Blistering Diseases Practice Questions

Q: Intercellular antibody deposition on immunofluorescence is seen in which of the following conditions?

Pemphigus. **Explanation:** The hallmark of the **Pemphigus** group of diseases (e.g., Pemphigus Vulgaris, Pemphigus Foliaceus) is the presence of IgG antibodies directed against **desmogleins** (transmembrane glycoproteins of desmosomes). On Direct Immunofluorescence (DIF), these antibodies bind to the cell surfaces of keratinocytes throughout the epidermis, resulting in a characteristic **"fishnet" or "lace-like" intercellular pattern**. This process leads to acantholysis (loss of cell-to-cell adhesion) and the formation of intraepidermal blisters. **Analysis of Incorrect Options:** * **Pemphigoid (Bullous Pemphigoid):** Characterized by antibodies against BP180 and BP230 in the hemidesmosomes. DIF shows **linear deposition** of IgG and C3 along the **basement membrane zone (BMZ)**, not intercellularly. * **Porphyria (Porphyria Cutanea Tarda):** Shows deposition of immunoglobulins (mainly IgG) and complement around the **dermal blood vessel walls** and linearly along the BMZ, but not intercellularly. * **Psoriasis:** This is an inflammatory papulosquamous disorder, not a primary immunobullous disease. Diagnosis is clinical and histological (Munro’s microabscesses); DIF is typically negative. **High-Yield Clinical Pearls for NEET-PG:** * **Pemphigus Vulgaris:** Most common type; involves mucosa; Nikolsky sign is positive; Tzanck smear shows **Acantholytic (Tzanck) cells**. * **DIF Pattern Summary:** * **Fishnet/Intercellular:** Pemphigus. * **Linear BMZ:** Bullous Pemphigoid, Epidermolysis Bullosa Acquisita. * **Granular/Dermal Papillae:** Dermatitis Herpetiformis (IgA). * **Antigens:** Pemphigus Vulgaris (Dsg 3 > 1); Pemphigus Foliaceus (Dsg 1).

Q: Toxic epidermal necrolysis (TEN) typically involves what percentage of body surface area?

Greater than 30%. **Explanation:** The classification of Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) is based strictly on the percentage of **Body Surface Area (BSA)** affected by epidermal detachment. These conditions represent a spectrum of the same disease process, typically triggered by a hypersensitivity reaction to drugs (e.g., Sulfonamides, Antiepileptics, NSAIDs). * **SJS (Option A):** Involves **less than 10%** of the total BSA. It is the less severe end of the spectrum but still carries significant morbidity. * **SJS/TEN Overlap (Option B & C):** Involves **10% to 30%** of the BSA. This is a transitional zone where the disease is progressing beyond localized involvement. * **TEN (Option D):** Defined by epidermal detachment involving **greater than 30%** of the BSA. This is the most severe form, characterized by extensive "scalded" skin appearance and high mortality rates due to sepsis and fluid loss. **High-Yield Clinical Pearls for NEET-PG:** * **Pathology:** Characterized by widespread keratinocyte apoptosis mediated by **Fas-Fas ligand** interactions and **Granulysin**. * **Nikolsky Sign:** Positive (gentle pressure on the skin causes the epidermis to shear off). * **Mucosal Involvement:** Occurs in >90% of cases (oral, ocular, and genital). * **SCORTEN:** A prognostic scoring system used to predict mortality in SJS/TEN based on parameters like age, heart rate, malignancy, urea, and glucose. * **Management:** Immediate cessation of the offending drug and supportive care in a Burn Unit or ICU. Cyclosporine and IVIG are often considered as medical therapies.

Q: Coeliac disease is commonly associated with which bullous dermatosis?

Dermatitis herpetiformis. **Explanation:** **Dermatitis Herpetiformis (DH)** is the correct answer because it is considered the cutaneous manifestation of gluten-sensitive enteropathy (**Coeliac disease**). Both conditions share the same genetic predisposition (HLA-DQ2 and HLA-DQ8). In DH, IgA antibodies are formed against **epidermal transglutaminase (eTG)**, which cross-react with **tissue transglutaminase (tTG)** found in the gut. This leads to the characteristic subepidermal blisters and intense pruritus. **Analysis of Incorrect Options:** * **B. Erythema Multiforme:** This is a hypersensitivity reaction typically triggered by infections (most commonly Herpes Simplex Virus) or drugs. It is not linked to gluten sensitivity. * **C. Bullous Pemphigoid:** An autoimmune subepidermal blistering disease caused by IgG antibodies against BP180 and BP230. It is primarily seen in the elderly and has no association with Coeliac disease. * **D. Pemphigus Vulgaris:** An intraepidermal blistering disease caused by antibodies against Desmoglein 1 and 3. It involves the mucous membranes and skin but is not related to malabsorption syndromes. **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Presentation:** Intensely pruritic, grouped (herpetiform) vesicles typically located on **extensor surfaces** (elbows, knees, buttocks). * **Histopathology:** Characterized by **neutrophilic microabscesses** at the tips of dermal papillae. * **Direct Immunofluorescence (DIF):** The gold standard for diagnosis, showing **granular IgA deposits** at the dermo-epidermal junction (tips of dermal papillae). * **Treatment:** The drug of choice is **Dapsone** (provides rapid symptomatic relief), but a **Gluten-Free Diet (GFD)** is essential for long-term management and resolving the underlying enteropathy.

Q: In pemphigus foliaceous, acantholysis is seen in which layer of the epidermis?

Stratum basale. **Explanation:** In **Pemphigus Foliaceus (PF)**, the pathology is characterized by **subcorneal acantholysis**. The autoantibodies (IgG) are directed against **Desmoglein 1 (Dsg1)**. Since Dsg1 is primarily expressed in the upper layers of the epidermis, the loss of cell-to-cell adhesion occurs superficially, specifically in the **stratum granulosum**. *Note: There appears to be a discrepancy in the provided key. In standard dermatopathology, PF occurs in the granular layer, while Pemphigus Vulgaris occurs just above the basal layer.* **Analysis of Options:** * **Stratum Granulosum (Correct Pathological Site):** This is the classic site for PF. Because the split is so superficial, the blisters are fragile and often present clinically as erosions or "corn-flake" scales rather than intact bullae. * **Stratum Basale (Incorrect):** This layer remains attached to the basement membrane in Pemphigus Vulgaris, creating the "tombstone appearance." Acantholysis *at* the basal layer is not characteristic of PF. * **Stratum Corneum (Incorrect):** While the split is "subcorneal," the actual cellular breakdown (acantholysis) occurs in the living cells of the granulosum immediately beneath it. * **Spinous Layer (Incorrect):** This is the site of acantholysis in **Pemphigus Vulgaris**, where antibodies target **Desmoglein 3** (and Dsg1), leading to deeper, suprabasal clefting. **NEET-PG High-Yield Pearls:** 1. **Target Antigen:** Dsg1 only (PF); Dsg3 +/- Dsg1 (PV). 2. **Clinical Sign:** Nikolsky sign is positive in both, but PF lacks mucosal involvement (Dsg3 compensates in mucosa). 3. **Immunofluorescence:** "Fish-net" or "Lace-like" IgG deposition in the intercellular spaces. 4. **Fogo Selvagem:** An endemic form of Pemphigus Foliaceus linked to black fly bites (Simulium species).

Q: A patient presents with extremely pruritic excoriations and papules on their buttocks. Immunohistological examination of normal perilesional skin shows autoantibodies against epidermal transglutaminase and IgA deposition in the dermis. What is the diagnosis?

Dermatitis herpetiformis. **Explanation:** The clinical presentation and immunohistopathology are diagnostic of **Dermatitis Herpetiformis (DH)**. **Why the correct answer is right:** Dermatitis herpetiformis is a chronic, intensely pruritic autoimmune blistering disease strongly associated with **Celiac disease** (gluten-sensitive enteropathy). * **Clinical Presentation:** Characterized by symmetric, grouped (herpetiform) papulovesicles on extensor surfaces (buttocks, elbows, knees). Due to intense itching, patients often present with only **excoriations**. * **Immunopathology:** The hallmark is **granular IgA deposition** in the dermal papillae tips. The target autoantigen is **epidermal transglutaminase (eTG)**, which cross-reacts with tissue transglutaminase (tTG) found in the gut. **Why incorrect options are wrong:** * **Pemphigus vulgaris:** Characterized by flaccid bullae and oral mucosal involvement. Immunofluorescence shows **IgG** and C3 in a "fishnet" pattern against desmogleins, not IgA. * **Bullous Pemphigoid:** Presents with tense bullae in the elderly. Immunofluorescence shows **linear IgG** and C3 along the basement membrane zone (BMZ). * **Linear IgA disease:** While it involves IgA, the deposition is **linear** along the BMZ, not granular in the dermal papillae, and it is not typically associated with gluten sensitivity. **NEET-PG High-Yield Pearls:** * **Gold Standard Diagnosis:** Direct Immunofluorescence (DIF) of **perilesional** skin showing granular IgA. * **Associated HLA:** HLA-DQ2 and HLA-DQ8. * **Treatment of Choice:** **Dapsone** (provides rapid symptomatic relief) and a strict **Gluten-free diet** (long-term management). * **Histology:** Shows **neutrophilic microabscesses** at the tips of dermal papillae.

Q: A 2-day-old newborn girl, born out of a non-consanguinous marriage, was evaluated for tense blisters and areas of denuded skin that had been present since birth. The child develops these lesions while the mother handles her for bathing and feeding. The sibling of the child also has a history of developing similar lesions. What is the most likely diagnosis?

Congenital epidermolysis bullosa. ### Explanation **Correct Option: B. Congenital epidermolysis bullosa (EB)** The clinical presentation of **tense blisters** and **denuded skin** present since birth, triggered by minor mechanical trauma (handling for bathing/feeding), is the hallmark of **Epidermolysis Bullosa**. This is a group of genetic mechanobullous disorders characterized by skin fragility due to mutations in structural proteins (like keratins, laminin, or collagen). The positive family history (sibling affected) further supports a genetic etiology. **Why the other options are incorrect:** * **A. Congenital Syphilis:** Typically presents with a maculopapular rash, snuffles, or hemorrhagic bullae on palms and soles. It is not triggered by mechanical friction and usually lacks a sibling history of similar lesions. * **C. Langerhans Cell Histiocytosis (LCH):** In neonates, LCH usually presents as seborrheic dermatitis-like crusting, petechiae, or reddish-brown papules, rather than mechanobullous blistering. * **D. Congenital Bullous Ichthyosiform Erythroderma (Epidermolytic Ichthyosis):** While it presents with blisters at birth, it is characterized by generalized **erythroderma** (redness) and subsequent thick, verrucous scaling, which is absent in this case. **High-Yield Clinical Pearls for NEET-PG:** * **Nikolsky Sign:** Often positive in EB (especially EB Simplex). * **Classification:** 1. **EB Simplex:** Intraepidermal cleavage (Keratin 5/14 mutation). 2. **Junctional EB:** Cleavage at Lamina Lucida (Laminin 332 mutation). 3. **Dystrophic EB:** Sub-lamina densa cleavage (Type VII Collagen mutation); often leads to scarring and "mitten-hand" deformity. * **Management:** Primarily supportive; "non-adherent dressings" and avoiding trauma are key. * **Differential Diagnosis:** Always rule out Staphylococcal Scalded Skin Syndrome (SSSS) and Neonatal Pemphigus in blistering neonates.

Q: Which of the following conditions is characterized by the presence of typical lesions that manifest as target lesions?

Erythema Multiforme. **Explanation:** **Erythema Multiforme (EM)** is the classic condition associated with **target (iris) lesions**. These lesions typically consist of three concentric zones: a central dusky/blistering area, an intermediate pale edematous ring, and a peripheral erythematous halo. This hypersensitivity reaction is most commonly triggered by infections, particularly **Herpes Simplex Virus (HSV)** and *Mycoplasma pneumoniae*. **Why other options are incorrect:** * **Pemphigus (Vulgaris/Foliaceus):** Characterized by flaccid bullae and a positive Nikolsky sign due to acantholysis (loss of cell-to-cell adhesion). It does not present with targetoid morphology. * **Bullous Pemphigoid:** Presents as large, tense subepidermal bullae on an erythematous base, typically in the elderly. The primary pathology is at the dermo-epidermal junction (anti-BP180/230). * **Dermatitis Herpetiformis:** Characterized by intensely pruritic, grouped (herpetiform) vesicles on the extensors, strongly associated with Celiac disease and IgA deposits in dermal papillae. **High-Yield Clinical Pearls for NEET-PG:** * **EM Minor vs. Major:** EM Major involves at least two mucosal surfaces and is more severe, whereas EM Minor involves minimal to no mucosal involvement. * **Target Lesion Anatomy:** True target lesions have **three** distinct zones. "Atypical" target lesions (two zones) are more characteristic of Stevens-Johnson Syndrome (SJS). * **Histopathology:** EM shows interface dermatitis with necrotic keratinocytes. * **Most Common Trigger:** HSV-1 is the most frequent precipitant of recurrent EM.

Q: Sub-epidermal splitting is not found in which of the following conditions?

Pemphigus foliaceus. **Explanation:** The level of splitting in blistering diseases is determined by the specific target of the autoimmune or physical insult. Blisters are categorized as **intra-epidermal** (within the epidermis) or **sub-epidermal** (below the epidermis/at the dermo-epidermal junction). **Why Pemphigus Foliaceus is the correct answer:** Pemphigus foliaceus is an autoimmune disease where antibodies target **Desmoglein-1**. Since Desmoglein-1 is located in the upper layers of the epidermis, the split occurs high up in the **stratum granulosum**. This results in a very superficial, **intra-epidermal** blister. Because the roof is so thin, these blisters rupture easily, often presenting clinically as scales or crusts rather than intact bullae. **Analysis of incorrect options (Sub-epidermal splitting present):** * **Bullous Pemphigoid:** Antibodies target BP180 and BP230 in the hemidesmosomes. This causes the entire epidermis to detach from the dermis, resulting in a **sub-epidermal** split and tense bullae. * **Dermatitis Herpetiformis:** IgA deposits at the tips of dermal papillae lead to neutrophilic microabscesses and subsequent **sub-epidermal** separation. * **Burns:** Second-degree (partial-thickness) burns typically involve thermal damage that leads to fluid accumulation at the **dermo-epidermal junction**, causing sub-epidermal cleavage. **High-Yield Clinical Pearls for NEET-PG:** * **Pemphigus Vulgaris:** Split is **suprabasal** (intra-epidermal) due to Desmoglein-3 antibodies; shows "row of tombstones" appearance. * **Nikolsky Sign:** Positive in intra-epidermal conditions (Pemphigus) and negative in sub-epidermal conditions (Bullous Pemphigoid). * **Mnemonic:** "Foliaceus is Foliage" (Top of the tree/surface); "Vulgaris is Deep" (Bottom/suprabasal).

Q: A female patient presents with tense bullae on an erythematous base. What is the most likely diagnosis?

Bullous pemphigoid. ### Explanation **Correct Answer: B. Bullous pemphigoid** **Why it is correct:** The clinical hallmark of **Bullous Pemphigoid (BP)** is the presence of **tense bullae** on an erythematous or eczematous base. This occurs because BP is a **subepidermal** blistering disease. The autoantibodies (anti-BP180 and anti-BP230) target the hemidesmosomes at the dermo-epidermal junction. Because the entire thickness of the epidermis forms the roof of the blister, it is structurally strong and "tense," making it less likely to rupture easily. **Why the other options are incorrect:** * **Pemphigus vulgaris (C):** This is an **intraepidermal** disease (acantholysis). Because the blister roof is very thin (only the upper layers of the epidermis), the bullae are **flaccid** and rupture easily, often presenting as erosions. * **Pemphigus erythematosus (A) and Pemphigus vegetans (D):** These are variants of the Pemphigus group. Like Pemphigus vulgaris, they involve intraepidermal splitting and do not typically present with the classic "tense" bullae seen in subepidermal pathologies. **NEET-PG High-Yield Pearls:** * **Nikolsky Sign:** Negative in Bullous Pemphigoid; Positive in Pemphigus Vulgaris. * **Direct Immunofluorescence (DIF):** Shows **linear** IgG and C3 deposits along the basement membrane zone in BP. (In Pemphigus, it shows a "fish-net" or "lace-like" pattern). * **Demographics:** BP typically affects the elderly (60+ years), whereas Pemphigus often affects middle-aged adults (40–60 years). * **Mucosal involvement:** Common and severe in Pemphigus vulgaris; rare and usually mild in Bullous Pemphigoid.

Question 1

Intercellular antibody deposition on immunofluorescence is seen in which of the following conditions?

Accepted Answer

Pemphigus

Answer

Psoriasis

Answer

Pemphigoid

Answer

Porphyria

Question 2

Itching associated with linear IgA deposition in dermal papillae is a feature of which of the following conditions?

Accepted Answer

Dermatitis herpetiformis

Answer

Bullous disease of childhood

Answer

Lichenoid bullous disease

Answer

Pemphigus vulgaris

Question 3

Toxic epidermal necrolysis (TEN) typically involves what percentage of body surface area?

Accepted Answer

Greater than 30%

Answer

Less than 10%

Answer

10-20%

Answer

20-30%

Question 4

Coeliac disease is commonly associated with which bullous dermatosis?

Accepted Answer

Dermatitis herpetiformis

Answer

Erythema multiforme

Answer

Bullous pemphigoid

Answer

Pemphigus vulgaris

Question 5

In pemphigus foliaceous, acantholysis is seen in which layer of the epidermis?

Accepted Answer

Stratum basale

Answer

Stratum corneum

Answer

Stratum granulosum

Answer

Spinous layer

Question 6

A patient presents with extremely pruritic excoriations and papules on their buttocks. Immunohistological examination of normal perilesional skin shows autoantibodies against epidermal transglutaminase and IgA deposition in the dermis. What is the diagnosis?

Accepted Answer

Dermatitis herpetiformis

Answer

Pemphigus vulgaris

Answer

Pemphigoid

Answer

Linear IgA disease

Question 7

A 2-day-old newborn girl, born out of a non-consanguinous marriage, was evaluated for tense blisters and areas of denuded skin that had been present since birth. The child develops these lesions while the mother handles her for bathing and feeding. The sibling of the child also has a history of developing similar lesions. What is the most likely diagnosis?

Accepted Answer

Congenital epidermolysis bullosa

Answer

Congenital syphilis

Answer

Langerhans cell histiocytosis

Answer

Congenital bullous ichthyosiform erythroderma

Question 8

Which of the following conditions is characterized by the presence of typical lesions that manifest as target lesions?

Accepted Answer

Erythema Multiforme

Answer

Pemphigus

Answer

Bullous pemphigoid

Answer

Dermatitis Herpetiformis

Question 9

Sub-epidermal splitting is not found in which of the following conditions?

Accepted Answer

Pemphigus foliaceus

Answer

Bullous pemphigoid

Answer

Dermatitis herpetiformis

Answer

Burns

Question 10

A female patient presents with tense bullae on an erythematous base. What is the most likely diagnosis?

Accepted Answer

Bullous pemphigoid

Answer

Pemphigus erythematosus

Answer

Pemphigus vulgaris

Answer

Pemphigus vegetans

Blistering Diseases — MCQs

Blistering Diseases — MCQs

On this page

Practice by Chapter

Want unlimited practice?