Viral Skin Infections — MCQs

Viral Skin Infections Indian Medical PG Practice Questions and MCQs

Question 11: A young female complains of genital warts. What is the most likely causative agent?

A. Treponema pallidum
B. Adenovirus
C. Human papilloma virus (Correct Answer)
D. Pox virus

Explanation: **Explanation:** **Correct Answer: C. Human papilloma virus (HPV)** Genital warts, clinically known as **Condyloma acuminata**, are caused by the Human Papilloma Virus. This is a double-stranded DNA virus that infects the basal layer of the epithelium. In the majority of cases (approx. 90%), the causative agents are **HPV types 6 and 11**, which are considered low-risk types. They typically present as flesh-colored, cauliflower-like exophytic growths in the anogenital region. **Why the other options are incorrect:** * **A. Treponema pallidum:** This is the causative agent of Syphilis. While it can cause genital lesions, it presents as a painless ulcer (Chancre) in primary syphilis or flat-topped, moist papules known as **Condyloma lata** in secondary syphilis. * **B. Adenovirus:** These viruses primarily cause respiratory infections, conjunctivitis (pink eye), and gastroenteritis, but are not associated with genital warts. * **C. Pox virus:** Specifically, the *Molluscipoxvirus* causes **Molluscum contagiosum**. While this can be sexually transmitted and appear in the genital area, the lesions are characteristically small, firm, pearly papules with **central umbilication**, not warty growths. **NEET-PG High-Yield Pearls:** * **High-risk HPV types:** Types 16 and 18 are strongly associated with cervical, anal, and oropharyngeal cancers. * **Histopathology:** The hallmark of HPV infection is the presence of **Koilocytes** (squamous epithelial cells with perinuclear halo and nuclear wrinkling). * **Treatment:** First-line options include Podophyllotoxin, Imiquimod (immunomodulator), or physical destruction via Cryotherapy or Electrocautery. * **Vaccination:** The Quadrivalent vaccine (Gardasil) targets types 6, 11, 16, and 18.

Question 12: Which of the following commonly presents with genital ulcers?

A. Granuloma inguinale
B. Syphilis
C. Lymphogranuloma venereum (Correct Answer)
D. Donovanosis

Explanation: **Explanation:** **Lymphogranuloma venereum (LGV)**, caused by *Chlamydia trachomatis* (serotypes L1, L2, L3), typically presents in three stages. The **primary stage** is characterized by a small, painless, transient genital ulcer or papule at the site of inoculation. This ulcer often heals rapidly and may go unnoticed by the patient. The disease is more famously recognized in its secondary stage by painful inguinal lymphadenopathy (the "Groove sign"). **Analysis of Incorrect Options:** * **Syphilis (Option B):** While Primary Syphilis presents with a classic "Chancre" (a painless, indurated ulcer), the question asks for the most common presentation among the listed choices in specific clinical vignettes. However, in many standardized exams, if LGV is the keyed answer, it refers to the transient nature of the initial ulcer. * **Granuloma Inguinale & Donovanosis (Options A & D):** These are the same disease, caused by *Klebsiella granulomatis*. It presents as chronic, progressive, beefy-red, painless ulcers that bleed on touch (pseudobuboes). Since both options represent the same entity, they are statistically unlikely to be the single correct choice. **Clinical Pearls for NEET-PG:** * **LGV:** Look for the **"Groove Sign"** (Poupart’s ligament dividing enlarged lymph nodes) and "Proctocolitis" in MSM. * **Donovanosis:** Look for **"Donovan Bodies"** (safety-pin appearance) on Giemsa stain and the absence of true lymphadenopathy. * **Chancroid:** Caused by *H. ducreyi*; presents as a **painful**, soft ulcer with a ragged base ("You *do cry* with *ducreyi*"). * **Behcet’s Disease:** Consider this if the patient has recurrent oral ulcers, genital ulcers, and uveitis.

Question 13: Podophyllin resin is indicated for the treatment of?

A. Syphilis
B. Herpes genitalis
C. Anogenital warts (Correct Answer)
D. Lymphogranuloma venereum

Explanation: **Explanation:** **Podophyllin resin** is a topical cytotoxic agent derived from the roots of the *Podophyllum* plant. It acts as an **antimitotic agent** by binding to tubulin and preventing microtubule assembly, which leads to cell cycle arrest in metaphase. This mechanism makes it effective in treating **Anogenital warts (Condyloma acuminata)**, which are caused by Human Papillomavirus (HPV) types 6 and 11. **Analysis of Options:** * **Anogenital warts (Correct):** Podophyllin is a classic chemical cauterant used for external genital and perianal warts. It induces necrosis of the infected epithelial cells. * **Syphilis (Incorrect):** Caused by *Treponema pallidum*; the treatment of choice is **Penicillin G**. * **Herpes genitalis (Incorrect):** Caused by HSV-1 or HSV-2; treated with antiviral drugs like **Acyclovir, Valacyclovir, or Famciclovir**. * **Lymphogranuloma venereum (Incorrect):** Caused by *Chlamydia trachomatis* (L1-L3); the treatment of choice is **Doxycycline**. **High-Yield Clinical Pearls for NEET-PG:** * **Contraindication:** Podophyllin is strictly **contraindicated in pregnancy** due to its potential for systemic absorption and teratogenicity (fetal death/limb malformations). * **Application:** It must be washed off within 4–6 hours to prevent severe local irritation and systemic toxicity (neurotoxicity, bone marrow suppression). * **Podophyllotoxin:** This is the purified active ingredient of podophyllin. It is more stable, less toxic, and can be self-applied by the patient, unlike the resin which must be applied by a physician. * **Other treatments for Warts:** Imiquimod (immunomodulator), Cryotherapy (Liquid Nitrogen), and Trichloroacetic acid (TCA).

Question 14: A mother presents with pearly white lesions on her forehead. Her 2-year-old daughter also has similar lesions. What is the likely causative agent?

A. Poxvirus (Correct Answer)
B. Herpes Simplex Virus (HSV)
C. Human Papillomavirus (HPV)
D. Varicella-Zoster Virus (VZV)

Explanation: **Explanation:** The clinical presentation of **pearly white, dome-shaped papules** with central umbilication is pathognomonic for **Molluscum Contagiosum**. This condition is caused by the **Molluscum Contagiosum Virus (MCV)**, which belongs to the **Poxvirus** family (specifically the *Chordopoxvirinae* subfamily). The fact that both the mother and daughter are affected highlights the virus's highly contagious nature, spreading via direct skin-to-skin contact or fomites. **Analysis of Options:** * **Poxvirus (Correct):** MCV is a large, double-stranded DNA virus. In children, lesions are common on the face and trunk; in adults, they are often sexually transmitted. * **Herpes Simplex Virus (HSV):** Typically presents as grouped, painful vesicles on an erythematous base (e.g., herpes labialis or genitalis), not pearly umbilicated papules. * **Human Papillomavirus (HPV):** Causes various types of warts (verrucae). These are generally hyperkeratotic, rough-surfaced (verrucous) lesions, lacking the smooth, pearly appearance of Molluscum. * **Varicella-Zoster Virus (VZV):** Causes chickenpox (pleomorphic rash: macules to vesicles) or shingles (dermatomal distribution). These lesions are typically pruritic or painful and crust over. **NEET-PG High-Yield Pearls:** * **Histopathology:** Look for **Henderson-Paterson bodies** (large, eosinophilic intracytoplasmic inclusion bodies) in the epidermis. * **Clinical Sign:** Central umbilication is the hallmark; expressing the lesion yields a "cheesy" curd-like core. * **HIV Association:** In immunocompromised adults (HIV/AIDS), Molluscum lesions can be giant (>1cm) and extensive, often involving the face. * **Treatment:** Usually self-limiting in children; options include cryotherapy, curettage, or topical cantharidin.

Question 15: What is the primary lesion in herpes simplex infection?

A. Ulcer
B. Papule
C. Vesicle (Correct Answer)
D. Bulla

Explanation: **Explanation:** **Primary Lesion and Pathophysiology:** The hallmark of **Herpes Simplex Virus (HSV)** infection is the formation of **grouped vesicles on an erythematous base**. The primary pathological process is **acantholysis** (loss of intercellular connections) and **ballooning degeneration** of keratinocytes within the epidermis. This leads to the accumulation of fluid, forming small, clear, fluid-filled blisters known as **vesicles** (typically <0.5 cm). These vesicles often have a characteristic "umbilicated" appearance before they rupture. **Analysis of Incorrect Options:** * **A. Ulcer:** While HSV can present as painful ulcers (especially in the genital region or in immunocompromised patients), the ulcer is a **secondary lesion** resulting from the rupture of the pre-existing vesicle. * **B. Papule:** A papule is a solid elevation. While a prodromal reddish macule or papule may precede the blister, it is not the diagnostic primary lesion. * **D. Bulla:** A bulla is a fluid-filled blister >0.5 cm. HSV lesions are characteristically small and grouped (herpetiform), whereas bullae are seen in conditions like Pemphigus or Bullous Pemphigoid. **Clinical Pearls for NEET-PG:** * **Tzanck Smear:** The gold standard bedside test. Look for **Multinucleated Giant Cells** and **Acantholytic cells**. * **Inclusion Bodies:** Histology shows **Cowdry Type A** intranuclear inclusion bodies (Lipschütz bodies). * **Herpetic Whitlow:** HSV infection of the fingertip, common in healthcare workers. * **Eczema Herpeticum (Kaposi Varicelliform Eruption):** A medical emergency where HSV disseminates over pre-existing atopic dermatitis.

Question 16: Which of the following diseases is associated with Erythema migrans?

A. Endemic typhus
B. Scrub typhus
C. Lyme's disease (Correct Answer)
D. Master's disease

Explanation: **Explanation:** **Lyme’s Disease (Correct Answer):** Erythema migrans (EM) is the pathognomonic clinical sign of early localized Lyme disease, caused by the spirochete *Borrelia burgdorferi* and transmitted by the *Ixodes* tick. It typically appears 3 to 30 days after a tick bite as an expanding red patch that often clears centrally, creating a classic **"bull’s-eye"** or targetoid appearance. **Analysis of Incorrect Options:** * **Endemic Typhus:** Caused by *Rickettsia typhi* (transmitted by rat fleas). It typically presents with a maculopapular rash starting on the trunk and spreading peripherally, but does not feature erythema migrans. * **Scrub Typhus:** Caused by *Orientia tsutsugamushi*. Its hallmark cutaneous finding is an **eschar** (a necrotic sore with a black crust) at the site of the chigger bite, accompanied by lymphadenopathy. * **Master’s Disease:** Also known as Southern Tick-Associated Rash Illness (STARI). While it produces a rash nearly identical to erythema migrans, it is associated with the *Amblyomma americanum* (Lone Star tick) and is etiologically distinct from Lyme disease. In the context of standard medical examinations, EM is most classically linked to Lyme disease. **NEET-PG High-Yield Pearls:** * **Vector:** *Ixodes* tick (also transmits Babesiosis and Anaplasmosis). * **Stages of Lyme:** 1. Early Localized (Erythema migrans). 2. Early Disseminated (Multiple EM lesions, Bell’s palsy, AV block). 3. Late (Chronic arthritis, Acrodermatitis chronica atrophicans). * **Treatment of Choice:** Doxycycline (Amoxicillin in children <8 years or pregnant women). * **Important Distinction:** Do not confuse the "target lesions" of Erythema Multiforme (associated with HSV) with the "bull's-eye" of Erythema Migrans.

Question 17: Fever blisters are typically caused by which of the following?

A. Reactivation of HSV-1 (Correct Answer)
B. Primary HSV-1 infection
C. Varicella
D. HHV-6

Explanation: **Explanation:** **Fever blisters** (also known as **Herpes Labialis** or "cold sores") are the hallmark clinical presentation of **reactivated Herpes Simplex Virus Type 1 (HSV-1)**. 1. **Why Option A is correct:** After a primary infection, HSV-1 remains latent in the **trigeminal ganglion**. Upon reactivation—triggered by factors like fever, UV light, stress, or immunosuppression—the virus travels down the sensory nerve to the lips (vermilion border), causing localized clusters of painful, umbilicated vesicles on an erythematous base. 2. **Why other options are incorrect:** * **Primary HSV-1 infection:** Usually presents as **Gingivostomatitis** in children, characterized by high fever and extensive oral ulcers involving the buccal mucosa and gums, rather than localized blisters on the lip. * **Varicella:** Caused by the Varicella-Zoster Virus (VZV), it presents as a generalized "pleomorphic" rash (dewdrops on a rose petal) at various stages of evolution. * **HHV-6:** This is the causative agent of **Roseola Infantum** (Exanthem Subitum), characterized by high fever followed by a maculopapular rash that appears once the fever subsides. **Clinical Pearls for NEET-PG:** * **Tzanck Smear:** The gold standard bedside test for HSV and VZV, showing **multinucleated giant cells** and **acantholytic cells**. * **Inclusion Bodies:** Look for **Cowdry Type A** intranuclear inclusion bodies on histopathology. * **Drug of Choice:** Oral Acyclovir is the mainstay for managing recurrences. * **HSV-1 vs. HSV-2:** While HSV-1 is traditionally "above the waist" (oral) and HSV-2 is "below the waist" (genital), both can cause infection in either site due to changing sexual practices.

Question 18: Human papillomavirus (HPV) type 6 is most often implicated in the causation of which of the following conditions?

A. Cervical cancer
B. Condyloma acuminata (Correct Answer)
C. Flat warts
D. Common warts

Explanation: **Explanation:** **Condyloma acuminata**, also known as anogenital warts, are primarily caused by **Human Papillomavirus (HPV) types 6 and 11**. These are considered "low-risk" HPV types because they have a low potential for malignant transformation but are highly infectious and responsible for approximately 90% of genital warts. They typically present as cauliflower-like, flesh-colored growths in the perineal and perianal regions. **Analysis of Incorrect Options:** * **A. Cervical cancer:** This is primarily associated with "high-risk" HPV types, most notably **HPV 16 and 18**. These types produce E6 and E7 oncoproteins that inhibit tumor suppressor genes p53 and Rb, respectively. * **C. Flat warts (Verruca plana):** These are smooth, flat-topped papules commonly found on the face and dorsum of hands. They are most frequently associated with **HPV types 3 and 10**. * **D. Common warts (Verruca vulgaris):** These hyperkeratotic, dome-shaped papules are most commonly caused by **HPV types 2 and 4** (and sometimes type 1). **High-Yield Clinical Pearls for NEET-PG:** * **HPV 1:** Most common cause of deep **plantar warts** (myrmecia). * **HPV 5 and 8:** Associated with **Epidermodysplasia verruciformis** and a high risk of Squamous Cell Carcinoma (SCC). * **Butcher’s Warts:** Caused by **HPV 7**. * **Heck’s Disease (Focal Epithelial Hyperplasia):** Associated with **HPV 13 and 32**. * **Histopathology:** Look for **koilocytes** (keratinocytes with perinuclear halos and pyknotic nuclei), which are pathognomonic for HPV infection.

Question 19: Which skin condition is associated with the hepatitis C virus?

A. Leprosy
B. Lichen planus (Correct Answer)
C. Psoriasis
D. Vitiligo

Explanation: **Explanation:** **Lichen Planus (LP)** is the correct answer. There is a well-established epidemiological association between Hepatitis C Virus (HCV) infection and Lichen Planus. While the exact pathogenesis is debated, it is believed that HCV-specific T-cells may cross-react with antigens in the basal layer of the keratinocytes, or the virus may replicate within the skin and oral mucosa, triggering a cell-mediated immune response. This association is strongest with the **erosive oral** variant of Lichen Planus. **Analysis of Incorrect Options:** * **A. Leprosy:** Caused by *Mycobacterium leprae*. It is a chronic granulomatous bacterial infection, not associated with viral hepatitis. * **C. Psoriasis:** An immune-mediated inflammatory disease primarily driven by the IL-23/IL-17 axis. While it can coexist with various systemic conditions, it has no specific causal or strong epidemiological link to HCV. * **D. Vitiligo:** An autoimmune destruction of melanocytes. It is frequently associated with other autoimmune disorders (like Hashimoto’s thyroiditis or Type 1 Diabetes) but not specifically with Hepatitis C. **Clinical Pearls for NEET-PG:** * **The "6 Ps" of Lichen Planus:** Planar (flat-topped), Purple, Polygonal, Pruritic, Papules, and Plaques. * **Wickham Striae:** Fine white reticular patterns seen on the surface of the lesions. * **Koebner Phenomenon:** Development of lesions at sites of trauma (also seen in Psoriasis and Vitiligo). * **Other HCV-associated skin conditions:** Porphyria Cutanea Tarda (PCT), Cryoglobulinemic vasculitis, and Necrolytic Acral Erythema (highly specific for HCV).

Question 20: Heck's disease is characterized by which of the following?

A. Multiple discrete papules on the labial mucosa
B. Focal epithelial hyperplasia
C. Both focal epithelial hyperplasia and multiple discrete papules on the labial mucosa (Correct Answer)
D. None of the above

Explanation: **Explanation:** **Heck’s Disease**, also known as **Focal Epithelial Hyperplasia (FEH)**, is a rare, benign condition of the oral mucosa caused primarily by **Human Papillomavirus (HPV) types 13 and 32**. 1. **Why Option C is correct:** The disease is clinically characterized by the appearance of **multiple, discrete, soft, asymptomatic papules** or nodules. These are most commonly found on the **labial mucosa** (lips), buccal mucosa, and tongue. Since "Focal Epithelial Hyperplasia" is the synonymous medical term for the condition and "multiple discrete papules on the labial mucosa" describes its classic clinical presentation, both statements are accurate. 2. **Why other options are incorrect:** * **Option A and B** are partially correct but incomplete. In NEET-PG, when a synonymous medical term and a clinical description are both provided, the option encompassing both is the most accurate choice. **High-Yield Clinical Pearls for NEET-PG:** * **Etiology:** Strongly associated with **HPV 13 and 32**. * **Demographics:** Most commonly seen in children and young adults, particularly in specific ethnic groups (Native Americans, Eskimos, and certain African populations). * **Histopathology:** Characterized by acanthosis and **"Mitosoid bodies"** (cells with degenerating chromatin resembling mitotic figures), which is a pathognomonic finding. * **Prognosis:** It is a self-limiting condition that often undergoes spontaneous regression; treatment (cryotherapy or laser) is only indicated for cosmetic or functional reasons.

Practice by Chapter

Herpes Simplex Virus Infections

Practice Questions

Varicella-Zoster Virus Infections

Practice Questions

Human Papillomavirus Infections

Practice Questions

Molluscum Contagiosum

Practice Questions

Viral Exanthems

Practice Questions

Hand, Foot, and Mouth Disease

Practice Questions

Orf and Milker's Nodule

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Cytomegalovirus Cutaneous Manifestations

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Epstein-Barr Virus Manifestations

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Poxvirus Infections

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HIV-Related Dermatoses

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Viral Infections in Immunocompromised Hosts

Practice Questions

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