Drug-Induced Bullous Disorders — MCQs
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
Which of the following is NOT a characteristic of pemphigus vulgaris?
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?
A patient on steroids develops sudden onset painful vesicles in T4 dermatome. Best initial treatment is:
Which drug is most commonly associated with causing fixed drug eruptions?
Which of the following is NOT associated with erythema nodosum?
A patient was recently started on Fluphenazine. A few weeks later, he developed tremors, rigidity, bradykinesia, and excessive salivation. The first line of management for this patient 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 drug classes is commonly implicated in causing Stevens-Johnson syndrome?
Acantholysis is seen in all except which of the following conditions?
Drug-Induced Bullous Disorders Indian Medical PG Practice Questions and MCQs
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
- A. Pemphigus vulgaris
- B. Bullous pemphigoid (Correct Answer)
- C. Lepra reaction
- D. Lichen planus
Explanation: ***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.
Question 2: Which of the following is NOT a characteristic of pemphigus vulgaris?
- A. Oral erosions
- B. Tzanck smear showing acantholytic cells
- C. Positive Nikolsky’s sign
- D. Subepidermal bulla (Correct Answer)
Explanation: ***Subepidermal bulla*** - Pemphigus vulgaris is characterized by **intraepidermal bullae** resulting from acantholysis (loss of cohesion between keratinocytes), not subepidermal bullae. - **Subepidermal bullae** are characteristic of conditions like **bullous pemphigoid**, where the split occurs below the epidermis. *Positive Nikolsky’s sign* - The **Nikolsky's sign** is positive in pemphigus vulgaris, indicating the fragility of the skin where gentle lateral pressure causes epidermal shearing. - This sign is a direct result of the **intraepidermal blistering** due to weakened cell-to-cell adhesion. *Oral erosions* - **Oral erosions** are a very common and often the initial manifestation of pemphigus vulgaris, frequently preceding skin lesions. - These painful erosions are persistent and heal slowly, sometimes making eating difficult. *Tzanck smear showing acantholytic cells* - A **Tzanck smear** from a fresh blister in pemphigus vulgaris typically reveals **acantholytic cells**, which are detached, rounded keratinocytes with basophilic cytoplasm. - The presence of acantholytic cells confirms the **loss of intercellular adhesion** within the epidermis, a hallmark of pemphigus.
Question 3: 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?
- A. Viral infection
- B. Drug induced (Correct Answer)
- C. Bacterial infection
- D. Idiopathic
Explanation: ***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.
Question 4: A patient on steroids develops sudden onset painful vesicles in T4 dermatome. Best initial treatment is:
- A. Oral Acyclovir
- B. Oral Valacyclovir
- C. Topical Acyclovir
- D. IV Acyclovir (Correct Answer)
Explanation: ***IV Acyclovir*** - Patients on **steroids** are considered **immunocompromised**, and a sudden onset of painful vesicles in a dermatomal distribution strongly suggests **herpes zoster (shingles)** [1]. - In immunocompromised patients, **intravenous acyclovir** is the preferred initial treatment due to better bioavailability and more rapid systemic drug levels, helping to prevent complications like **postherpetic neuralgia** or disseminated disease [1]. *Oral Acyclovir* - While oral acyclovir is used for herpes zoster, it is generally less effective in **immunocompromised patients** due to lower bioavailability compared to IV administration. - The slower onset of action and lower peak plasma concentrations may not be sufficient to control the viral infection rapidly in this high-risk group. *Oral Valacyclovir* - **Valacyclovir** is a prodrug of acyclovir with improved oral bioavailability, making it a good option for immunocompetent patients with herpes zoster. - However, for **immunocompromised patients**, particularly those on steroids, **IV acyclovir** is still superior due to the need for rapid and high systemic drug levels to prevent severe complications [1]. *Topical Acyclovir* - **Topical acyclovir** is primarily used for **herpes simplex labialis (cold sores)** and has very limited efficacy for systemic viral infections like **herpes zoster**. - It does not achieve adequate systemic concentrations to treat the underlying viral replication or prevent complications in dermatomal zoster, especially in an immunocompromised individual.
Question 5: Which drug is most commonly associated with causing fixed drug eruptions?
- A. Aminoglycoside
- B. Sulfonamide (Correct Answer)
- C. Erythromycin
- D. None of the options
Explanation: ***Sulfonamide*** - **Sulfonamides**, particularly **sulfamethoxazole-trimethoprim**, are frequently implicated in causing fixed drug eruptions. - A fixed drug eruption characteristically recurs at the **same cutaneous site** each time the offending drug is administered. *Aminoglycoside* - **Aminoglycosides** are broad-spectrum antibiotics known for potential **ototoxicity** and **nephrotoxicity**. - While they can cause various adverse reactions, fixed drug eruptions are **not a common association** with this drug class. *Erythromycin* - **Erythromycin** is a macrolide antibiotic primarily associated with **gastrointestinal side effects**, such as nausea and abdominal cramping. - Although drug eruptions can occur, fixed drug eruptions are **not typically linked** to erythromycin. *None of the options* - This option is incorrect because **sulfonamides** are well-documented causes of fixed drug eruptions. - Therefore, there is a specific drug class listed that is strongly associated with this condition.
Question 6: Which of the following is NOT associated with erythema nodosum?
- A. Leprosy
- B. Tuberculosis
- C. Pemphigus vulgaris (Correct Answer)
- D. Sarcoidosis
Explanation: ***Pemphigus vulgaris*** - Pemphigus vulgaris is an **autoimmune blistering disease** affecting the skin and mucous membranes, characterized by **flaccid bullae** that easily rupture. - Its pathogenesis involves autoantibodies against **desmogleins 1 and 3**, components of desmosomes, and it does not typically manifest with subcutaneous nodules or inflammation seen in erythema nodosum. *Leprosy* - Leprosy, particularly its **lepromatous forms**, can cause immunologically mediated inflammatory reactions known as **erythema nodosum leprosum**. - This presentation involves multiple tender, inflamed subcutaneous nodules, clinically and histologically resembling typical erythema nodosum. *Tuberculosis* - Tuberculosis is a well-known infectious cause of **erythema nodosum**, especially in young adults and children. - The skin lesions often indicate a **hypersensitivity reaction** to the mycobacterial antigens. *Sarcoidosis* - Sarcoidosis is a systemic granulomatous disease, and **erythema nodosum** is a common **cutaneous manifestation**, particularly in acute sarcoidosis. - When associated with bilateral hilar lymphadenopathy and arthralgia, it forms **Löfgren's syndrome**, a specific presentation of sarcoidosis.
Question 7: A patient was recently started on Fluphenazine. A few weeks later, he developed tremors, rigidity, bradykinesia, and excessive salivation. The first line of management for this patient is
- A. Pramipexole
- B. Trihexyphenidyl (Correct Answer)
- C. Selegiline
- D. Amantadine
Explanation: ***Trihexyphenidyl*** - The patient is exhibiting symptoms of **drug-induced parkinsonism** (tremors, rigidity, bradykinesia, excessive salivation) due to **fluphenazine**, an antipsychotic. - **Anticholinergic medications** like trihexyphenidyl are the **first-line treatment** for drug-induced parkinsonism as they help restore the balance between dopamine and acetylcholine. *Pramipexole* - This is a **dopamine agonist** primarily used in the management of idiopathic **Parkinson's disease** and restless legs syndrome. - While it addresses dopamine deficiency, it is not the first-line treatment for **drug-induced parkinsonism**, where the issue is often dopamine receptor blockade rather than primary dopamine depletion. *Selegiline* - **Selegiline** is a selective **MAO-B inhibitor** used to treat idiopathic Parkinson's disease by preventing the breakdown of dopamine in the brain. - It is not the most appropriate first-line choice for **drug-induced parkinsonism** as it does not directly counteract the dopamine receptor blockade caused by antipsychotics. *Amantadine* - **Amantadine** is an antiviral drug with mild **dopaminergic properties** that can be used to treat **Parkinson's disease** and drug-induced extrapyramidal symptoms, particularly dyskinesia. - While sometimes used, it is generally considered **second-line** to anticholinergics for the acute management of **drug-induced parkinsonism**.
Question 8: 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 9: 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 10: Acantholysis is seen in all except which of the following conditions?
- A. Pemphigus vulgaris
- B. Darier's disease
- C. Bullous pemphigoid (Correct Answer)
- D. SSSS
Explanation: ***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.
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