Blistering Diseases Practice Questions

Q: A 85-year-old female developed multiple blisters on the trunk and thighs. Nikolsky's sign is negative. The lesions came on and off. The most probable diagnosis is

Bullous pemphigoid. ***Bullous pemphigoid*** - The presence of **multiple tense blisters** on the trunk and thighs in an 85-year-old female, coupled with a **negative Nikolsky's sign**, is highly characteristic of bullous pemphigoid. - This condition tends to wax and wane, causing the lesions to "come on and off," and is more common in the **elderly**. *Lichen planus* - This condition presents with **pruritic, polygonal, purple, planar papules and plaques**, not blisters. - It does not typically involve the formation of **blisters** as the primary lesion nor does it involve a negative Nikolsky's sign. *Pemphigus vulgaris* - Characterized by **flaccid blisters** that rupture easily, leading to erosions, and a **positive Nikolsky's sign**. - This is in contrast to the **tense blisters** and **negative Nikolsky's sign** described in the patient. *Lepra reaction* - Refers to **acute inflammatory episodes** occurring in patients with leprosy, often presenting as **erythematous nodules** or plaques. - It does not typically involve the formation of **blisters** on the trunk and thighs in an elderly patient without a prior diagnosis of leprosy.

Q: A 40-year-old male developed persistent oral ulcers, followed by multiple flaccid bullae on the trunk and extremities. Direct immunofluorescence examination of a skin biopsy showed intercellular IgG deposits in the epidermis. What is the most probable diagnosis?

Pemphigus vulgaris. ***Pemphigus vulgaris*** - The presence of **persistent oral ulcers** followed by **flaccid bullae** on the trunk and extremities are classic clinical features. - **Direct immunofluorescence (DIF)** showing **intercellular IgG deposits** in the epidermis confirms the diagnosis, indicating antibodies against **desmogleins** within the desmosomes. *Bullous Pemphigoid* - Characterized by **tense bullae**, unlike the flaccid bullae seen in this case, and typically affects older individuals. - DIF would show **linear IgG and C3 deposits along the dermal-epidermal junction**, not intercellular epidermal deposits. *Bullous Lupus erythematosus* - This condition is rare and presents with **tense bullae** and other systemic manifestations of lupus erythematosus. - DIF usually shows granular or linear deposits of **IgG, IgA, or C3 at the dermal-epidermal junction**, sometimes in a "lupus band" pattern, but not intercellular epidermal IgG. *Epidermolysis bullosa acquisita* - Presents with skin fragility and **blisters in response to trauma**, particularly on acral surfaces, with features resembling **dystrophic epidermolysis bullosa**. - DIF reveals **linear IgG or IgA deposits along the dermal-epidermal junction** targeting type VII collagen, distinguishing it from pemphigus vulgaris.

Q: A 50-year-old female presents with blisters and erosions on the skin and mucous membranes, most commonly inside the mouth. What is the most likely diagnosis?

Pemphigus vulgaris. ***Pemphigus vulgaris*** - This condition is characterized by **flaccid blisters** that easily rupture, leading to painful erosions, often starting in the **oral mucosa** (50-70% of cases). - It is an **autoimmune disease** with antibodies against **desmoglein 3 (mucous membranes) and desmoglein 1 (skin)**, causing **intraepidermal blistering**. - **Nikolsky sign positive** - lateral pressure causes sloughing of skin. *Dermatitis herpetiformis* - This presents with intensely **pruritic (itchy) grouped vesicles** on extensor surfaces (elbows, knees, buttocks), not flaccid blisters with oral involvement. - It is strongly associated with **celiac disease** and characterized by **IgA deposition in the dermal papillae**. *Bullous pemphigoid* - Presents with **tense blisters** on an erythematous base, typically in **elderly patients (>60 years)**. - **Oral mucosa usually spared** or involved late in the disease course. - Involves autoantibodies against **hemidesmosomal proteins (BP180 and BP230)**, leading to **subepidermal blistering**. *Erythema multiforme* - Characterized by **target lesions** and can involve mucous membranes, but typically presents acutely with symmetrical distribution. - Often triggered by **infections (HSV) or medications**, not an autoimmune blistering disease. - Lacks the chronic, progressive oral erosions typical of pemphigus vulgaris.

Q: Acantholysis is seen in all except which of the following conditions?

Bullous pemphigoid. ***Bullous pemphigoid*** - This condition involves **subepidermal blistering**, meaning the separation of the epidermis from the dermis, which occurs *below* the **basal cell layer**. - **Acantholysis**, the loss of cohesion between keratinocytes *within* the epidermis, does not occur in bullous pemphigoid, making it the correct answer. *Pemphigus vulgaris* - This is an **autoimmune blistering disease** characterized by the presence of autoantibodies against **desmoglein 3** (and often desmoglein 1). - This leads to intraepidermal blistering caused by **acantholysis**, the primary pathophysiological event. *Darier's disease* - This is an **autosomal dominant genodermatosis** characterized by abnormal keratinization and acantholysis. - Due to defects in **ATP2A2** (encoding SERCA2), there is impaired calcium handling in keratinocytes, leading to premature desmosomal degradation and **acantholysis**. *SSSS (Staphylococcal Scalded Skin Syndrome)* - Caused by **exfoliative toxins** (ETA and ETB) produced by *Staphylococcus aureus* that target **desmoglein 1**. - The cleavage of desmoglein 1 results in superficial **intraepidermal blistering** due to **acantholysis** in the granular layer of the epidermis.

Q: A patient presents with a history of bullae involving more than 30% of the body surface area, along with rashes all over the body and erosions of the lips and other mucosa, for a few days. What could be the potential triggering factor for this condition?

Drug induced. ***Correct: Drug induced*** - The severe presentation with widespread **bullae** covering over 30% of the body surface area, extensive rashes, and **mucosal erosions** (lips) is highly suggestive of **Toxic Epidermal Necrolysis (TEN)**. - TEN is most commonly **drug-induced**, often triggered by medications like **antibiotics** (sulfonamides, penicillins), **anticonvulsants** (carbamazepine, phenytoin, lamotrigine), **NSAIDs**, and **allopurinol**. - The combination of extensive skin detachment (>30% BSA), mucosal involvement, and acute onset strongly points to a drug-induced etiology. *Incorrect: Viral infection* - While some viral infections can cause rashes and mucocutaneous lesions, they typically do not lead to such widespread **epidermal detachment** and severe **mucosal erosions** affecting over 30% BSA, as seen in TEN. - Viral exanthems (e.g., measles, herpes) are generally milder and have different morphology compared to the full-thickness epidermal necrosis seen in this condition. *Incorrect: Bacterial infection* - Bacterial skin infections can cause **bullous impetigo** or **staphylococcal scalded skin syndrome (SSSS)**, but SSSS typically spares the mucous membranes and involves superficial epidermal splitting (not full-thickness necrosis). - The extent and severity of the lesions, including widespread **mucosal involvement**, are more consistent with a systemic hypersensitivity reaction rather than a localized or superficial bacterial infection. *Incorrect: Idiopathic* - Although the cause can sometimes be undetermined, the pattern of severe symptoms described—especially with extensive **skin sloughing** and **mucosal involvement**—points strongly to a known etiology. - TEN has a well-established association with drug triggers in **80-95% of cases**, making a truly idiopathic cause unlikely in the absence of thorough drug history evaluation.

Q: Nikolsky's sign is seen in all of the following, except:

Bullous pemphigoid. ***Bullous pemphigoid*** - **Nikolsky's sign** is typically **negative** in bullous pemphigoid because the blistering occurs in the **subepidermal region**, leading to a strong dermo-epidermal adhesion that resists tangential pressure. - The blisters in bullous pemphigoid are generally **tense** and do not rupture easily, reflecting the deep separation plane. *Mucous membrane pemphigoid* - **Nikolsky's sign** is typically **negative** in mucous membrane pemphigoid (also known as cicatricial pemphigoid) because it is also a **subepidermal blistering disorder**. - Like bullous pemphigoid, the cleavage occurs below the epidermis, preserving the integrity of the epidermal layer and maintaining resistance to lateral shearing forces. - The blisters are typically tense rather than flaccid, reflecting the deeper plane of separation. *Toxic epidermal necrolysis* - **Nikolsky's sign** is **positive** in toxic epidermal necrolysis (TEN) due to the extensive **full-thickness epidermal necrosis** and detachment, which is the hallmark of the condition. - Gentle tangential pressure causes the epidermis to easily shear off, revealing large areas of denuded dermis. *Scalded skin syndrome* - **Nikolsky's sign** is **positive** in scalded skin syndrome (SSSS) because the **exfoliative toxins** produced by *Staphylococcus aureus* cleave **desmoglein 1** in the superficial epidermis. - This cleavage leads to rapid and widespread **intraepidermal detachment** and flaccid blistering, making the skin highly susceptible to shearing.

Q: A 85-year-old woman has large blistering lesions on the abdomen and thighs that come and go without therapy, and Nikolsky sign is negative. Which of the following is the most likely diagnosis?

bullous pemphigoid. ***Bullous pemphigoid*** - This condition typically affects **elderly individuals** with large, tense bullae that often resolve spontaneously and a negative **Nikolsky sign**. - **Immunofluorescence** shows IgG and C3 deposits along the **dermal-epidermal junction**. *Pemphigus vulgaris* - Characterized by **flaccid bullae** that rupture easily and a **positive Nikolsky sign**, which is not seen here. - Patients are usually younger and involvement of **mucous membranes** is common. *Dermatitis herpetiformis* - This condition presents with **pruritic papulovesicular lesions** arranged in a herpetiform pattern. - It is associated with **celiac disease** and responds to a gluten-free diet. *Herpes gestationis* - Also known as **pemphigoid gestationis**, this rare autoimmune blistering disease occurs during **pregnancy or postpartum**. - It presents with **urticarial plaques and bullae**, primarily on the abdomen and extremities, but is not relevant to an 85-year-old woman.

Q: 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

Epidermolysis bullosa. ***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.

Q: Which of the following HLA types is associated with dermatitis herpetiformis?

HLA B8. ***HLA B8*** - **HLA B8** is associated with **dermatitis herpetiformis**, an autoimmune blistering skin condition characterized by intensely pruritic vesicles. - HLA B8 is part of the extended haplotype (HLA-A1, B8, DR3, DQ2) commonly found in patients with dermatitis herpetiformis. - The **strongest association** is actually with **HLA-DQ2** and **HLA-DQ8** (found in ~95% of DH patients), as DH is closely linked with **celiac disease** and shares the same HLA associations. - Among the options listed, **HLA B8** is the one with a recognized association. *HLA A5* - **HLA A5** has no established association with **dermatitis herpetiformis**. - It is not considered a genetic risk factor for this condition. *HLA A28* - **HLA A28** has no significant association with **dermatitis herpetiformis**. - It does not confer increased susceptibility to this autoimmune blistering disorder. *HLA B27* - **HLA B27** is strongly associated with **seronegative spondyloarthropathies** including **ankylosing spondylitis**, **reactive arthritis**, and **psoriatic arthritis**. - It is not associated with dermatitis herpetiformis or other autoimmune blistering diseases.

Question 1

A 85-year-old female developed multiple blisters on the trunk and thighs. Nikolsky's sign is negative. The lesions came on and off. The most probable diagnosis is

Accepted Answer

Bullous pemphigoid

Answer

Pemphigus vulgaris

Answer

Lepra reaction

Answer

Lichen planus

Question 2

A 40-year-old male developed persistent oral ulcers, followed by multiple flaccid bullae on the trunk and extremities. Direct immunofluorescence examination of a skin biopsy showed intercellular IgG deposits in the epidermis. What is the most probable diagnosis?

Accepted Answer

Pemphigus vulgaris

Answer

Bullous Pemphigoid

Answer

Bullous Lupus erythematosus

Answer

Epidermolysis bullosa acquisita

Question 3

A 50-year-old female presents with blisters and erosions on the skin and mucous membranes, most commonly inside the mouth. What is the most likely diagnosis?

Accepted Answer

Pemphigus vulgaris

Answer

Dermatitis herpetiformis

Answer

Bullous pemphigoid

Answer

Erythema multiforme

Question 4

Acantholysis is seen in all except which of the following conditions?

Accepted Answer

Bullous pemphigoid

Answer

Pemphigus vulgaris

Answer

Darier's disease

Answer

SSSS

Question 5

Which of the following statements about mucous membrane pemphigoid is correct?

Accepted Answer

Oral lesions may be found in any region, especially in the attached gingiva; ocular lesions can lead to blindness if untreated.

Answer

It presents as multiple, painful ulcers preceded by bullae which form below the epithelium at the basement membrane.

Answer

None of the options.

Answer

It primarily affects young adults and children, with peak incidence in the 2nd to 3rd decade of life.

Question 6

A patient presents with a history of bullae involving more than 30% of the body surface area, along with rashes all over the body and erosions of the lips and other mucosa, for a few days. What could be the potential triggering factor for this condition?

Accepted Answer

Drug induced

Answer

Viral infection

Answer

Bacterial infection

Answer

Idiopathic

Question 7

Nikolsky's sign is seen in all of the following, except:

Accepted Answer

Bullous pemphigoid

Answer

Toxic epidermal necrolysis

Answer

Scalded skin syndrome

Answer

Mucous membrane pemphigoid

Question 8

A 85-year-old woman has large blistering lesions on the abdomen and thighs that come and go without therapy, and Nikolsky sign is negative. Which of the following is the most likely diagnosis?

Accepted Answer

bullous pemphigoid

Answer

pemphigus vulgaris

Answer

dermatitis herpetiformis

Answer

herpes gestationis

Question 9

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

Accepted Answer

Epidermolysis bullosa

Answer

Bullous pemphigoid

Answer

Congenital syphilis

Answer

Letterer-Siwe disease (Langerhans cell histiocytosis)

Question 10

Which of the following HLA types is associated with dermatitis herpetiformis?

Accepted Answer

HLA B8

Answer

HLA A5

Answer

HLA A28

Answer

HLA B27

Blistering Diseases — MCQs

Blistering Diseases — MCQs

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