Blistering Diseases Practice Questions

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: 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."

Q: U-serrated pattern in direct immunofluorescence is seen in:

Epidermolysis bullosa acquisita. ### Explanation The correct answer is **Epidermolysis bullosa acquisita (EBA)**. **1. Why EBA is correct:** Direct Immunofluorescence (DIF) of perilesional skin in subepidermal autoimmune bullous diseases typically shows linear IgG and C3 deposits along the basement membrane zone (BMZ). However, using **Salt-Split Skin (SSS)** or high-resolution DIF, two distinct patterns emerge: * **U-serrated pattern:** Characteristic of **EBA**. The immune deposits occur below the lamina densa (targeting Type VII collagen). These deposits follow the contours of the dermal papillae, resembling the letter "U" or "grass-like" arcs. * **N-serrated pattern:** Characteristic of **Bullous Pemphigoid**. The deposits occur in the lamina lucida (targeting BP180/230), appearing as "saw-tooth" or "N" shapes. **2. Why other options are incorrect:** * **Bullous pemphigoid:** Shows an **N-serrated pattern** on DIF. On Salt-split skin, the fluorescence is on the **roof** (epidermal side). * **Linear IgA disease:** Characterized by linear deposits of **IgA** (not IgG) along the BMZ. It does not typically show the U-serrated morphology. * **Dermatitis herpetiformis:** Shows **granular IgA deposits** at the tips of dermal papillae, not a linear serrated pattern. **3. High-Yield Clinical Pearls for NEET-PG:** * **Target Antigen in EBA:** Type VII Collagen (anchoring fibrils). * **Salt-Split Skin Test:** In EBA, the fluorescence is on the **floor** (dermal side) of the split. In Bullous Pemphigoid, it is on the **roof** (epidermal side). * **Clinical variants of EBA:** Mechanobullous (classic) and Inflammatory (resembling BP). * **Mnemonic:** **E**BA = **B**ottom (Floor) / **U**-serrated. **B**P = **T**op (Roof) / **N**-serrated.

Q: All are true about Dermatitis herpetiformis EXCEPT:

Lesions have epidermal bullae. ### Explanation **Dermatitis Herpetiformis (DH)** is a chronic, autoimmune blistering disease characterized by intensely pruritic, grouped vesicles. The correct answer is **B** because DH is a **subepidermal** blistering disease, not epidermal. #### 1. Why Option B is the Correct Answer (The Exception) In DH, the primary pathology occurs at the **dermo-epidermal junction**. Neutrophils accumulate at the tips of the dermal papillae (forming **microabscesses**), leading to the separation of the epidermis from the dermis. This results in **subepidermal bullae**. Intraepidermal or "epidermal" bullae are characteristic of the Pemphigus group of diseases, not DH. #### 2. Analysis of Other Options * **Option A:** DH is notoriously known as "the itch that rashes." The pruritus is so intense that patients often present with excoriations and crusts rather than intact vesicles. * **Option C:** The gold standard for diagnosis is Direct Immunofluorescence (DIF) of perilesional skin, which shows **granular IgA deposits** localized in the **papillary tips**. * **Option D:** DH is considered the cutaneous manifestation of **Celiac disease**. Nearly 90% of patients have associated gluten-sensitive enteropathy (though it may be asymptomatic), and both conditions share the **HLA-DQ2/DQ8** haplotype. #### 3. High-Yield Clinical Pearls for NEET-PG * **Distribution:** Symmetrical involvement of extensors (elbows, knees, buttocks, and scalp). * **Histopathology:** Neutrophilic microabscesses at the dermal papillary tips (Pierard’s microabscesses). * **Treatment of Choice:** **Dapsone** (provides rapid relief from itching) along with a strict **Gluten-Free Diet (GFD)**. * **Target Antigen:** Epidermal Transglutaminase (eTG/TG3).

Q: Intra-epithelial split is seen in which of the following conditions?

Pemphigus vulgaris. **Explanation:** The level of split in blistering diseases is a high-yield concept for NEET-PG. Blisters are classified based on whether the cleavage occurs within the epidermis (**Intra-epidermal/Intra-epithelial**) or below it (**Sub-epidermal**). **1. Why Pemphigus Vulgaris is correct:** Pemphigus vulgaris is an autoimmune disease characterized by IgG antibodies against **Desmoglein 3** (and 1). These proteins are components of desmosomes, which hold keratinocytes together. The destruction of these "bridges" leads to **acantholysis** (loss of intercellular adhesion), resulting in an **intra-epithelial split**. Specifically, in Pemphigus Vulgaris, the split occurs just above the basal layer, creating a "tombstone appearance." **2. Why other options are incorrect:** * **Bullous Pemphigoid:** This is a **sub-epidermal** blistering disease. Autoantibodies (anti-BP180 and BP230) target the hemidesmosomes at the dermo-epidermal junction, causing the entire epidermis to lift off the dermis. * **Epidermolysis Bullosa (EB):** While EB Simplex is intra-epidermal, the term "Epidermolysis Bullosa" generally encompasses a group of genetic disorders where the majority of types (Junctional and Dystrophic) involve **sub-epidermal** cleavage. In the context of standard MCQ patterns, Pemphigus is the classic prototype for intra-epithelial splits. **Clinical Pearls for NEET-PG:** * **Nikolsky Sign:** Positive in Pemphigus (intra-epidermal) and negative in Bullous Pemphigoid (sub-epidermal). * **Tzanck Smear:** Shows **Acantholytic cells** (Tzanck cells) in Pemphigus. * **DIF Pattern:** Pemphigus shows a **"Fish-net"** or "Lace-like" pattern; Bullous Pemphigoid shows a **Linear** pattern along the basement membrane zone.

Q: A 12-year-old male presented with intensely itchy grouped vesicles on the buttock, trunk, and scalp. On exposure to wheat, they exaggerate. What is the diagnosis?

Dermatitis herpetiformis. ### Explanation **Correct Answer: B. Dermatitis herpetiformis** **Concept:** Dermatitis herpetiformis (DH) is a chronic, autoimmune blistering disease characterized by intensely pruritic, symmetric, grouped vesicles (herpetiform) typically involving the extensor surfaces (elbows, knees), buttocks, and scalp. The hallmark of DH is its strong association with **Gluten-Sensitive Enteropathy (Celiac Disease)**. The ingestion of wheat (gluten) triggers the production of IgA antibodies against tissue transglutaminase (tTG), which cross-react with epidermal transglutaminase (eTG), leading to subepidermal blister formation. **Why the other options are incorrect:** * **Herpes simplex:** While it presents with grouped vesicles, it is typically localized (e.g., labial or genital), acute, and not triggered by dietary wheat. * **Pemphigus vulgaris:** This is an intraepidermal blistering disease characterized by flaccid bullae and painful oral erosions. It is not intensely itchy and lacks the dietary association with gluten. * **Bullous impetigo:** A superficial bacterial infection (usually *S. aureus*) presenting with fragile bullae that leave a "collarette" of scale. It is common in children but is not chronic or triggered by wheat. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Diagnosis:** Direct Immunofluorescence (DIF) showing **granular IgA deposits** at the tips of dermal papillae. * **Histopathology:** Characterized by **neutrophilic microabscesses** (Papillary tip abscesses) and subepidermal clefting. * **Treatment of Choice:** **Dapsone** (provides rapid relief of itch) along with a strict **Gluten-Free Diet**. * **Associated HLA:** Strongly associated with **HLA-DQ2** and **HLA-DQ8**.

Q: Granular deposit of IgA at the dermoepidermal junction is seen in which of the following conditions?

Dermatitis herpetiformis. **Explanation:** The correct answer is **Dermatitis herpetiformis (DH)**. This condition is a cutaneous manifestation of gluten-sensitive enteropathy (Celiac disease). The hallmark immunopathological finding in DH is the **granular deposition of IgA** at the tips of the dermal papillae (dermoepidermal junction). These deposits are directed against **epidermal transglutaminase (eTG)**. **Why the other options are incorrect:** * **Pemphigus vulgaris:** Characterized by **IgG and C3** deposits in a **"fish-net" or "lace-like"** pattern within the epidermis (intercellular), targeting Desmoglein 3. * **Bullous pemphigoid:** Shows **linear** (not granular) deposition of **IgG and C3** along the basement membrane zone (BMZ), targeting BP180 and BP230. * **Pemphigus foliaceus:** Similar to Pemphigus vulgaris, it shows a **fish-net IgG** pattern, but it is localized to the superficial layers of the epidermis, targeting Desmoglein 1. **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Presentation:** Intensely pruritic, grouped vesicles (herpetiform) symmetrically distributed on extensor surfaces (elbows, knees, buttocks). * **Histopathology:** Characterized by **neutrophilic microabscesses** (Papillary tip abscesses) and subepidermal blisters. * **Association:** Strongly associated with **HLA-DQ2 and HLA-DQ8**. * **Treatment of Choice:** **Dapsone** (provides rapid symptomatic relief) along with a strict **gluten-free diet**. * **Gold Standard Diagnosis:** Direct Immunofluorescence (DIF) of perilesional skin showing granular IgA.

Q: A 25-year-old office assistant in a multinational company was taking diclofenac sodium for low back ache for last few weeks. She presents with the following skin lesions. All are true about the image shown except:

$>30 \%$ BSA involvement in Stevens-Johnson syndrome. ***>30% BSA involvement in Stevens-Johnson syndrome*** - Stevens-Johnson syndrome (SJS) is defined by skin detachment affecting **less than 10%** of the body surface area (BSA). - Involvement of **>30% BSA** is characteristic of **Toxic Epidermal Necrolysis (TEN)**, which is a more severe form on the SJS-TEN spectrum. - Therefore, this statement is **FALSE** for SJS and is the correct answer to this "except" question. *Hemorrhagic crusting of lips* - The image shows extensive **hemorrhagic crusting and erosions** on the lips, which is a hallmark feature of SJS/TEN. - This mucosal involvement causes significant pain, difficulty eating, and increased infection risk. - This statement is **TRUE** about the condition shown. *Apoptotic keratinocytes* - Histopathologically, SJS and TEN are characterized by widespread **keratinocyte apoptosis**, leading to full-thickness epidermal necrosis and detachment. - This programmed cell death is the key pathophysiologic mechanism underlying the severe skin damage. - This statement is **TRUE** about SJS/TEN. *Systemic involvement leads to lung and kidney malfunction* - SJS/TEN can cause **severe systemic complications** affecting multiple organs including lungs (pneumonitis, ARDS), kidneys (acute tubular necrosis), liver, and GI tract. - Systemic complications and secondary infections are major causes of morbidity and mortality. - This statement is **TRUE** about severe SJS/TEN cases.

Q: A patient presents with intensely pruritic vesicular lesions on extensor surfaces. What is the most likely diagnosis based on the clinical image?

Dermatitis herpetiformis. ***Dermatitis herpetiformis*** - This image shows **urticarial plaques** and **grouped vesicles/bullae**, which are classic features of **dermatitis herpetiformis**. - These lesions are typically **extremely pruritic**, often appearing symmetrically on extensor surfaces like the elbows, knees, and buttocks. *Psoriasis* - Psoriasis typically presents as well-demarcated, **erythematous plaques** with **silvery scales**, predominantly on extensor surfaces and the scalp. - While it can involve various morphologies, the vesicular nature seen in the image is not characteristic of typical psoriasis. *Erythema marginatum* - Erythema marginatum is characterized by **pink or red macular lesions** with **raised, serpiginous borders** that are typically non-pruritic and rapidly migratory. - It is a minor criterion for **rheumatic fever** and looks distinctly different from the vesicular eruption shown. *Lichen planus* - Lichen planus presents with "6 Ps": **pruritic, purple, polygonal, planar, papules, and plaques**, often with **Wickham's striae** (fine white lines). - It usually affects the wrists, ankles, and oral mucosa, and does not typically feature the prominent vesicles or bullae seen in the image.

Q: All are true about the lesion shown in a patient with stunting, osmotic diarrhea and anemia except:

Mucosa is not involved. ***Mucosa is not involved*** - This statement is **FALSE** and is the correct answer to this EXCEPT question. - The clinical presentation with **stunting, osmotic diarrhea, and anemia** clearly indicates **significant intestinal mucosal involvement** and malabsorption. - **Dermatitis herpetiformis** is the cutaneous manifestation of **celiac disease**, which by definition involves an immune-mediated injury to the **small intestinal mucosa** triggered by gluten ingestion. - The gastrointestinal symptoms described are direct evidence of mucosal damage, making this statement incorrect. *IgA antibody against epidermal transglutaminase* - This is TRUE. **Dermatitis herpetiformis** involves **IgA antibodies against epidermal transglutaminase (eTG)**, which deposit in the dermal papillae. - Patients also have IgA antibodies against tissue transglutaminase (tTG) due to the underlying celiac disease. - These antibodies are key diagnostic markers for both conditions. *Intense pruritic lesions* - This is TRUE. **Dermatitis herpetiformis** is classically characterized by **severely pruritic vesicular lesions** with a burning or stinging sensation. - The intense itching often leads to excoriations from scratching before vesicles are even visible. - Lesions typically occur on extensor surfaces (elbows, knees, buttocks, scalp). *Genes encoding DR2 present in all patients* - This statement is also FALSE, but less obviously so. **HLA-DQ2** (90-95%) and **HLA-DQ8** (5-10%) are the primary genetic associations with celiac disease and dermatitis herpetiformis. - If "DR2" refers to HLA-DR2, this is incorrect - DR2 is associated with other autoimmune conditions like multiple sclerosis, not celiac disease. - Even if this were meant to say DQ2, it would still be false as not 100% of patients carry these genes.

Question 1

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 2

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

Question 3

U-serrated pattern in direct immunofluorescence is seen in:

Accepted Answer

Epidermolysis bullosa acquisita

Answer

Bullous pemphigoid

Answer

Linear IgA disease

Answer

Dermatitis herpetiformis

Question 4

All are true about Dermatitis herpetiformis EXCEPT:

Accepted Answer

Lesions have epidermal bullae

Answer

The lesions are intensely itchy

Answer

IgA deposition in papillary tips

Answer

Associated with gluten enteropathy

Question 5

Intra-epithelial split is seen in which of the following conditions?

Accepted Answer

Pemphigus vulgaris

Answer

Epidermolysis bullosa

Answer

Bullous pemphigoid

Answer

All of the above

Question 6

A 12-year-old male presented with intensely itchy grouped vesicles on the buttock, trunk, and scalp. On exposure to wheat, they exaggerate. What is the diagnosis?

Accepted Answer

Dermatitis herpetiformis

Answer

Herpes simplex

Answer

Pemphigus vulgaris

Answer

Bullous impetigo

Question 7

Granular deposit of IgA at the dermoepidermal junction is seen in which of the following conditions?

Accepted Answer

Dermatitis herpetiformis

Answer

Pemphigus vulgaris

Answer

Bullous pemphigoid

Answer

Pemphigus foliaceus

Question 8

A 25-year-old office assistant in a multinational company was taking diclofenac sodium for low back ache for last few weeks. She presents with the following skin lesions. All are true about the image shown except:

Accepted Answer

$>30 \%$ BSA involvement in Stevens-Johnson syndrome

Answer

Hemorrhagic crusting of lips

Answer

Apoptotic keratinocytes

Answer

Systemic involvement leads to lung and kidney malfunction

Question 9

A patient presents with intensely pruritic vesicular lesions on extensor surfaces. What is the most likely diagnosis based on the clinical image?

Accepted Answer

Dermatitis herpetiformis

Answer

Psoriasis

Answer

Erythema marginatum

Answer

Lichen planus

Question 10

All are true about the lesion shown in a patient with stunting, osmotic diarrhea and anemia except:

Accepted Answer

Mucosa is not involved

Answer

IgA antibody against epidermal transglutaminase

Answer

Intense pruritic lesions

Answer

Genes encoding DR2 present in all patients

Blistering Diseases — MCQs

Blistering Diseases — MCQs

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