Viral Skin Infections Practice Questions

Q: Infection by which virus gives rise to the following skin lesions?

Varicella zoster virus. ***Varicella zoster virus*** - Produces the characteristic **polymorphous vesicular rash** described as "**dew drops on rose petals**" - vesicles of different stages on an erythematous base. - The lesions appear in **crops** with vesicles, pustules, and crusts present simultaneously, typically starting on the **trunk** and spreading centripetally. *Herpesvirus* - Causes **grouped vesicles** on an erythematous base, typically clustered in a small area rather than widespread. - Lesions are usually **recurrent** at the same anatomical site and are **monomorphic** (same stage of development). *Measles virus* - Produces a **maculopapular rash** that starts behind the ears and spreads cephalocaudally, not vesicular lesions. - Associated with **Koplik's spots** in the mouth and systemic symptoms like **cough**, **coryza**, and **conjunctivitis**. *Parvovirus* - Causes **erythema infectiosum** with a characteristic "**slapped cheek**" appearance followed by a **lacy reticular rash** on extremities. - The rash is **maculopapular** and **non-vesicular**, completely different from the vesicular pattern described.

Q: What is the treatment of choice for genital warts in pregnancy?

Cryotherapy. **Explanation:** The treatment of choice for genital warts (Condyloma acuminata) in pregnancy is **Cryotherapy** (using liquid nitrogen). During pregnancy, the goal of treatment is to remove symptomatic warts and reduce the viral load before delivery to minimize the risk of juvenile-onset recurrent respiratory papillomatosis (JORRP) in the neonate. Cryotherapy is preferred because it is a **physical modality** that is safe, non-teratogenic, and lacks systemic absorption. **Why the other options are incorrect:** * **Podophyllotoxin (Option C):** This is strictly **contraindicated** in pregnancy due to its potent antimitotic effects, which can lead to systemic toxicity and potential fetal death or congenital anomalies. * **Imiquimod (Option B):** While it is an immune response modifier used for warts in non-pregnant patients, it is generally avoided in pregnancy due to a lack of sufficient safety data (Category C). * **Salicylic acid (Option A):** It is generally avoided for genital mucosal surfaces due to its corrosive nature and potential for systemic absorption (salicylism), especially over large surface areas. **High-Yield Clinical Pearls for NEET-PG:** * **Safe alternatives in pregnancy:** Trichloroacetic acid (TCA) 80-90% and surgical excision/electrocautery are also considered safe. * **Causative agents:** HPV types 6 and 11 (Low risk). * **Delivery Method:** Genital warts are *not* an absolute indication for Cesarean section unless they physically obstruct the birth canal or are likely to cause massive hemorrhage during labor. * **Most common viral STI:** HPV is the most common viral sexually transmitted infection worldwide.

Q: A 23-year-old, sexually active man has been treated for Neisseria gonorrhoeae infection 6 times during the past 5 years. He now comes to the physician because of the increasing number and size of warty lesions slowly enlarging on his external genitalia during the past year. On physical examination, there are multiple 1- to 3-mm sessile, nonulcerated, papillary excrescences over the inner surface of the penile prepuce. These lesions are excised, but 2 years later, similar lesions appear. Which of the following conditions most likely predisposed him to the development of these recurrent lesions?

Human papillomavirus infection. ### Explanation **Correct Answer: C. Human papillomavirus (HPV) infection** The clinical presentation of multiple, sessile, nonulcerated, papillary excrescences on the genitalia is classic for **Condyloma acuminatum** (anogenital warts). These are caused by **Human Papillomavirus (HPV)**, most commonly types **6 and 11**. The patient’s history of recurrent STIs (gonorrhea) indicates high-risk sexual behavior, which is the primary risk factor for acquiring HPV. The recurrence of these lesions after excision is a hallmark of HPV, as the virus often remains latent in the basal layer of the surrounding skin or mucosa, leading to new lesions even after the physical removal of visible warts. **Analysis of Incorrect Options:** * **A. Candida albicans:** Typically presents as balanitis (inflammation of the glans) with erythema, itching, and a "cheesy" white discharge, not as organized papillary growths. * **B. Circumcision:** This is actually a **protective factor**. Circumcision reduces the risk of acquiring HPV and other STIs because the removal of the prepuce eliminates a warm, moist environment conducive to viral persistence. * **D. Neisseria gonorrhoeae:** While the patient has a history of gonorrhea, this bacterium causes urethritis (purulent discharge and dysuria), not verrucous skin lesions. It does not predispose to warts, though its presence indicates a high risk for co-infection with HPV. **NEET-PG High-Yield Pearls:** * **Etiology:** HPV 6 and 11 (Low risk - warts); HPV 16 and 18 (High risk - associated with squamous cell carcinoma of the cervix, anus, and penis). * **Histopathology:** Look for **Koilocytes** (squamous epithelial cells with perinuclear halos and wrinkled "raisinoid" nuclei). * **Treatment:** Podophyllin, Imiquimod (immunomodulator), cryotherapy, or surgical excision. * **Prevention:** The quadrivalent and nonavalent HPV vaccines are effective against types 6 and 11.

Q: Which of the following is NOT true about Molluscum contagiosum?

It is treated with metronidazole and doxycycline.. **Explanation:** **Molluscum Contagiosum** is a common viral skin infection caused by a **Poxvirus** (specifically a double-stranded DNA virus). In adults, it is often transmitted sexually and presents as small, firm, pearly, umbilicated papules on the lower abdomen, thighs, or genitalia. **Why Option D is the correct answer (False statement):** Molluscum contagiosum is a **viral infection**, not a bacterial or protozoal one. **Metronidazole** is used for anaerobic bacteria and protozoa (like *Trichomonas vaginalis*), while **Doxycycline** is used for Chlamydia, Syphilis, or PID. These antibiotics have no efficacy against the poxvirus. Treatment for Molluscum is typically destructive (cryotherapy, curettage) or expectant, as it is often self-limiting. **Analysis of other options:** * **Option A:** Correct. It is caused by the *Molluscipoxvirus*, a member of the Poxviridae family. * **Option B:** Correct. While common in children, extensive or giant lesions in adults are a hallmark of **immunocompromised states**, particularly **HIV/AIDS**. * **Option C:** Correct. Management includes physical destruction of the lesions via **cryotherapy** (liquid nitrogen), curettage, or topical agents like podophyllotoxin or potassium hydroxide. **High-Yield Clinical Pearls for NEET-PG:** * **Pathognomonic Feature:** Central umbilication (dimple) on a pearly papule. * **Histopathology:** Presence of **Henderson-Paterson bodies** (large, intracytoplasmic eosinophilic inclusion bodies) is a classic exam finding. * **Transmission:** Skin-to-skin contact or fomites. In children, it is non-sexual; in adults, it is considered an STI. * **HIV Correlation:** If a patient presents with extensive facial molluscum, always screen for HIV.

Q: Which of the following occupations is a risk factor for the presenting illness?

A lifeguard in a swimming pool. ***A lifeguard in a swimming pool*** - **Molluscum contagiosum** spreads through direct contact with infected individuals and contaminated surfaces like **pool decks, diving boards**, and shared equipment. - Swimming pool environments facilitate **fomite transmission** as the virus can survive on wet surfaces and be transmitted through shared towels and pool equipment. *A poultry worker* - Poultry workers are at risk for **avian influenza**, **Salmonella**, and **Campylobacter** infections, not **molluscum contagiosum**. - **Molluscum contagiosum** is a **human-specific poxvirus** that does not affect or transmit through poultry. *Farmer* - Farmers are typically exposed to **zoonotic infections** like **anthrax**, **brucellosis**, and **Q fever** from livestock contact. - **Molluscum contagiosum** transmission occurs through **human-to-human contact** and contaminated surfaces, not agricultural exposure. *A kennel worker* - Kennel workers face risks of **dog bites**, **cat scratch disease**, **ringworm**, and **toxoplasmosis** from animal contact. - **Molluscum contagiosum** does not transmit from animals to humans as it is a **human-specific viral infection**.

Q: A female presents with multiple small, pink, umbilicated papules on the face. What is the most likely diagnosis?

Molluscum contagiosum. ***Molluscum contagiosum*** - This condition, caused by a **poxvirus**, classically presents as multiple, discrete, small (2-5 mm), dome-shaped, pink or skin-colored papules with central **umbilication**. - It is a common, benign skin infection that spreads through direct contact or fomites and is frequently seen in children, sexually active adults, and immunocompromised individuals. *Herpes simplex* - Herpes simplex virus infection typically manifests as clusters of painful **vesicles** (small blisters) on an erythematous base, which later ulcerate and crust over. - The primary lesions are not solid papules and lack the characteristic central umbilication seen in molluscum. *HPV* - Human Papillomavirus (HPV) causes warts (verrucae), which are typically rough, hyperkeratotic papules (**verruca vulgaris**) or flat-topped papules (**verruca plana**). - Warts do not characteristically present with the smooth surface and central depression seen in molluscum contagiosum. *Acne vulgaris* - Acne is a disorder of the pilosebaceous unit, presenting with a variety of lesions including **comedones** (blackheads and whiteheads), inflammatory papules, and pustules. - Acne lesions are not umbilicated and are often associated with follicular inflammation and sebum production.

Q: A Tzanck smear prepared from a vesicle shows multinucleated giant cells. What is the diagnosis?

HSV. ***HSV*** - The Tzanck smear is a rapid cytological test used to detect the viral cytopathic effects seen in vesicles caused by the *Herpesviridae* family, including **Herpes Simplex Virus (HSV)** and **Varicella-Zoster Virus (VZV)**. - The finding of **multinucleated giant cells** (also called **Tzanck cells**) formed by the fusion of infected keratinocytes is highly characteristic of herpetic infections. - **Important note**: The Tzanck smear **cannot distinguish between HSV and VZV** as both produce identical cytopathic effects. However, among the given options, **only HSV** is from the Herpesviridae family that causes vesicular lesions with this classic finding. - Clinical context (location, distribution, patient age) and confirmatory tests like **PCR** or **viral culture** are needed to differentiate HSV from VZV definitively. *HIV* - **HIV** (Human Immunodeficiency Virus) is diagnosed through blood tests, such as fourth-generation antigen/antibody screens or **PCR** for viral load. - The Tzanck smear is a test for vesicular dermatoses and **does not** play a role in the diagnosis of HIV infection. - HIV does not cause vesicles with multinucleated giant cells. *HPV* - **HPV** (Human Papillomavirus) causes warts and condylomas, which are diagnosed histologically showing characteristic **koilocytes** (squamous cells with perinuclear halos). - HPV lesions are **papular or verrucous**, not vesicular, and therefore would not yield multinucleated giant cells on Tzanck smear. - HPV does not belong to the Herpesviridae family. *EBV* - **EBV** (Epstein-Barr Virus) primarily causes Infectious Mononucleosis and is diagnosed using serological tests, such as the **Monospot test** (detecting heterophile antibodies) or EBV-specific antibodies. - EBV is **not associated with vesicular eruptions** and does not produce Tzanck-positive lesions. - EBV belongs to the Herpesviridae family but manifests systemically rather than with characteristic skin vesicles.

Q: A female patient presents to the OPD with complaints of recurrent lesions on lips, which is associated with fever. Which of the following is the characteristic feature seen in Tzanck smear?

Multinucleated giant cells. ***Multinucleated giant cells*** - Tzanck smear is a rapid diagnostic test for vesiculobullous lesions - In **Herpes Simplex Virus (HSV)** infection, the characteristic finding is **multinucleated giant cells** with nuclear molding (ballooning degeneration) - The clinical presentation of recurrent lip lesions with fever is classic for HSV-1 (herpes labialis) - Tzanck smear shows acantholysis and multinucleated keratinocytes *Acantholytic cells* - These are seen in **pemphigus vulgaris** (autoimmune blistering disorder) - Not characteristic of viral infections like HSV *Henderson-Paterson bodies* - These are intracytoplasmic inclusion bodies seen in **molluscum contagiosum** - Appear as eosinophilic structures (molluscum bodies) - Not seen in HSV infection *Owl eye appearance* - This describes large intranuclear inclusions seen in **Cytomegalovirus (CMV)** infection - Not characteristic of HSV infection

Q: A patient presented with multiple painful blisters on an erythematous base along a dermatome on the trunk as shown in the image. What is the diagnosis?

Herpes zoster. ***Herpes zoster*** - This diagnosis is indicated by the classic presentation of a **painful, unilateral vesicular eruption** on an erythematous base, which is confined to a single **dermatome**. - It is caused by the **reactivation** of the latent **varicella-zoster virus (VZV)** from the dorsal root ganglia, which previously caused chickenpox. *Herpes simplex* - Herpes simplex virus (HSV) typically causes vesicular lesions grouped around the **orolabial** (HSV-1) or **genital** (HSV-2) regions, not in a dermatomal pattern on the trunk. - While it can cause a widespread eruption (eczema herpeticum), it does not characteristically follow a single nerve distribution like herpes zoster. *Molluscum contagiosum* - This condition presents as discrete, flesh-colored, **dome-shaped papules** with central **umbilication**, not as painful vesicles on an erythematous base. - It is caused by a **poxvirus**, and the lesions are typically scattered and not confined to a dermatome. *Chicken pox* - Chickenpox (primary VZV infection) presents as a **generalized, diffuse vesicular rash** that affects the entire body, rather than being limited to a single dermatome. - The rash appears in successive crops, resulting in lesions at **various stages of development** (papules, vesicles, and crusted lesions) simultaneously.

Question 1

Infection by which virus gives rise to the following skin lesions?

Accepted Answer

Varicella zoster virus

Answer

Herpesvirus

Answer

Measles virus

Answer

Parvovirus

Question 2

What is the treatment of choice for genital warts in pregnancy?

Accepted Answer

Cryotherapy

Answer

Salicylic acid with lactic acid solution

Answer

Imiquimod

Answer

Podophyllotoxin

Question 3

A 23-year-old, sexually active man has been treated for Neisseria gonorrhoeae infection 6 times during the past 5 years. He now comes to the physician because of the increasing number and size of warty lesions slowly enlarging on his external genitalia during the past year. On physical examination, there are multiple 1- to 3-mm sessile, nonulcerated, papillary excrescences over the inner surface of the penile prepuce. These lesions are excised, but 2 years later, similar lesions appear. Which of the following conditions most likely predisposed him to the development of these recurrent lesions?

Accepted Answer

Human papillomavirus infection

Answer

Candida albicans infection

Answer

Circumcision

Answer

Neisseria gonorrhoeae infection

Question 4

Which of the following is NOT true about Molluscum contagiosum?

Accepted Answer

It is treated with metronidazole and doxycycline.

Answer

It is caused by a poxvirus.

Answer

It is commonly seen in HIV-infected and immunocompromised individuals.

Answer

Treatment can include cryotherapy.

Question 5

Which of the following occupations is a risk factor for the presenting illness?

Accepted Answer

A lifeguard in a swimming pool

Answer

A poultry worker

Answer

Farmer

Answer

A kennel worker

Question 6

A 25-year-old presents with painful vesicular lesions on the lips. A Tzanck smear from the lesion base shows multinucleated giant cells. What is the most likely causative agent?

Accepted Answer

Herpes simplex virus

Answer

Coxsackievirus A16

Answer

Human papillomavirus

Answer

Varicella-zoster virus

Question 7

A female presents with multiple small, pink, umbilicated papules on the face. What is the most likely diagnosis?

Accepted Answer

Molluscum contagiosum

Answer

Acne vulgaris

Answer

HPV

Answer

Herpes simplex

Question 8

A Tzanck smear prepared from a vesicle shows multinucleated giant cells. What is the diagnosis?

Accepted Answer

HSV

Answer

EBV

Answer

HIV

Answer

HPV

Question 9

A female patient presents to the OPD with complaints of recurrent lesions on lips, which is associated with fever. Which of the following is the characteristic feature seen in Tzanck smear?

Accepted Answer

Multinucleated giant cells

Answer

Acantholytic cells

Answer

Henderson-Paterson bodies

Answer

Owl eye appearance

Question 10

A patient presented with multiple painful blisters on an erythematous base along a dermatome on the trunk as shown in the image. What is the diagnosis?

Accepted Answer

Herpes zoster

Answer

Herpes simplex

Answer

Molluscum contagiosum

Answer

Chicken pox

Viral Skin Infections — MCQs

Viral Skin Infections — MCQs

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