A patient presents with bullous lesions. What is the characteristic finding on a Tzanck smear?

Accepted Answer

Acantholysis

Answer

Presence of Langerhans cells

Answer

Leukocytosis

Answer

Absence of melanin pigment

Blistering Diseases — MCQs

Blistering Diseases — MCQs

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