Blistering Diseases Practice Questions

Q: Which of the following vesico-bullous disorders will exhibit the direct immunofluorescence shown below?

Bullous pemphigoid. ***Bullous pemphigoid*** - The direct immunofluorescence image shows a characteristic **linear deposition of IgG and/or C3 along the basement membrane zone (BMZ)**, which is pathognomonic for bullous pemphigoid. - This pattern reflects the targeting of hemidesmosomal proteins like BP180 and BP230, leading to a subepidermal blister. *Pemphigus vulgaris* - Direct immunofluorescence in pemphigus vulgaris would show a **"chicken wire" or intercellular reticular pattern of IgG and C3 deposition** within the epidermis, indicating antibody binding to desmoglein 1 and/or 3. - This pattern signifies acantholysis within the epidermis, leading to intraepidermal blistering. *Pemphigus vegetans* - This is a variant of pemphigus vulgaris, so it would exhibit the same **intercellular "chicken wire" pattern of IgG and C3 deposition** in the epidermis, reflecting antibodies against desmogleins. - The distinctive feature of pemphigus vegetans is the development of verrucous vegetations, primarily in intertriginous areas, not a different DIF pattern. *Pemphigus foliaceus* - Direct immunofluorescence in pemphigus foliaceus also shows an **intercellular "chicken wire" pattern of IgG deposition**, but typically limited to the **superficial epidermis**, specifically targeting desmoglein 1. - Unlike bullous pemphigoid, it does not show linear deposition along the basement membrane zone.

Q: Identify the lesion shown below.

Stevens-Johnson syndrome. ***Stevens-Johnson syndrome*** - The image shows a child with widespread **erosions and crusted lesions** primarily on the face, including peri-oral and ocular involvement, which is highly characteristic of **Stevens-Johnson syndrome (SJS)**. - SJS is a severe, acute mucocutaneous reaction typically triggered by drugs, characterized by **epidermal detachment** and involvement of at least two mucous membranes. *Geographic tongue* - **Geographic tongue** (benign migratory glossitis) is a benign condition characterized by irregular, erythematous patches on the tongue with white borders due to **loss of filiform papillae**. - It affects only the tongue and does not involve widespread skin and mucosal lesions as seen in the image. *Black hairy tongue* - **Black hairy tongue** is a harmless condition where the papillae on the tongue become elongated and discolored, often due to poor oral hygiene, smoking, or antibiotic use. - It is confined to the dorsum of the tongue and presents as a furry, dark overgrowth, not the erosive and crusted lesions seen in the image. *Acrodermatitis enteropathica* - **Acrodermatitis enteropathica** is a rare, inherited or acquired **zinc deficiency** disorder presenting with a characteristic triad of **dermatitis**, **diarrhea**, and **alopecia**. - The dermatitis typically affects acral and periorificial areas, but the lesions are usually erythematous, vesicular, bullous, or pustular, and classically scaly, rather than the extensive erosions and crusting seen in the image.

Q: What is the diagnosis based on the image shown below?

Mycosis fungoides. ***Mycosis fungoides*** - The image exhibits **Pautrier microabscesses**, which are collections of atypical lymphocytes within the epidermis, a hallmark of mycosis fungoides. - There is also a **band-like infiltrate of atypical lymphocytes** in the upper dermis, characteristic of this cutaneous T-cell lymphoma. *Pemphigus* - Pemphigus is characterized by **intraepidermal blistering due to acantholysis** (loss of cohesion between keratinocytes), which is not seen in this image. - Histology would show separated keratinocytes, often with a "tombstone" appearance of basal cells, and **no Pautrier microabscesses**. *Dermal leishmaniasis* - Dermal leishmaniasis is caused by _Leishmania_ parasites and typically presents with a **dermal infiltrate rich in macrophages** containing intracellular amastigotes. - The image does not show these features; instead, it shows an atypical lymphoid infiltrate. *Psoriasis* - Psoriasis typically shows **acanthosis (epidermal hyperplasia)** with elongation of rete ridges, **parakeratosis**, and **Munro microabscesses** (neutrophilic collections in the stratum corneum). - While there is some epidermal thickening, the distinct Pautrier microabscesses and atypical lymphoid infiltrate are not features of psoriasis.

Q: A 60-year-old female presents with eczematous itching lesions. Biopsy revealed a subepidermal cleft with Direct Immunofluorescence showing Linear C3 & IgG deposition along the basement membrane zone. What is the likely diagnosis?

Bullous Pemphigoid. ***Bullous Pemphigoid*** - The presence of **eczematous itching lesions**, a **subepidermal cleft**, and **linear C3 and IgG deposition along the basement membrane zone** on direct immunofluorescence (DIF) are classic diagnostic features of Bullous Pemphigoid. - This autoimmune blistering disease typically affects older individuals and is characterized by antibodies targeting components of the **hemidesmosomes**, specifically BP180 and BP230. *Pemphigus foliaceus* - This condition involves **intraepidermal blistering**, specifically within the granular layer, rather than a subepidermal cleft. - DIF in Pemphigus foliaceus shows **intercellular IgG deposition** in the epidermis, not linear deposition along the basement membrane zone. *Pemphigus Vulgaris* - Pemphigus Vulgaris is characterized by **intraepidermal blistering** above the basal cell layer (**suprabasal clefting**), leading to fragile bullae that rupture easily. - DIF typically reveals **intercellular IgG and C3 deposition** in a "chicken wire" pattern throughout the epidermis, which differs from the linear pattern seen in this case. *Dermatitis herpetiformis* - While Dermatitis herpetiformis is also an autoimmune blistering disease with itching lesions, its characteristic DIF finding is **granular IgA deposition** in the dermal papillae, not linear C3 and IgG at the basement membrane zone. - Histopathology in Dermatitis herpetiformis shows **subepidermal vesicles** with neutrophil infiltration in the dermal papillae, but the direct immunofluorescence pattern is distinct.

Q: A 4-year-old boy presents with multiple vesicles and bullae on an erythematous base. The lesions primarily affect his elbows, knees, and buttocks, with some oral involvement. His mother reports that he gets similar lesions with minor trauma. Skin biopsy shows subepidermal separation with neutrophilic infiltrate. Direct immunofluorescence shows linear IgA deposits at the basement membrane. Which of the following is the most appropriate treatment?

Dapsone. ***Dapsone*** - The clinical presentation (vesicles and bullae on **elbows, knees, buttocks, oral involvement**, trauma-induced lesions), along with **subepidermal separation with neutrophilic infiltrate** and **linear IgA deposits** on direct immunofluorescence, is highly characteristic of **Linear IgA bullous dermatosis (LABD)**. - **Dapsone** is considered the first-line treatment for LABD due to its efficacy in reducing IgA deposition and clearing lesions. *Oral steroids* - While oral steroids can be used for acute flares or severe cases of bullous diseases, they are generally not the **first-line chronic treatment** for LABD due to significant side effects. - They also may not be as effective as dapsone in targeting the specific IgA-mediated pathology of LABD. *Azathioprine* - **Azathioprine** is an immunosuppressant often used in autoimmune bullous diseases that are **refractory to initial treatments**, or as a **steroid-sparing agent**. - It is not typically considered the first-line therapy for LABD, especially when dapsone is highly effective. *Cyclosporine* - **Cyclosporine** is another potent immunosuppressant that might be used in severe or refractory cases of autoimmune bullous diseases, but it is not the primary treatment for LABD. - Its use is limited by potential **renal toxicity** and other significant side effects.

Q: In congenital dystrophic variety of epidermolysis bullosa, mutation is seen in the gene coding for:

Collagen type 7. ***Correct: Collagen type 7*** - **Dystrophic epidermolysis bullosa** is characterized by defects in **collagen type 7**, which forms anchoring fibrils that connect the epidermis to the underlying dermal tissue. - Mutations in the gene *COL7A1* lead to fragile skin that **blisters easily** in the **dermo-epidermal junction** below the lamina densa (sublamina densa level). - This distinguishes it from other EB subtypes by its **sub-basement membrane zone** blistering. *Incorrect: Laminin 4* - Mutations in **laminin 332** (formerly laminin 5), not laminin 4, are associated with **junctional epidermolysis bullosa**, a different subtype. - Junctional EB primarily affects the **lamina lucida** within the dermo-epidermal junction. *Incorrect: Keratin 14* - Mutations in **keratin 5** and **keratin 14** are responsible for **epidermolysis bullosa simplex**, which involves blistering within the **basal layer of the epidermis**. - In this form, blisters occur *intraepidermally* above the basement membrane zone. *Incorrect: Alpha 6 integrin* - Mutations in **alpha 6 beta 4 integrin** subunits are also associated with **junctional epidermolysis bullosa**, specifically affecting the assembly of **hemidesmosomes**. - These defects lead to blistering within the **lamina lucida**, similar to laminin 332 mutations.

Q: All of the following statements about Stevens-Johnson Syndrome are true EXCEPT:

Systemic steroids are proven first-line therapy. ***Systemic steroids are proven first-line therapy*** - While systemic steroids are often used in the management of SJS/TEN, their efficacy as a **proven first-line therapy** remains controversial and is not universally accepted. - Many studies have shown conflicting results regarding benefits, and some evidence even suggests potential harms, particularly with high doses in early stages. *Early withdrawal of causative drug improves prognosis* - This statement is **true** because prompt identification and cessation of the offending drug are crucial for halting disease progression and improving patient outcomes in SJS. - Continued exposure to the causative agent can exacerbate the immune response, leading to more widespread epidermal necrosis and an increased risk of complications and mortality. *Nikolsky sign may be positive* - This statement is **true**. The **Nikolsky sign**, characterized by the detachment of the epidermis from the dermis with gentle lateral pressure, is a characteristic finding in SJS. - This sign indicates epidermal fragility and is a clinical manifestation of the widespread keratinocyte necrosis occurring in SJS. *SCORTEN score predicts mortality* - This statement is **true**. The **SCORTEN score** is a validated prognostic tool used to estimate the risk of death in patients with SJS and toxic epidermal necrolysis (TEN). - It assesses several clinical and laboratory parameters within the first 24-48 hours of admission to help guide management and allocate intensive care resources.

Q: A patient with acute history of blistering and denudation involving >30% BSA along with erosions of the lips with hemorrhagic crusting and other mucosa for few days. What is the most common triggering factor?

Drug induced. ***Drug induced*** - **Toxic epidermal necrolysis (TEN)**, characterized by blistering and denudation of >30% body surface area and mucosal involvement, is most commonly triggered by **drugs**, such as sulfonamides, antiepileptics, allopurinol, and NSAIDs. - The rapid onset and severe presentation are highly suggestive of an adverse drug reaction. *Viral infection* - While viruses can trigger some mucocutaneous reactions, severe widespread necrosis and denudation like in TEN are not typically **direct viral effects**. - **Herpes simplex virus (HSV)** can cause erythema multiforme, which is less severe and extensive than TEN. *Idiopathic* - While some cases of severe cutaneous adverse reactions can be idiopathic, the vast majority of **TEN cases have an identifiable trigger**, with drugs being the leading cause. - Attributing it to an unknown cause would be less precise given the common association with medications. *Bacterial infection* - Bacterial infections, such as **Staphylococcal scalded skin syndrome (SSSS)**, can cause blistering and desquamation, but it primarily affects children and involves a superficial epidermal split, rather than the full-thickness necrosis seen in TEN. - SSSS typically spares the **mucous membranes**, unlike the prominent mucosal involvement described in the patient.

Q: A diabetic patient presents with painful hemorrhagic bullae on legs. Investigations show raised creatinine. Most likely diagnosis:

Calciphylaxis. ***Calciphylaxis*** - Characterized by **painful hemorrhagic bullae** and ulcers, often on the lower extremities, especially in patients with **end-stage renal disease** or **diabetes**. - **Raised creatinine** indicates kidney dysfunction, which is a significant risk factor for calciphylaxis due to abnormalities in calcium and phosphorus metabolism. *PCT (Porphyria Cutanea Tarda)* - Presents with **fragile skin, blistering, hyperpigmentation**, and **hirsutism** on sun-exposed areas, typically triggered by iron overload or hepatitis C [1]. - While it can cause bullae, the painful hemorrhagic nature and association with severe kidney disease are less typical features compared to calciphylaxis. 'Uraemic porphyria' in renal failure presents similarly but is due to impaired porphyrin elimination [1]. *Diabetic bullae* - Also known as **bullosis diabeticorum**, these are **tense, non-inflammatory, painless blisters** that appear on acral (hands, feet) or non-acral skin. - Unlike the painful hemorrhagic bullae seen here, diabetic bullae are typically non-hemorrhagic and not usually associated with advanced renal failure as a direct cause. *Bullous pemphigoid* - An **autoimmune subepidermal blistering disease** that usually presents as large, **tense bullae** on an erythematous base on the trunk and flexural areas. - Although it presents with bullae, it is typically **pruritic** rather than painful and hemorrhagic, and its association with elevated creatinine is not a primary diagnostic feature.

Q: Which of the following is NOT a typical feature of erythema multiforme?

Nikolsky sign. ***Nikolsky sign*** - The **Nikolsky sign** involves the detachment of the superficial epidermis from the basal layer when lateral pressure is applied to seemingly uninvolved skin, indicative of severe blistering diseases like **pemphigus vulgaris** or **toxic epidermal necrolysis (TEN)**, but not typically **erythema multiforme (EM)**. - While EM can involve blistering, the characteristic mechanism of epidermal detachment that produces a positive Nikolsky sign is not a feature of its pathogenesis. *Triggered by HSV* - **Herpes simplex virus (HSV) infection** is the most common precipitating factor for **erythema multiforme**, particularly in its recurrent form (erythema multiforme minor). - An immune response to viral antigens deposited in the skin is thought to drive the characteristic skin lesions. *Mucosal involvement* - **Mucosal involvement** is a common feature, especially in **erythema multiforme major**, affecting the oral cavity, eyes, and/or anogenital region. - This can manifest as painful erosions and ulcers, contributing to significant morbidity. *Target lesions* - **Target lesions**, with their characteristic concentric rings of color (erythematous outer ring, pale edematous middle ring, and dusky or vesicular center), are the **hallmark skin lesion** of erythema multiforme. - These lesions are typically fixed and symmetrically distributed, often on the extremities.

Question 1

Which of the following vesico-bullous disorders will exhibit the direct immunofluorescence shown below?

Accepted Answer

Bullous pemphigoid

Answer

Pemphigus vulgaris

Answer

Pemphigus vegetans

Answer

Pemphigus foliaceus

Question 2

Identify the lesion shown below.

Accepted Answer

Stevens-Johnson syndrome

Answer

Geographic tongue

Answer

Black hairy tongue

Answer

Acrodermatitis enteropathica

Question 3

What is the diagnosis based on the image shown below?

Accepted Answer

Mycosis fungoides

Answer

Pemphigus

Answer

Dermal leishmaniasis

Answer

Psoriasis

Question 4

A 60-year-old female presents with eczematous itching lesions. Biopsy revealed a subepidermal cleft with Direct Immunofluorescence showing Linear C3 & IgG deposition along the basement membrane zone. What is the likely diagnosis?

Accepted Answer

Bullous Pemphigoid

Answer

Pemphigus foliaceus

Answer

Pemphigus Vulgaris

Answer

Dermatitis herpetiformis

Question 5

A 4-year-old boy presents with multiple vesicles and bullae on an erythematous base. The lesions primarily affect his elbows, knees, and buttocks, with some oral involvement. His mother reports that he gets similar lesions with minor trauma. Skin biopsy shows subepidermal separation with neutrophilic infiltrate. Direct immunofluorescence shows linear IgA deposits at the basement membrane. Which of the following is the most appropriate treatment?

Accepted Answer

Dapsone

Answer

Oral steroids

Answer

Azathioprine

Answer

Cyclosporine

Question 6

In congenital dystrophic variety of epidermolysis bullosa, mutation is seen in the gene coding for:

Accepted Answer

Collagen type 7

Answer

Laminin 4

Answer

Keratin 14

Answer

Alpha 6 integrin

Question 7

All of the following statements about Stevens-Johnson Syndrome are true EXCEPT:

Accepted Answer

Systemic steroids are proven first-line therapy

Answer

Early withdrawal of causative drug improves prognosis

Answer

Nikolsky sign may be positive

Answer

SCORTEN score predicts mortality

Question 8

A patient with acute history of blistering and denudation involving >30% BSA along with erosions of the lips with hemorrhagic crusting and other mucosa for few days. What is the most common triggering factor?

Accepted Answer

Drug induced

Answer

Viral infection

Answer

Idiopathic

Answer

Bacterial infection

Question 9

A diabetic patient presents with painful hemorrhagic bullae on legs. Investigations show raised creatinine. Most likely diagnosis:

Accepted Answer

Calciphylaxis

Answer

PCT

Answer

Diabetic bullae

Answer

Bullous pemphigoid

Question 10

Which of the following is NOT a typical feature of erythema multiforme?

Accepted Answer

Nikolsky sign

Answer

Triggered by HSV

Answer

Mucosal involvement

Answer

Target lesions

Blistering Diseases — MCQs

Blistering Diseases — MCQs

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