Epidermolysis Bullosa — MCQs
The main type of collagen in anchoring fibrils (component of dermoepidermal junction) is:
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?
Which of the following diseases of the skin is the most likely to be associated with partial anodontia?
Escharotomy is done in:
Which of the following is a feature of Ehlers-Danlos syndrome?
In an 8-day-old child with no history of consanguinity in the parents, the mother reports blisters and bleeding off the skin at the site of handling and pressure. There was a similar history in the previous child, which proved to be fatal. The diagnosis is
In congenital dystrophic variety of epidermolysis bullosa, mutation is seen in the gene coding for:
A 5-month-old child presented to the dermatology OPD with dryness along with white, fine scales on most parts of the body with sparing of face. The child was born at 39 weeks gestation by spontaneous vaginal delivery outside the hospital. On examination, fine, white scales were observed predominantly on the extensor surfaces of the limbs along with characteristic hyperlinearity of palms and accentuation of skin markings. Which of the following genes is most likely defective in the above condition:
Which of the following is NOT a typical feature of erythema multiforme?
The burrow in scabies is in
Epidermolysis Bullosa Indian Medical PG Practice Questions and MCQs
Question 1: The main type of collagen in anchoring fibrils (component of dermoepidermal junction) is:
- A. Type II
- B. Type IV
- C. Type VII (Correct Answer)
- D. Type III
Explanation: ***Type VII*** - **Type VII collagen** is the primary component of **anchoring fibrils**, which are essential structures that firmly attach the **dermal epidermal junction** to the underlying dermis. [1] - Mutations in the gene encoding **Type VII collagen** can lead to **dystrophic epidermolysis bullosa**, a condition characterized by fragile skin and blister formation due to poor dermal-epidermal adhesion. *Type II* - **Type II collagen** is predominantly found in **hyaline cartilage** and **elastic cartilage**, providing tensile strength and resilience within these tissues. - It is crucial for maintaining the structural integrity of **joints** and the respiratory tract, rather than dermal-epidermal adhesion. *Type IV* - **Type IV collagen** is a major component of **basement membranes**, forming a mesh-like network that provides structural support and filtration properties. - Although present at the **dermal epidermal junction** as part of the **basement membrane**, it does not primarily form the anchoring fibrils themselves. *Type III* - **Type III collagen** is widely distributed in **reticular fibers** in various tissues, including skin, blood vessels, and internal organs. - It provides elasticity and support to tissues, often co-localizing with **Type I collagen**, but does not form anchoring fibrils at the dermal-epidermal junction.
Question 2: 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?
- A. Pemphigus foliaceus
- B. Pemphigus Vulgaris
- C. Dermatitis herpetiformis
- D. Bullous Pemphigoid (Correct Answer)
Explanation: ***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.
Question 3: Which of the following diseases of the skin is the most likely to be associated with partial anodontia?
- A. erythema multiforme
- B. hereditary ectodermal dysplasia (Correct Answer)
- C. lichen planus
- D. keratosis follicularis
Explanation: ***Hereditary ectodermal dysplasia*** - This condition is characterized by abnormal development of **ectodermal structures**, including teeth, hair, nails, and sweat glands. - **Partial anodontia** (the congenital absence of some teeth) or even complete anodontia (**oligodontia**) is a hallmark clinical feature of ectodermal dysplasia due to impaired tooth bud formation. *Erythema multiforme* - This is an **acute, self-limiting inflammatory reaction** of the skin and mucous membranes, often triggered by infections (e.g., HSV) or medications. - It presents with characteristic **target lesions** and mucosal erosions but is not associated with dental developmental abnormalities like anodontia. *Lichen planus* - This is a **chronic inflammatory mucocutaneous disorder** affecting the skin, hair, nails, and mucous membranes, often presenting with **pruritic, purple, polygonal papules**. - It is an immune-mediated condition and does not involve developmental defects of teeth. *Keratosis follicularis* - Also known as **Darier disease**, this is an **autosomal dominant disorder** characterized by abnormal keratinization, leading to greasy, crusted papules primarily in seborrheic areas. - While it affects skin appendages, it is not directly linked to tooth agenesis or partial anodontia.
Question 4: Escharotomy is done in:
- A. Circumferential full thickness burns (Correct Answer)
- B. Superficial burns
- C. Burns in children
- D. Deep burns
Explanation: ***Circumferential full thickness burns*** - **Escharotomy** is a surgical incision made through the **eschar** (the burned, non-elastic tissue) to relieve pressure caused by **circumferential full-thickness burns**. - This procedure prevents **compartment syndrome**, preserves **distal circulation**, and facilitates **chest wall expansion** in truncal burns. *Superficial burns* - **Superficial burns** (first-degree) only affect the **epidermis** and do not form an **eschar** that restricts movement or circulation. - They are typically characterized by **redness** and **pain** and heal spontaneously without surgical intervention. *Burns in children* - While children can sustain **full-thickness burns** requiring **escharotomy**, the indication is the **type** and **circumferential nature** of the burn, not the patient's age itself. - The decision for escharotomy is based on physiological compromise, such as impaired circulation or respiration, regardless of age. *Deep burns* - **Deep partial-thickness** and **full-thickness burns** can develop **eschar**, but escharotomy is specifically indicated when the burn is **circumferential**, causing a tourniquet effect. - Non-circumferential deep burns, while requiring debridement and grafting, typically do not create the same constrictive pressure that necessitates an immediate escharotomy.
Question 5: Which of the following is a feature of Ehlers-Danlos syndrome?
- A. Achalasia
- B. Kyphoscoliosis
- C. Joint hypermobility (Correct Answer)
- D. Dermatosparaxis
Explanation: ***Pectus excavatum*** - This condition is characterized by a **depression of the sternum**, leading to a sunken chest appearance, and is least commonly associated with Ehlers-Danlos syndrome (EDS). - Other forms of EDS may present with more notable **joint hypermobility** and skin elasticity issues, rather than pectus excavatum [1]. *Kyphoscoliosis* - This is a common complication in certain types of Ehlers-Danlos syndrome, particularly affecting the spine's curvature [1]. - It is associated with **joint hypermobility** and can lead to significant postural abnormalities [1]. *Achalasia* - While achalasia can occur in EDS, it is not a typical or common association. - This esophageal motility disorder primarily affects **swallowing** due to a failure of the lower esophageal sphincter to relax. *Dermatosparaxis* - This form of EDS specifically features **skin fragility** and tearing with minimal trauma, indicating a significant association with the syndrome [1]. - It is characterized by **excessively fragile skin** and is directly linked to the pathogenic mechanisms of EDS [1].
Question 6: In an 8-day-old child with no history of consanguinity in the parents, the mother reports blisters and bleeding off the skin at the site of handling and pressure. There was a similar history in the previous child, which proved to be fatal. The diagnosis is
- A. Bullous pemphigoid
- B. Congenital syphilis
- C. Epidermolysis bullosa (Correct Answer)
- D. Letterer-Siwe disease (Langerhans cell histiocytosis)
Explanation: ***Epidermolysis bullosa*** - The presentation of **blisters and bleeding** at sites of trauma and handling in a neonate is pathognomonic for **epidermolysis bullosa (EB)**. - EB is a group of **inherited mechanobullous disorders** characterized by skin fragility; severe forms like **EB letalis (Herlitz type)** are **autosomal recessive** and often fatal in infancy. - The **positive family history** (previous fatal sibling) strongly suggests an inherited genetic disorder, consistent with EB. - The blisters occur at sites of **mechanical stress**, exactly as described in this case. *Bullous pemphigoid* - This is an **autoimmune blistering disease** typically affecting **older adults (>60 years)**, not neonates. - It is **not inherited** and does not present with a familial pattern. - Blisters are usually **tense and widespread**, not specifically triggered by handling or pressure. *Congenital syphilis* - Can cause **pemphigus syphiliticus** (bullous lesions on palms and soles) in the first few weeks of life. - However, it is an **infectious disease**, not inherited, so the **fatal outcome in a previous sibling** would not follow this pattern unless both were infected in utero. - Typically associated with other findings: **hepatosplenomegaly**, **rhinitis (snuffles)**, **skeletal abnormalities**, and positive maternal/infant serology. - Would be preventable with maternal screening and treatment. *Letterer-Siwe disease (Langerhans cell histiocytosis)* - Presents with **seborrheic-like or petechial rash**, hepatosplenomegaly, and systemic involvement. - Skin lesions are typically **papular, crusted, or purpuric**, not mechanically-induced blisters. - Does not characteristically present with **trauma-induced blistering** as the primary feature.
Question 7: In congenital dystrophic variety of epidermolysis bullosa, mutation is seen in the gene coding for:
- A. Laminin 4
- B. Keratin 14
- C. Collagen type 7 (Correct Answer)
- D. Alpha 6 integrin
Explanation: ***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.
Question 8: A 5-month-old child presented to the dermatology OPD with dryness along with white, fine scales on most parts of the body with sparing of face. The child was born at 39 weeks gestation by spontaneous vaginal delivery outside the hospital. On examination, fine, white scales were observed predominantly on the extensor surfaces of the limbs along with characteristic hyperlinearity of palms and accentuation of skin markings. Which of the following genes is most likely defective in the above condition:
- A. Filaggrin (Correct Answer)
- B. Desmoglein
- C. Plakophilin
- D. Plakoglobin
Explanation: ***Filaggrin*** - The clinical description of **fine, white scales**, **facial sparing**, **extensor surface involvement**, and **palmar hyperlinearity** is classic for **ichthyosis vulgaris**, the most common inherited disorder of keratinization. - **Filaggrin (FLG)** gene mutations are the most common cause of ichthyosis vulgaris, leading to impaired formation of the skin barrier and loss of natural moisturizing factor. - Typically presents between 3-12 months of age with xerosis and fine scaling. - Key features include **facial sparing**, **flexural sparing**, and **prominent palmar/plantar markings**. *Desmoglein* - **Desmoglein 1** and **Desmoglein 3** are desmosomal cadherins associated with **pemphigus** (autoimmune blistering disorder). - Desmoglein mutations do not cause ichthyotic scaling disorders. - The clinical presentation of fine scaling with facial sparing is not consistent with pemphigus or other desmoglein-related conditions. *Plakophilin* - **Plakophilin-1** mutations cause **ectodermal dysplasia-skin fragility syndrome**, characterized by skin erosions, blistering, alopecia, and nail dystrophy. - Does not present with generalized dry scaling or the pattern described in this case. - Skin fragility and erosions are the hallmark, not ichthyosis. *Plakoglobin* - **Plakoglobin (JUP gene)** mutations cause **Naxos disease**, featuring the triad of arrhythmogenic right ventricular cardiomyopathy, woolly hair, and palmoplantar keratoderma. - While palmoplantar involvement occurs, it is a focal keratoderma, not generalized fine scaling with facial sparing. - Cardiac manifestations are the most serious feature of this condition.
Question 9: Which of the following is NOT a typical feature of erythema multiforme?
- A. Triggered by HSV
- B. Mucosal involvement
- C. Target lesions
- D. Nikolsky sign (Correct Answer)
Explanation: ***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 10: The burrow in scabies is in
- A. S. corneum (Correct Answer)
- B. Malpighian layer
- C. S. germinatum
- D. S. granulosum
Explanation: ***S. corneum*** - The **burrow** created by the *Sarcoptes scabiei* mite is specifically found within the **stratum corneum** of the epidermis. - This superficial location allows the mite to feed on **keratinocytes** and deposit eggs, leading to the characteristic rash and intense itching. - The burrow appears as a **serpiginous tract** and is a pathognomonic finding in scabies. *Malpighian layer* - The **Malpighian layer** encompasses the **stratum basale** and **stratum spinosum**, which are deeper layers of the epidermis. - The scabies mite does not burrow into these deeper, metabolically active layers. *S. germinatum* - **Stratum germinativum** is another term for the **stratum basale**, the deepest epidermal layer responsible for cell division. - The scabies mite creates burrows at a much more superficial level in the stratum corneum. *S. granulosum* - The **stratum granulosum** lies between the stratum spinosum and stratum corneum. - While closer to the surface than the Malpighian layer, scabies burrows are specifically located in the more superficial **stratum corneum**, not the granulosum layer.
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