Blistering Diseases — MCQs

A 26-year-old girl at 31 weeks' gestation complains of a 4-week history of a pustular eruption that initially developed on the periumbilical skin and subsequently spread to involve the breasts, back, flexures, and proximal limbs, accompanied by cutaneous pain, fever, and malaise. On examination, the lesions were found to be pustules arranged in concentric rings, while on the breasts, there was coalescence of pustules forming lakes of pus. What is the treatment of choice in this case?

Q200

All of the following diseases cause intraepidermal bullae except:

Blistering Diseases Indian Medical PG Practice Questions and MCQs

Question 191: Which type of collagen is mutated in dystrophic epidermolysis bullosa?

A. Type I
B. Type II
C. Type IV
D. Type VII (Correct Answer)

Explanation: ***Type VII*** - **Type VII collagen** forms **anchoring fibrils** that connect the epidermis to the dermis at the dermal-epidermal junction, providing essential skin integrity. - Mutations in the gene encoding type VII collagen (**COL7A1**) lead to **dystrophic epidermolysis bullosa (DEB)**, characterized by severe blistering and skin fragility due to poor dermal-epidermal adhesion. - Note: Other forms of epidermolysis bullosa involve different proteins (e.g., keratins in EB simplex, laminin-332 in junctional EB). *Type I* - **Type I collagen** is the most abundant collagen in the body, found in **skin, bone, tendons, and ligaments**. - Mutations in type I collagen are primarily associated with conditions like **osteogenesis imperfecta**, causing brittle bones, not epidermolysis bullosa. *Type II* - **Type II collagen** is predominantly found in **cartilage**, making up the structural framework of hyaline cartilage. - Mutations in type II collagen are linked to **chondrodysplasias** and other skeletal disorders affecting cartilage development, not skin blistering. *Type IV* - **Type IV collagen** is a major component of **basement membranes**, providing structural support and filtration in various tissues. - Mutations in type IV collagen are associated with conditions like **Alport syndrome** (kidney/ear disease), not dystrophic epidermolysis bullosa.

Question 192: What is the antigen defect associated with Pemphigus Vulgaris?

A. Desmoglein-1
B. Desmoglein-3 (Correct Answer)
C. Desmocollin-3
D. Desmocollin-2

Explanation: ***Desmoglein-3*** - Pemphigus vulgaris is characterized by **autoantibodies** primarily targeting **desmoglein-3**, a component of **desmosomes**. - This autoimmune attack leads to **acantholysis** (loss of cell adhesion) within the deep epidermis, resulting in **flaccid blisters** that rupture easily. *Desmoglein-1* - Autoantibodies against **desmoglein-1** are primarily associated with **Pemphigus Foliaceus**, which causes more superficial blistering. - While Dsg1 antibodies can be present in Pemphigus vulgaris, Dsg3 antibodies are the **main culprits** responsible for the characteristic oral lesions and widespread deep epidermal blistering. *Desmocollin-3* - **Desmocollins** are another family of **cadherin proteins** found in desmosomes, but they are not the primary target in Pemphigus vulgaris. - Antibodies against desmocollins are less common and typically do not cause the classic clinical picture of pemphigus. *Desmocollin-2* - **Desmocollin-2** is found in **desmosomes**, but it is not the main target of autoantibodies in Pemphigus vulgaris. - The disease is specifically characterized by the disruption of cell-to-cell adhesion mediated by desmogleins.

Question 193: Which of the following statements is true regarding pemphigus vulgaris?

A. It primarily affects the dermal-epidermal junction.
B. It is a subepidermal blistering disease.
C. It is an intraepidermal blistering disease. (Correct Answer)
D. Antibodies are formed against basement membrane proteins.

Explanation: ***It is an intraepidermal blistering disease.*** - **Pemphigus vulgaris** is characterized by the formation of blisters *within the epidermis* due to the loss of cell-to-cell adhesion between **keratinocytes**. - This **acantholysis** results from autoantibodies targeting **desmosomes**, specifically **desmoglein 1 and 3**. *It is a subepidermal blistering disease.* - This statement is incorrect as it describes conditions like **bullous pemphigoid** or **dermatitis herpetiformis**, where blisters form *below* the epidermis. - In pemphigus vulgaris, the separation occurs *above* the basement membrane within the epidermal layer. *It primarily affects the dermal-epidermal junction.* - This is characteristic of **bullous pemphigoid** or **epidermolysis bullosa acquisita**, where the primary pathology involves the separation at the interface between the dermis and epidermis. - Pemphigus vulgaris directly affects the adhesion *within* the epidermis itself. *Antibodies are formed against basement membrane proteins.* - This is characteristic of **bullous pemphigoid**, where autoantibodies target components of the **basement membrane zone**, such as **BP180** and **BP230**. - In pemphigus vulgaris, the autoantibodies target **desmogleins** on the surface of keratinocytes, not basement membrane proteins.

Question 194: Pruritus is a feature of which of the following conditions?

A. Pemphigus foliaceous
B. Pemphigus vulgaris
C. Bullous pemphigoid (Correct Answer)
D. None of the options

Explanation: ***Bullous pemphigoid*** - **Pruritus**, often severe, is a common and early symptom of bullous pemphigoid, often preceding the appearance of skin lesions. - The disease involves autoantibodies against **hemidesmosomal proteins** (BPAG1, BPAG2), leading to subepidermal blister formation. *Pemphigus foliaceous* - This condition is characterized by **superficial blistering** and erosions, but **pruritus is typically mild or absent**. - Blisters form in the **granular layer of the epidermis** due to autoantibodies against desmoglein 1. *Pemphigus vulgaris* - Patients with pemphigus vulgaris present with **flaccid blisters and erosions**, mainly affecting the skin and mucous membranes, but **pruritus is not a prominent feature**. - The disease involves intraepidermal blistering caused by autoantibodies targeting **desmoglein 3 (and sometimes desmoglein 1)**. *None of the options* - This option is incorrect, as **pruritus is a characteristic symptom of bullous pemphigoid**.

Question 195: Acantholysis is not seen in:

A. Lichen planus (Correct Answer)
B. Dermatitis herpetiformis
C. Hailey-Hailey disease
D. Bullous pemphigoid

Explanation: ***Lichen planus*** - **Lichen planus** is a **non-blistering inflammatory dermatosis** where **acantholysis is completely absent** as it is not a blistering disorder. - Characterized by **acanthosis** (epidermal thickening), **hyperkeratosis**, **wedge-shaped hypergranulosis**, and a **band-like lymphocytic infiltrate** at the dermo-epidermal junction. - The pathology involves **basal cell liquefaction** and inflammation, not loss of keratinocyte cohesion. - **Most appropriate answer** as lichen planus is fundamentally a non-blistering condition, unlike the other options which are blistering diseases. *Bullous pemphigoid* - A **subepidermal bullous disease** where blister formation occurs *below* the epidermis at the **dermo-epidermal junction**. - Autoantibodies target **BP180 and BP230** antigens in **hemidesmosomes**, causing separation between epidermis and dermis. - **No acantholysis** is present as keratinocytes within the epidermis remain cohesive; the split is subepidermal. - Also a correct answer, but less optimal than lichen planus as it is still a blistering disease. *Dermatitis herpetiformis* - A **subepidermal blistering disease** associated with **celiac disease** and characterized by intensely pruritic papulovesicles. - Features **neutrophilic microabscesses** in dermal papillae and granular **IgA deposits** at the dermo-epidermal junction. - **No acantholysis** as blister formation is subepidermal due to immune complex deposition, not loss of keratinocyte adhesion. - Also technically correct, but lichen planus remains the best answer. *Hailey-Hailey disease* - **INCORRECT:** This condition is characterized by **suprabasal acantholysis**, making it a classic example where acantholysis IS present. - Also known as **familial benign chronic pemphigus**, caused by mutation in **ATP2C1 gene** affecting calcium regulation. - Leads to chronic, relapsing blistering and erosions in **intertriginous areas** (axillae, groin). - **Acantholysis is the defining histological feature**, producing a "dilapidated brick wall" appearance.

Question 196: A 40 year old male reported with recurrent episodes of oral ulcers, large areas of denuded skin and flaccid vesiculo-bullous eruptions. Which is the most important bedside investigation helpful in establishing the diagnosis -

A. Tzanck smear from the floor of bulla (Correct Answer)
B. Gram staining of blister fluid
C. Culture and sensitivity of blister fluid
D. Skin biopsy with immunofluorescence

Explanation: ***Tzanck smear from the floor of bulla*** - A Tzanck smear from the floor of a bulla will reveal **acantholytic cells** (rounded keratinocytes that have lost their intercellular connections), which are characteristic of pemphigus, consistent with recurrent oral ulcers, denuded skin, and flaccid vesiculobullous eruptions. - This **bedside test** provides a rapid diagnosis by demonstrating the cytological features of acantholysis, differentiating it from other blistering disorders. *Gram staining of blister fluid* - This test is primarily used to identify **bacterial infections** and would show the morphology and Gram-staining characteristics of any bacteria present. - It would not provide information about the **acantholysis** or autoimmune nature of the blistering condition described. *Culture and sensitivity of blister fluid* - This investigation identifies **specific bacterial pathogens** and their antibiotic susceptibilities, which is useful for treating bacterial infections. - It would not help in diagnosing **autoimmune blistering diseases** like pemphigus, where bacteria are not the primary cause of the lesions. *Skin biopsy with immunofluorescence* - While a **skin biopsy with direct immunofluorescence** is the gold standard for confirming pemphigus by detecting autoantibodies, it is an **invasive procedure** requiring laboratory processing and is not considered a rapid bedside investigation. - The question specifically asks for the "most important **bed-side investigation**" helpful in establishing the diagnosis rapidly.

Question 197: Nikolsky's sign is associated with which of the following conditions?

A. Herpes zoster
B. Bullous impetigo
C. All of the options
D. Pemphigus (Correct Answer)

Explanation: ***Pemphigus*** - **Nikolsky's sign** is the **most characteristic and consistent** clinical finding in pemphigus, where slight lateral pressure on seemingly normal skin near a blister or erosion causes the epidermis to shear off, forming a new blister or denudation. - This sign indicates **intraepidermal blistering** due to the loss of cell adhesion (acantholysis) caused by autoantibodies against desmoglein proteins. - **Pemphigus is the classic condition** associated with a positive Nikolsky's sign in medical literature and examinations. *Herpes zoster* - **Herpes zoster** (shingles) is characterized by painful, vesicular eruptions in a **dermatomal distribution**, which do **not exhibit Nikolsky's sign**. - The vesicles in herpes zoster are **intraepidermal** but result from viral cytopathic effect, not acantholysis, and the roof of the vesicle remains intact with lateral pressure. *Bullous impetigo* - Bullous impetigo is a superficial skin infection caused by *Staphylococcus aureus* that produces **large, flaccid blisters**. - While **Nikolsky's sign can occasionally be positive** in bullous impetigo (particularly in staphylococcal scalded skin syndrome), it is **much less consistent and prominent** compared to pemphigus. - The key distinction is that pemphigus remains the **most characteristic association** with Nikolsky's sign in clinical practice and examinations. *All of the options* - This option is incorrect because Nikolsky's sign is **most specifically and consistently associated with pemphigus**. - While bullous impetigo may occasionally show Nikolsky's sign, **pemphigus is the classic answer** for this clinical finding in medical examinations.

Question 198: Which of the following drug classes is commonly implicated in causing Stevens-Johnson syndrome?

A. Antibiotics (Correct Answer)
B. Corticosteroids
C. Antifungals
D. Proton pump inhibitors

Explanation: ***Antibiotics*** - **Antibiotics**, particularly **sulfonamides** (e.g., sulfamethoxazole-trimethoprim) and **beta-lactams** (e.g., penicillins, cephalosporins), are among the most common drug classes implicated in causing **Stevens-Johnson Syndrome (SJS)**. - SJS is a severe **idiosyncratic drug reaction**, and many antibiotics can trigger this immune-mediated response. - **Note:** Other major causative drug classes include **anticonvulsants** (carbamazepine, phenytoin, lamotrigine), **allopurinol**, and **NSAIDs**, but among the options listed, antibiotics are the most commonly implicated. *Corticosteroids* - **Corticosteroids** are typically used in the **treatment** of SJS to suppress the immune response and reduce inflammation, not to cause it. - While they have their own set of side effects, initiating SJS is not one of their known adverse reactions. *Antifungals* - Although some **antifungals** can cause adverse drug reactions, they are **not typically associated** with SJS compared to antibiotics, anticonvulsants, or allopurinol. - The risk of SJS with antifungal medications is generally very low. *Proton pump inhibitors* - **Proton pump inhibitors (PPIs)** are generally well-tolerated and are **rarely implicated** as a cause of SJS. - Their primary side effects are usually gastrointestinal and not severe dermatological reactions.

Question 199: A 26-year-old girl at 31 weeks' gestation complains of a 4-week history of a pustular eruption that initially developed on the periumbilical skin and subsequently spread to involve the breasts, back, flexures, and proximal limbs, accompanied by cutaneous pain, fever, and malaise. On examination, the lesions were found to be pustules arranged in concentric rings, while on the breasts, there was coalescence of pustules forming lakes of pus. What is the treatment of choice in this case?

A. Corticosteroids (Correct Answer)
B. Methotrexate
C. Topical itraconazole
D. Third generation cephalosporins

Explanation: ***Corticosteroids*** - The constellation of **pustular eruption** with **concentric rings**, especially in pregnancy, along with systemic symptoms like fever and malaise, is highly suggestive of **Pustular Psoriasis of Pregnancy (PPP)**, also known as **Impetigo Herpetiformis**. - **Systemic corticosteroids** (prednisolone) are the **first-line treatment** for this rare but severe dermatosis in pregnancy, aimed at controlling inflammation and preventing maternal and fetal complications. *Methotrexate* - **Methotrexate** is an **anti-metabolite** and **immunosuppressant** that is **teratogenic** and absolutely **contraindicated in pregnancy** due to its potential to cause severe birth defects and miscarriages. - While it can be used for severe psoriasis in non-pregnant individuals, its use in this pregnant patient is inappropriate and dangerous. *Topical itraconazole* - **Itraconazole** is an **antifungal medication** used to treat fungal infections. While typically used systemically, topical formulations exist for localized fungal infections. - The clinical presentation of widespread pustules arranged in **concentric rings** with systemic symptoms and **"lakes of pus"** in a pregnant woman is pathognomonic for **Impetigo Herpetiformis**, not a fungal infection, making this treatment inappropriate. *Third generation cephalosporins* - **Third-generation cephalosporins** are **antibiotics** primarily used to treat bacterial infections. - The distinctive pattern of **pustules in concentric rings**, the periumbilical onset, and progression to form **lakes of pus** in a pregnant woman represents an **inflammatory dermatosis** (Impetigo Herpetiformis), not a primary bacterial infection requiring antibiotics.

Question 200: All of the following diseases cause intraepidermal bullae except:

A. Miliaria rubra
B. Herpes gestationalis (Correct Answer)
C. Herpes zoster
D. Pemphigus

Explanation: ***Herpes gestationalis.*** - Herpes gestationalis is characterized by **urticarial papules** and vesicles, typically occurs in pregnancy, and does not form **intraepidermal bullae**. - This condition is linked more with **dermatitis herpetiformis** rather than with the intraepidermal blistering seen in the other options [2]. *Herpes zoster* - Herpes zoster causes **vesicular lesions** that are often grouped, presenting as painful **erythematous vesicles** along a dermatome. - The lesions can form intraepidermal bullae due to the **varicella-zoster virus** affecting the skin [1]. *Miliaria rubra* - Miliaria rubra, or **heat rash**, results from occluded sweat glands leading to **superficial vesicles or papules** in the epidermis. - The lesions may resemble blisters but are not true intraepidermal bullae and are prominent in hot, humid conditions. *Pemphigus* - Pemphigus is an autoimmune disorder causing **flaccid bullae** due to **acantholysis** in the epidermis, leading to intraepidermal bulla formation [3]. - It is characterized by **painful, fragile blisters** that rupture easily, differentiating it from other conditions listed [3]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Infectious Diseases, p. 366. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Skin, pp. 1172-1174. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Skin, pp. 1170-1172.

Practice by Chapter

Pemphigus Vulgaris

Practice Questions

Pemphigus Foliaceus

Practice Questions

Bullous Pemphigoid

Practice Questions

Cicatricial Pemphigoid

Practice Questions

Dermatitis Herpetiformis

Practice Questions

Epidermolysis Bullosa

Practice Questions

Linear IgA Bullous Dermatosis

Practice Questions

Pemphigoid Gestationis

Practice Questions

Drug-Induced Bullous Disorders

Practice Questions

Immunofluorescence in Bullous Diseases

Practice Questions

Management of Autoimmune Bullous Diseases

Practice Questions

Genetic Counseling in Inherited Blistering Diseases

Practice Questions

Want unlimited practice?

Get full access to all questions, explanations, and performance tracking.

Start For Free