Molluscum Contagiosum — MCQs
Koebner's phenomenon is seen in all of the following except:
Koebner's phenomenon is seen in all except
Ivermectin is indicated in the treatment of:
Which cytopathic effect would confirm molluscum contagiosum virus infection?
A child presents with grouped vesicles on the lips. What is the bedside investigation that you would like to do?
A woman presents with lesions on the inner thighs and peri-anal region. They are nodular, 4-6 mm in size and appear pale. The histopathological image shows multiple intracytoplasmic inclusion bodies consistent with Henderson-Patterson bodies. The diagnosis is:
Which of the following statements about molluscum contagiosum is FALSE?
A young man presented with painful vesicular lesions distributed along a dermatomal pattern on one side of his body. What is the likely diagnosis?
Multinucleated giant cell on Tzanck smear is not seen in?
Which of the following is not a poxvirus?
Molluscum Contagiosum Indian Medical PG Practice Questions and MCQs
Question 1: Koebner's phenomenon is seen in all of the following except:
- A. Darier's disease
- B. Molluscum contagiosum
- C. Scleromyxedema
- D. Erythema multiforme (Correct Answer)
Explanation: ***Erythema multiforme*** - **Erythema multiforme** is an acute hypersensitivity reaction that does **NOT** typically demonstrate the Koebner phenomenon. - Unlike chronic papulosquamous disorders, EM lesions arise from immunologic triggers (infections, drugs) rather than trauma-induced spread. - The characteristic **target lesions** develop in response to antigenic stimuli, not mechanical trauma. *Darier's disease* - **Darier's disease** (keratosis follicularis) is an autosomal dominant disorder that exhibits the Koebner phenomenon. - New keratotic papules develop at sites of trauma, scratching, or friction. - This trauma-induced lesion development is a **key clinical feature** of the disease. *Molluscum contagiosum* - **Molluscum contagiosum** demonstrates the Koebner phenomenon through **autoinoculation**. - Scratching can cause viral spread, resulting in **linear arrangements of lesions** along scratch marks. - This is a classic example of trauma-induced spread in viral skin infections. *Scleromyxedema* - **Scleromyxedema** (generalized lichen myxedematosus) can exhibit the Koebner phenomenon. - New papules may develop at sites of trauma in some cases. - While less commonly emphasized than in psoriasis or lichen planus, Koebnerization has been reported in this condition.
Question 2: Koebner's phenomenon is seen in all except
- A. Psoriasis
- B. Warts
- C. Tinea corporis (Correct Answer)
- D. Molluscum contagiosum
Explanation: ***Tinea corporis*** - **Koebner's phenomenon**, also known as the isomorphic response, is the appearance of skin lesions characteristic of a **pre-existing dermatosis** at sites of **trauma** to previously uninvolved skin. - **Tinea corporis**, a **superficial fungal infection**, does NOT exhibit true Koebner's phenomenon. - Its spread occurs through **direct fungal contact or autoinoculation**, not through an isomorphic response to non-specific trauma. *Psoriasis* - **Psoriasis** is the **classic example** of Koebner's phenomenon. - New psoriatic plaques can appear at sites of **skin trauma** such as scratches, surgical scars, burns, or tattoos within **10-20 days** of injury. - This occurs in approximately **25-50%** of psoriasis patients. *Warts* - **Warts** (verruca vulgaris), caused by **human papillomavirus (HPV)**, can show what is sometimes called **pseudo-Koebner's phenomenon**. - Trauma facilitates **viral inoculation** and seeding of HPV into the skin, leading to new wart formation along scratch lines. - However, this is technically **viral spread through trauma**, not a true isomorphic response of a pre-existing dermatosis. *Molluscum contagiosum* - **Molluscum contagiosum** can similarly demonstrate **pseudo-Koebner's phenomenon**. - Scratching spreads the **molluscum contagiosum virus** to adjacent areas, creating linear arrays of lesions. - Like warts, this represents **direct viral inoculation** rather than true isomorphic response, but is often grouped with Koebner's phenomenon in clinical practice.
Question 3: Ivermectin is indicated in the treatment of:
- A. Scabies (Correct Answer)
- B. Dermatophytosis
- C. Tuberculosis
- D. Syphilis
Explanation: ***Scabies*** - **Ivermectin** is an effective oral antiparasitic agent used to treat **scabies**, particularly in cases of widespread infestation, crusted scabies, or when topical treatments fail. - It acts by paralyzing and killing the **Sarcoptes scabiei mites** responsible for the infestation. *Dermatophytosis* - **Dermatophytosis** (ringworm) is a **fungal infection** of the skin, hair, or nails. - It is typically treated with **antifungal medications** (e.g., azoles, terbinafine), not ivermectin. *Tuberculosis* - **Tuberculosis** is a bacterial infection caused by **Mycobacterium tuberculosis**, primarily affecting the lungs. - Treatment involves a multi-drug regimen of **antibiotics** (e.g., rifampin, isoniazid), for several months. *Syphilis* - **Syphilis** is a sexually transmitted bacterial infection caused by **Treponema pallidum**. - The primary treatment for syphilis is **penicillin**, usually administered via injection.
Question 4: Which cytopathic effect would confirm molluscum contagiosum virus infection?
- A. Cowdry type B inclusions
- B. Owl's eye inclusions
- C. Negri bodies
- D. Henderson-Paterson bodies (Correct Answer)
Explanation: ***Henderson-Paterson bodies*** - These are characteristic **large, eosinophilic intracytoplasmic inclusion bodies** seen in keratinocytes infected with the **molluscum contagiosum virus**. - Their presence confirms a diagnosis of molluscum contagiosum upon histological examination. *Cowdry type B inclusions* - These are **intracytoplasmic inclusion bodies** associated with **adenovirus** and **poliovirus** infections. - They are not characteristic of molluscum contagiosum virus, which forms distinct Henderson-Paterson bodies. *Owl's eye inclusions* - These are large, **intranuclear inclusion bodies with a clear halo** surrounding a dense central core, classically seen in cells infected with **cytomegalovirus (CMV)**. - They are distinct from the cytoplasmic inclusions of molluscum contagiosum. *Negri bodies* - These are **eosinophilic cytoplasmic inclusions** found in the cytoplasm of hippocampal pyramidal cells and Purkinje cells of the cerebellum, pathognomonic for **rabies virus infection**. - They are associated with a different viral family and are distinct from molluscum contagiosum inclusions.
Question 5: A child presents with grouped vesicles on the lips. What is the bedside investigation that you would like to do?
- A. Wood's lamp
- B. Slit skin smear
- C. Tzanck smear (Correct Answer)
- D. KOH
Explanation: ***Tzanck smear*** - A **Tzanck smear** is a rapid bedside test that can identify **multinucleated giant cells**, which are seen in herpes simplex virus infections. - The presence of **grouped vesicles on the lips** is highly suggestive of **herpes labialis** (HSV-1), which is primarily a **clinical diagnosis**. - Among the options provided, Tzanck smear is the only relevant bedside investigation, though it has **limited sensitivity and specificity** and **cannot distinguish between HSV and VZV**. - In modern practice, **PCR or direct immunofluorescence** are preferred when laboratory confirmation is needed, but Tzanck smear remains a low-cost option in resource-limited settings. *Wood's lamp* - A Wood's lamp uses **ultraviolet light** to detect certain fungal or bacterial infections by revealing characteristic fluorescence. - It is useful for conditions like **tinea capitis** (green fluorescence) and **erythrasma** (coral-red fluorescence), but has no role in diagnosing viral vesicular lesions. *Slit skin smear* - A **slit skin smear** is used to detect **acid-fast bacilli** in the diagnosis of **leprosy**. - It is not indicated for vesicular lesions and is irrelevant to herpes simplex infection. *KOH* - A **KOH (potassium hydroxide) mount** is used to diagnose **fungal infections** by dissolving keratinocytes and revealing fungal hyphae or spores. - It has no utility in diagnosing viral infections such as herpes simplex.
Question 6: A woman presents with lesions on the inner thighs and peri-anal region. They are nodular, 4-6 mm in size and appear pale. The histopathological image shows multiple intracytoplasmic inclusion bodies consistent with Henderson-Patterson bodies. The diagnosis is:
- A. Trichodysplasia spinulosa
- B. Molluscum contagiosum (Correct Answer)
- C. Condyloma acuminata
- D. Donovanosis
Explanation: ***Molluscum contagiosum*** - The clinical presentation of **nodular, pale lesions** in the inner thighs and peri-anal region, combined with histopathology showing **Henderson-Patterson bodies** (large eosinophilic intracytoplasmic inclusions), is pathognomonic for molluscum contagiosum. - Henderson-Patterson bodies represent viral factories within infected keratinocytes, a key diagnostic feature of this **poxvirus** infection. *Trichodysplasia spinulosa* - This condition is characterized by **follicular papules** with prominent keratin spines, typically occurring on the face, and is associated with the **Trichodysplasia spinulosa-associated polyomavirus**. - It does not present with Henderson-Patterson bodies or the typical nodular lesions seen in molluscum contagiosum. *Condyloma acuminata* - These are **genital warts** caused by the **human papillomavirus (HPV)**, presenting as verrucous or cauliflower-like growths. - Histologically, they show **koilocytic atypia** (vacuolated cells with nuclear abnormalities), not Henderson-Patterson bodies. *Donovanosis* - Also known as **granuloma inguinale**, this is a chronic, progressive, ulcerative granulomatous disease caused by **Klebsiella granulomatis**. - Histopathology reveals **Donovan bodies** (intracellular bacteria within macrophages), which are distinct from Henderson-Patterson bodies and the clinical presentation of nodular lesions.
Question 7: Which of the following statements about molluscum contagiosum is FALSE?
- A. Lesions contain characteristic inclusion bodies
- B. Autoinoculation can spread the infection to new sites
- C. It is caused by a poxvirus
- D. Laboratory confirmation is required for diagnosis (Correct Answer)
Explanation: ***Laboratory confirmation is required for diagnosis*** - The diagnosis of **molluscum contagiosum** is primarily **clinical**, based on the characteristic appearance of the lesions (small, flesh-colored, dome-shaped papules with central umbilication). - While histology can confirm the diagnosis by revealing **molluscum bodies**, it is **not routinely required** for typical cases. *Lesions contain characteristic inclusion bodies* - This statement is **true**. Histological examination of molluscum contagiosum lesions reveals large, eosinophilic cytoplasmic inclusions, known as **molluscum bodies** or **Henderson-Paterson bodies**, within infected epidermal cells. - These inclusion bodies contain viral particles and are a **hallmark of the infection**. *Autoinoculation can spread the infection to new sites* - This statement is **true**. Molluscum contagiosum is highly contagious, and scratching or touching existing lesions can lead to the spread of the virus to previously unaffected skin areas on the same individual. - This process of **autoinoculation** explains why lesions often appear in clusters or linear arrays (Koebner phenomenon). *It is caused by a poxvirus* - This statement is **true**. Molluscum contagiosum is caused by the **molluscum contagiosum virus (MCV)**, which belongs to the **Poxviridae family**. - Poxviruses are known for their relatively large size and the ability to replicate entirely in the cytoplasm of host cells.
Question 8: A young man presented with painful vesicular lesions distributed along a dermatomal pattern on one side of his body. What is the likely diagnosis?
- A. Lymphangioma circumscriptum
- B. Molluscum contagiosum
- C. Herpes simplex
- D. Herpes Zoster (Correct Answer)
Explanation: ***Herpes Zoster*** - This condition is characterized by a **unilateral rash** that respects the **dermatomal distribution**, meaning it follows the path of a single nerve. - The lesions are typically **painful vesicles** and crusts, often associated with a burning sensation due to reactivation of the **varicella-zoster virus** (chickenpox virus). *Lymphangioma circumscriptum* - This is a rare **lymphatic malformation** presenting as clusters of **vesicles** or papules, often described as 'frog spawn' or 'tapioca pudding' in appearance. - While it can be painful, it usually does not follow a dermatomal pattern and is a congenital condition, not an acute viral eruption. *Molluscum contagiosum* - This is a viral skin infection producing small, firm, **umbilicated papules** that are typically flesh-colored or pearly. - While contagious, these lesions are generally **asymptomatic** and do not present with the acute pain, blistering, or dermatomal distribution characteristic of herpes zoster. *Herpes simplex* - This infection causes localized clusters of painful **vesicles** on an erythematous base, most commonly around the mouth (cold sores) or genitals. - Unlike herpes zoster, herpes simplex lesions typically recur in the same small area and do **not follow a dermatomal distribution**.
Question 9: Multinucleated giant cell on Tzanck smear is not seen in?
- A. Herpes simplex
- B. Molluscum contagiosum (Correct Answer)
- C. Varicella
- D. Herpes zoster
Explanation: **Molluscum contagiosum** - Tzanck smear typically reveals **Henderson-Paterson bodies**, which are large eosinophilic intracytoplasmic inclusions within epithelial cells. - **Multinucleated giant cells** are not characteristic findings in lesions caused by the molluscum contagiosum virus (a poxvirus). *Herpes simplex* - Tzanck smear often shows **multinucleated giant cells** and **acantholytic cells**, which are specific cytopathic effects of HSV. - The presence of these cells helps in the rapid diagnosis of **herpes simplex viral infections**. *Varicella* - Similar to herpes simplex, **varicella-zoster virus (VZV)** infection also produces **multinucleated giant cells** on Tzanck smear. - These cells are a hallmark of **herpesvirus infections**, indicating viral cytopathic effects in epithelial cells. *Herpes zoster* - Herpes zoster, caused by the **reactivation of VZV**, also presents with **multinucleated giant cells** on Tzanck smear. - This finding aids in confirming the diagnosis of **shingles**, distinguishing it from other vesicular rashes.
Question 10: Which of the following is not a poxvirus?
- A. Molluscum contagiosum
- B. Orf virus
- C. Vaccinia virus
- D. Coxsackie virus (Correct Answer)
Explanation: ***Coxsackie virus*** - The **Coxsackie virus** belongs to the family **Picornaviridae**, not Poxviridae. - It is known for causing diseases such as **hand, foot, and mouth disease**, herpangina, and myocarditis. *Vaccinia virus* - **Vaccinia virus** is a well-known member of the **Poxviridae** family, historically used in the smallpox vaccine. - It is a **large, complex DNA virus** that replicates in the cytoplasm of infected cells. *Molluscum contagiosum* - **Molluscum contagiosum virus (MCV)** is a **poxvirus** that causes a mild skin infection characterized by raised, pearly, umbilicated lesions. - It primarily infects **humans**, causing localized lesions that are spread through direct contact. *Orf virus* - **Orf virus**, also known as contagious pustular dermatitis virus, is a **poxvirus** that primarily affects sheep and goats. - It can be transmitted to humans, causing single papular or nodular lesions, usually on the fingers, hands, or forearms.
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