Acne Vulgaris: Pathophysiology — MCQs
A patient presented with oily skin and acne formation primarily on the face. Multiple enlarged glands were noted on examination. What is the etiopathogenesis of the disease process?
Skin biopsy shows psoriasiform hyperplasia with neutrophilic microabscesses in stratum corneum. Most likely diagnosis?
An organism produces cutaneous disease (malignant pustule or eschar) at the site of inoculation in handlers of animal skins. Most likely organism is:
Which of the following is the causative agent for acne fulminans?
Benzoyl peroxide acts in acne vulgaris by
Statement 1 - A 59-year-old patient presents with flaccid bullae. Histopathology shows a suprabasal acantholytic split. Statement 2 - The row of tombstones appearance is diagnostic of Pemphigus vulgaris.
An 18-year-old man has facial and upper back lesions that have waxed and waned for the past 6 years. On physical examination, there are 0.3- to 0.9-cm comedones, erythematous papules, nodules, and pustules most numerous on the lower face and posterior upper trunk. Other family members have been affected by this condition at a similar age. The lesions worsen during a 5-day cruise to the Adriatic. Which of the following organisms is most likely to play a key role in the pathogenesis of these lesions?
Benzoyl peroxide acts in acne vulgaris by:
A 40 year old woman presents with a 2 year history of erythematous papulopustular lesions on convexities of the face. There is a background of erythema & telangiectasia. The most likely diagnosis is –
Which of the following are treatment options for acne vulgaris?
Acne Vulgaris: Pathophysiology Indian Medical PG Practice Questions and MCQs
Question 1: A patient presented with oily skin and acne formation primarily on the face. Multiple enlarged glands were noted on examination. What is the etiopathogenesis of the disease process?
- A. Septal deviation of nose
- B. Mucous gland hypertrophy
- C. Sweat gland hypertrophy
- D. Sebaceous gland hypertrophy (Correct Answer)
Explanation: ***Sebaceous gland hypertrophy*** - **Oily skin (seborrhea)** and **acne formation** are directly linked to increased activity and size of the sebaceous glands. - Hypertrophied sebaceous glands produce excessive **sebum**, which clogs pores and creates a favorable environment for **Cutibacterium acnes** (formerly *Propionibacterium acnes*), leading to acne. *Septal deviation of nose* - **Septal deviation** is a structural abnormality within the nose, primarily affecting breathing and potentially leading to snoring or nosebleeds. - It has no direct etiopathogenic link to **acne** or **oily skin**. *Mucous gland hypertrophy* - **Mucous gland hypertrophy** typically occurs in conditions like chronic bronchitis, leading to increased mucus production in the respiratory tract. - It is unrelated to **skin oiliness** or **acne vulgaris**. *Sweat gland hypertrophy* - **Sweat gland hypertrophy** would primarily result in excessive sweating (**hyperhidrosis**). - While sweat glands contribute to skin moisture, their hypertrophy does not directly cause the **oily appearance** or **acne breakouts** described.
Question 2: Skin biopsy shows psoriasiform hyperplasia with neutrophilic microabscesses in stratum corneum. Most likely diagnosis?
- A. Psoriasis (Correct Answer)
- B. Seborrheic dermatitis
- C. Pityriasis rosea
- D. Lichen planus
Explanation: ***Psoriasis*** - **Psoriasiform hyperplasia**, characterized by regular epidermal acanthosis and elongated rete ridges, is a classic histological feature of psoriasis. - The presence of **neutrophilic microabscesses (Munro microabscesses)** in the stratum corneum is a pathognomonic finding for psoriasis. *Seborrheic dermatitis* - Histologically, seborrheic dermatitis typically shows **irregular acanthosis** with parakeratosis and a **perivascular lymphocytic infiltrate**, but not regular psoriasiform hyperplasia or Munro microabscesses. - There may be *spongiosis* and neutrophils in the stratum corneum, but not the distinct microabscesses seen in psoriasis. *Pityriasis rosea* - Pityriasis rosea histology often reveals **focal parakeratosis**, **spongiosis**, and a **perivascular lymphocytic infiltrate** with extravasated red blood cells. - It does not demonstrate the characteristic regular psoriasiform hyperplasia or neutrophilic microabscesses of psoriasis. *Lichen planus* - Lichen planus is characterized by a **"sawtooth" rete ridge pattern**, a **band-like lymphocytic infiltrate** at the dermo-epidermal junction, and **colloid bodies (Civatte bodies)**. - It does not exhibit psoriasiform hyperplasia or neutrophilic microabscesses in the stratum corneum.
Question 3: An organism produces cutaneous disease (malignant pustule or eschar) at the site of inoculation in handlers of animal skins. Most likely organism is:
- A. Neisseria meningitidis
- B. Bacillus anthracis (Correct Answer)
- C. Pseudomonas aeruginosa
- D. Cryptococcus neoformans
Explanation: ***Bacillus anthracis*** - This description is classic for **cutaneous anthrax**, characterized by a **malignant pustule** or **eschar** that develops at the site of inoculation. - The context of handling **animal skins** (e.g., wool-sorter's disease) is a key epidemiological clue for _Bacillus anthracis_ infection. *Neisseria meningitidis* - Primarily causes **meningitis** and **meningococcemia**, involving a petechial or purpuric rash, not a single eschar or malignant pustule. - There is no direct association with handling animal skins. *Pseudomonas aeruginosa* - This bacterium is often associated with **opportunistic infections** in immunocompromised individuals, burn patients, or those with indwelling medical devices. - While it can cause skin lesions (e.g., **ecthyma gangrenosum**), these are distinct from the anthrax eschar and are not linked to animal skin exposure. *Cryptococcus neoformans* - A **fungus** that primarily causes **cryptococcal meningitis** or pulmonary infections, especially in immunocompromised individuals. - Skin manifestations, when they occur, are typically papules, nodules, or ulcers, not the classic **cutaneous anthrax eschar**.
Question 4: Which of the following is the causative agent for acne fulminans?
- A. Staphylococcus aureus
- B. Malassezia furfur
- C. Propionibacterium acnes (Cutibacterium acnes) (Correct Answer)
- D. Streptococcus pyogenes
Explanation: ***Propionibacterium acnes (Cutibacterium acnes)*** - **Acne fulminans** is a severe, ulcerative form of acne that is considered an **autoinflammatory syndrome** rather than a simple bacterial infection - While the exact etiology remains unclear, ***Cutibacterium acnes*** (formerly *Propionibacterium acnes*) plays a significant role in the pathophysiology - It is believed that acne fulminans may result from a **hypersensitivity reaction to *C. acnes* antigens** or an exaggerated immune response to the bacterium - *C. acnes* is the **most relevant microorganism** associated with all forms of acne, including acne vulgaris and severe variants like acne fulminans - Treatment often includes systemic corticosteroids (to control inflammation) combined with isotretinoin *Staphylococcus aureus* - *Staphylococcus aureus* causes **bacterial skin infections** such as folliculitis, impetigo, furuncles, and cellulitis - While secondary bacterial superinfection with *S. aureus* can complicate acne lesions, it is **not the primary organism** associated with acne fulminans *Malassezia furfur* - *Malassezia furfur* (now classified as *Malassezia globosa* or *M. restricta*) is a **yeast** that causes **pityriasis versicolor** and **Malassezia folliculitis** (also called fungal acne or pityrosporum folliculitis) - It is **not involved** in the pathogenesis of acne vulgaris or acne fulminans *Streptococcus pyogenes* - *Streptococcus pyogenes* is a common cause of **streptococcal infections** including pharyngitis, impetigo, erysipelas, and cellulitis - It is **not associated** with acne or acne fulminans pathogenesis
Question 5: Benzoyl peroxide acts in acne vulgaris by
- A. Acts as oxidizing agent
- B. Decreased sebum production
- C. Reduces epithelial proliferation
- D. Decreasing bacterial count (Correct Answer)
Explanation: **Decreasing bacterial count** - Benzoyl peroxide is a potent **antimicrobial agent** that works by releasing oxygen free radicals, which are toxic to the anaerobic *Propionibacterium acnes* (now *Cutibacterium acnes*) bacteria. - This reduction in bacterial load directly addresses one of the primary pathogenic factors in **acne vulgaris**. *Acts as oxidizing agent* - While benzyl peroxide does act as an oxidizing agent, this description is a mechanism of how it works, not its primary therapeutic effect in acne. - The oxidative action primarily destroys bacterial cell walls and proteins, leading to its **bactericidal effect**. *Decreased sebum production* - Retinoids (e.g., isotretinoin) are primarily responsible for **decreasing sebum production**, which is a key factor in acne pathogenesis. - Benzoyl peroxide does not significantly alter the activity of sebaceous glands. *Reduces epithelial proliferation* - Topical and oral retinoids (e.g., tretinoin, isotretinoin) function by modulating **epithelial keratinization** and proliferation, preventing the formation of comedones. - Benzoyl peroxide does not directly target epidermal cell turnover but rather exhibits a mild **comedolytic effect** indirectly.
Question 6: Statement 1 - A 59-year-old patient presents with flaccid bullae. Histopathology shows a suprabasal acantholytic split. Statement 2 - The row of tombstones appearance is diagnostic of Pemphigus vulgaris.
- A. Statements 1 & 2 are correct, 2 is not explaining 1 (Correct Answer)
- B. Statements 1 and 2 are correct and 2 is the correct explanation for 1
- C. Statements 1 and 2 are incorrect
- D. Statement 1 is incorrect
Explanation: ***Correct: Statements 1 & 2 are correct, 2 is not explaining 1*** **Analysis of Statement 1:** - A 59-year-old patient with **flaccid bullae** and **suprabasal acantholytic split** on histopathology is the classic presentation of **Pemphigus vulgaris** - The flaccid (easily ruptured) nature of bullae distinguishes it from tense bullae seen in bullous pemphigoid - The suprabasal location of the split (just above the basal layer) with acantholysis (loss of cell-to-cell adhesion) is pathognomonic - **Statement 1 is CORRECT** ✓ **Analysis of Statement 2:** - The **"row of tombstones" or "tombstone appearance"** is indeed a diagnostic histopathological feature of Pemphigus vulgaris - This appearance results from basal keratinocytes remaining attached to the basement membrane while suprabasal cells separate due to acantholysis - The intact basal cells standing upright resemble a row of tombstones - **Statement 2 is CORRECT** ✓ **Does Statement 2 explain Statement 1?** - Statement 2 describes a **histopathological appearance** (tombstone pattern) that is a **consequence** of the suprabasal split - However, it does NOT explain the **underlying cause** of the flaccid bullae or the suprabasal split - The true explanation involves **IgG autoantibodies against desmoglein 3 (and desmoglein 1)**, which attack intercellular adhesion structures (desmosomes), causing **acantholysis** - Therefore, **Statement 2 does NOT explain Statement 1** ✗ *Incorrect: Statement 2 is the correct explanation for Statement 1* - While both statements describe features of Pemphigus vulgaris, the tombstone appearance is a descriptive finding, not an explanatory mechanism *Incorrect: Statements 1 and 2 are incorrect* - Both statements are medically accurate descriptions of Pemphigus vulgaris features *Incorrect: Statement 1 is incorrect* - Statement 1 correctly describes the cardinal clinical and histopathological features of Pemphigus vulgaris
Question 7: An 18-year-old man has facial and upper back lesions that have waxed and waned for the past 6 years. On physical examination, there are 0.3- to 0.9-cm comedones, erythematous papules, nodules, and pustules most numerous on the lower face and posterior upper trunk. Other family members have been affected by this condition at a similar age. The lesions worsen during a 5-day cruise to the Adriatic. Which of the following organisms is most likely to play a key role in the pathogenesis of these lesions?
- A. Propionibacterium acnes (Correct Answer)
- B. Herpes simplex virus type 1
- C. Group A β-hemolytic streptococcus
- D. Mycobacterium leprae
Explanation: ***Propionibacterium acnes*** (now *Cutibacterium acnes*) - The presence of **comedones, papules, nodules, and pustules** on the face and upper back in an 18-year-old is classic for **acne vulgaris**. - **_P. acnes_** is a commensal bacterium that proliferates in clogged hair follicles, contributing to inflammation and lesion formation in acne due to its lipolytic activity and immune-activating properties. *Herpes simplex virus type 1* - **HSV-1** typically causes **oral herpes (cold sores)** or **genital herpes**, characterized by painful vesicles and ulcers. - The described lesions (comedones, papules, nodules, pustules) are not characteristic of HSV-1 infection. *Group A β-hemolytic streptococcus* - **Group A Strep** causes infections like **pharyngitis (strep throat)**, **impetigo**, or **cellulitis**, which are typically acute and rapidly spreading. - Its presence is not associated with chronic, polymorphic lesions characteristic of acne. *Mycobacterium leprae* - **_M. leprae_** is the causative agent of **leprosy**, presenting with skin lesions, nerve damage, and other systemic effects. - The skin lesions of leprosy are typically macules, papules, or nodules with sensory loss, not the comedones and pustules seen in acne.
Question 8: Benzoyl peroxide acts in acne vulgaris by:
- A. Decreasing bacterial count (Correct Answer)
- B. Reduces sebum production
- C. Acts as a keratolytic agent
- D. Increases epithelial turnover
Explanation: ***Decreasing bacterial count*** - **Benzoyl peroxide** is a highly effective topical treatment for acne primarily due to its potent **antimicrobial activity** against *Cutibacterium acnes*, the bacterium implicated in acne pathogenesis. - It works by releasing **free radicals** that disrupt bacterial cell membranes and metabolism, thereby reducing the bacterial load in follicles. *Reduces sebum production* - While sebaceous gland activity is critical in acne, benzoyl peroxide does **not directly reduce sebum production**; retinoids like isotretinoin are known for this effect. - Its primary action is focused on combating bacteria and mildly promoting desquamation rather than affecting **lipid synthesis**. *Acts as a keratolytic agent* - Benzoyl peroxide does possess some **keratolytic activity**, aiding in the shedding of dead skin cells and preventing pore blockage. - However, its keratolytic action is **less pronounced** compared to agents like salicylic acid or tretinoin, and it is not its primary mechanism of action. *Increases epithelial turnover* - While benzoyl peroxide does promote a mild increase in **epithelial cell turnover**, helping to clear clogged pores, it is not its main mechanism of action or defining characteristic. - **Topical retinoids** (e.g., tretinoin, adapalene) are far more effective and primarily used to normalize follicular keratinization and increase cell turnover.
Question 9: A 40 year old woman presents with a 2 year history of erythematous papulopustular lesions on convexities of the face. There is a background of erythema & telangiectasia. The most likely diagnosis is –
- A. Polymorphic light eruption
- B. Acne vulgaris
- C. Acne rosacea (Correct Answer)
- D. SLE
Explanation: ***Acne rosacea*** - This condition presents with **erythematous papulopustular lesions**, background **erythema**, and **telangiectasias** predominantly on the convexities of the face, which is a classic presentation for rosacea. - The absence of **comedones** (blackheads/whiteheads) helps differentiate it from acne vulgaris. *Polymorphic light eruption* - This is a recurring skin rash triggered by **sun exposure**, presenting as itchy papules, plaques, or vesicles, usually appearing a few hours after exposure. - Unlike rosacea, it does not typically feature permanent facial erythema or telangiectasias and is more directly linked to UV exposure episodes. *Acne vulgaris* - While it features papules and pustules, **acne vulgaris** is characterized by the presence of **comedones** (blackheads and whiteheads), which are not described in the patient's presentation. - It also does not typically involve the prominent background erythema and telangiectasias seen in rosacea. *SLE* - Systemic lupus erythematosus (SLE) can cause a **malar or 'butterfly' rash** across the nose and cheeks, but it is typically a fixed erythema, sometimes with scaling, and does not usually involve papulopustular lesions or telangiectasias as a primary feature. - SLE often has systemic symptoms (e.g., joint pain, fatigue) that are not mentioned, and skin lesions can be photosensitive but are not typically pustular.
Question 10: Which of the following are treatment options for acne vulgaris?
- A. Isotretinoin
- B. All of the options (Correct Answer)
- C. Topical erythromycin
- D. Oral Minocycline
Explanation: ***All of the options*** - All listed options (Isotretinoin, Topical erythromycin, and Oral Minocycline) are well-established and commonly used **treatment options for acne vulgaris**, depending on the severity and type of acne. - The choice of treatment often follows a stepped approach, starting with topical agents for mild to moderate acne and progressing to oral medications like antibiotics or isotretinoin for more severe or resistant cases. *Isotretinoin* - **Isotretinoin** is a powerful oral retinoid primarily used for **severe, recalcitrant nodular acne** that has not responded to other treatments. - It works by reducing sebum production, follicular hyperkeratinization, inflammation, and the growth of *P. acnes*. *Topical erythromycin* - **Topical erythromycin** is an **antibiotic** used to treat mild to moderate inflammatory acne by reducing the growth of *Cutibacterium acnes* (formerly *Propionibacterium acnes*) and decreasing inflammation. - It is often combined with other topical agents like benzoyl peroxide to minimize the development of **antibiotic resistance**. *Oral Minocycline* - **Oral minocycline** is a **tetracycline antibiotic** used for moderate to severe inflammatory acne. - It reduces bacterial populations on the skin and exhibits **anti-inflammatory properties**, making it effective for widespread or deeper lesions.
Want unlimited practice?
Get full access to all questions, explanations, and performance tracking.
Start For Free