Viral Skin Infections — MCQs

Viral Skin Infections Indian Medical PG Practice Questions and MCQs

Question 31: Which of the following is a cutaneous marker of HIV?

A. Seborrhoeic dermatitis (Correct Answer)
B. Vesicular rash
C. Oral candidiasis
D. Photosensitivity

Explanation: **Explanation:** **Seborrhoeic Dermatitis (SD)** is considered one of the most common and earliest cutaneous markers of HIV infection. While it occurs in the general population, its presentation in HIV patients is typically **more severe, extensive, and recalcitrant** to standard treatment. It often involves atypical sites (trunk and extremities) beyond the classic "seborrhoeic areas" (scalp and face). The pathogenesis is linked to an abnormal immune response to *Malassezia* furfur amidst declining CD4 counts. **Analysis of Incorrect Options:** * **Vesicular rash:** This is a morphological description rather than a specific marker. While HIV patients can develop vesicular rashes (e.g., Herpes Simplex or Zoster), the term itself is too non-specific. * **Oral candidiasis:** This is a **mucosal** marker, not a cutaneous (skin) marker. While it is a classic sign of HIV progression (Oropharyngeal Candidiasis), the question specifically asks for a cutaneous marker. * **Photosensitivity:** While HIV patients can develop photosensitivity (e.g., Chronic Actinic Dermatitis), it is less common and less characteristic than Seborrhoeic Dermatitis. **High-Yield Clinical Pearls for NEET-PG:** * **Severity Correlation:** The severity of Seborrhoeic Dermatitis often correlates with a decline in **CD4+ T-cell counts** (usually <200-500 cells/mm³). * **Other Cutaneous Markers:** Kaposi Sarcoma (HHV-8), Eosinophilic Folliculitis, and Pruritic Papular Eruption (PPE) are other high-yield skin markers. * **Molluscum Contagiosum:** In HIV, look for giant lesions or involvement of the face/eyelids. * **Psoriasis:** HIV can trigger new-onset psoriasis or cause a sudden "explosive" flare of pre-existing disease.

Question 32: An eight-year-old boy presents with multiple umbilicated pearly white papules on the trunk and face following a viral infection. What is the diagnosis?

A. Molluscum Contagiosum (Correct Answer)
B. Chicken Pox
C. Herpes Zoster
D. Dermatophytosis

Explanation: **Explanation:** The clinical presentation of **multiple umbilicated pearly white papules** is the classic hallmark of **Molluscum Contagiosum**. This is a common viral skin infection caused by the **Molluscum Contagiosum Virus (MCV)**, a member of the **Poxvirus** family. The characteristic "umbilication" (a central depression) is due to the degeneration of keratinocytes, which forms a curd-like core containing viral particles known as **Henderson-Patterson bodies**. **Why other options are incorrect:** * **Chicken Pox (Varicella):** Presents with a pleomorphic rash (macules, papules, and vesicles in different stages) and is typically associated with fever and intense pruritus. The vesicles are often described as "dewdrops on a rose petal." * **Herpes Zoster:** Characterized by painful, grouped vesicles on an erythematous base, strictly following a **dermatomal distribution**. It is a reactivation of the latent Varicella-Zoster virus. * **Dermatophytosis:** This is a fungal infection (e.g., Ringworm) that typically presents as annular (ring-shaped) erythematous plaques with central clearing and peripheral scaling, not umbilicated papules. **High-Yield Clinical Pearls for NEET-PG:** * **Histopathology:** Look for **Henderson-Patterson bodies** (large, intracytoplasmic eosinophilic inclusion bodies). * **Transmission:** In children, it spreads via direct skin-to-skin contact or fomites (towels). In adults, if found in the anogenital region, it is considered a **Sexually Transmitted Infection (STI)**. * **HIV Association:** Extensive, giant, or recalcitrant lesions in an adult should prompt an investigation for underlying **HIV/immunosuppression**. * **Treatment:** Usually self-limiting; however, cryotherapy, curettage, or topical cantharidin are common interventions.

Question 33: Postherpetic neuralgia most commonly involves which division of the trigeminal nerve?

A. Maxillary division
B. Mandibular division
C. Ophthalmic division (Correct Answer)
D. None of the above

Explanation: **Explanation:** **Postherpetic Neuralgia (PHN)** is the most common chronic complication of Herpes Zoster (shingles), characterized by persistent neuropathic pain lasting more than 90 days after the onset of the rash. **Why the Ophthalmic Division is Correct:** Herpes Zoster occurs due to the reactivation of the Varicella-Zoster Virus (VZV) latent in the sensory ganglia. While the thoracic dermatomes are the most frequently involved site overall, the **Trigeminal nerve (Cranial Nerve V)** is the most common cranial nerve affected. Within the trigeminal nerve, the **Ophthalmic division (V1)** is involved significantly more often than the other branches. This clinical presentation is known as *Herpes Zoster Ophthalmicus (HZO)*. The high density of sensory fibers and the specific neurotropism of the virus for the ophthalmic branch make it the primary site for both acute infection and subsequent PHN in the head and neck region. **Why Other Options are Incorrect:** * **Maxillary (V2) and Mandibular (V3) divisions:** While these branches can be involved, they are statistically much less common than V1. V2 involvement typically presents with lesions on the upper lip or cheek, and V3 involves the lower jaw or tongue, but neither carries the same high risk of PHN as the ophthalmic branch. **High-Yield Clinical Pearls for NEET-PG:** * **Hutchinson’s Sign:** Vesicles on the side or tip of the nose indicate involvement of the nasociliary branch of V1, predicting a high risk of ocular complications (e.g., keratitis). * **Risk Factors for PHN:** Advanced age (>60 years), severe prodromal pain, and greater rash severity. * **Treatment:** First-line agents for PHN include Gabapentin, Pregabalin, and Tricyclic Antidepressants (Amitriptyline). * **Prevention:** The recombinant Zoster vaccine (Shingrix) is highly effective in preventing both HZ and PHN.

Question 34: Condyloma acuminatum is most commonly caused by which types of human papilloma virus (HPV)?

A. 18, 31
B. 17, 12
C. 6, 11 (Correct Answer)
D. 16, 18

Explanation: **Explanation:** **Condyloma acuminatum**, also known as anogenital warts, is a common sexually transmitted infection caused by the **Human Papillomavirus (HPV)**. The correct answer is **Option C (6, 11)** because these are the "low-risk" genotypes responsible for approximately 90% of all clinical cases of genital warts. These types cause benign epithelial proliferation but have a very low potential for malignant transformation. **Analysis of Incorrect Options:** * **Option A (18, 31) & Option D (16, 18):** These are "high-risk" oncogenic HPV types. While they can be found in the genital tract, they are primarily associated with **squamous cell carcinoma** of the cervix, anus, and penis, as well as high-grade intraepithelial neoplasia (CIN/AIN). HPV 16 is the most common type found in cervical cancer. * **Option B (17, 12):** These types are not typically associated with condyloma acuminatum. HPV 5 and 8 (and occasionally 12, 17) are more famously associated with **Epidermodysplasia verruciformis**, a rare genetic condition predisposing patients to skin cancer. **High-Yield NEET-PG Pearls:** * **Histopathology:** Look for **Koilocytes** (squamous cells with perinuclear halos and wrinkled "raisinoid" nuclei) in the upper epidermis. * **Treatment:** First-line options include Podophyllotoxin, Imiquimod (immunomodulator), or destructive methods like Cryotherapy and Electrocautery. * **Vaccination:** The Quadrivalent (Gardasil) and Nonavalent vaccines cover types 6 and 11 to prevent genital warts. * **Giant Condyloma Acuminatum:** Also known as the **Buschke-Löwenstein tumor**, it is a locally aggressive, cauliflower-like mass usually associated with HPV 6 and 11.

Question 35: Molluscum contagiosum is caused by which of the following:

A. Polyomavirus
B. Reovirus
C. Flavivirus
D. Poxvirus (Correct Answer)

Explanation: **Explanation:** **Molluscum Contagiosum (MC)** is a common viral skin infection caused by the **Molluscum Contagiosum Virus (MCV)**, which belongs to the **Poxviridae** family (specifically the genus *Molluscipoxvirus*). 1. **Why Poxvirus is correct:** Poxviruses are the largest known DNA viruses. MCV is a double-stranded DNA virus that replicates exclusively in the cytoplasm of keratinocytes. It induces characteristic large intracytoplasmic inclusion bodies known as **Henderson-Patterson bodies**, which displace the host cell nucleus. 2. **Why other options are incorrect:** * **Polyomavirus:** These are small DNA viruses associated with conditions like Progressive Multifocal Leukoencephalopathy (JCV) or Merkel cell carcinoma. * **Reovirus:** These are RNA viruses (e.g., Rotavirus) primarily causing gastrointestinal or respiratory infections. * **Flavivirus:** These are enveloped RNA viruses transmitted by arthropods, causing diseases like Dengue, Zika, and Yellow Fever. **High-Yield Clinical Pearls for NEET-PG:** * **Morphology:** Presents as firm, pearly, **umbilicated papules** (central depression). * **Transmission:** Skin-to-skin contact, fomites, or sexual transmission (in adults). * **Histopathology:** Shows "cup-shaped" invagination of the epidermis with **Henderson-Patterson bodies** (eosinophilic in the lower stratum malpighii, becoming basophilic towards the surface). * **Association:** Extensive or giant lesions in adults should prompt an investigation for **HIV/Immunosuppression**. * **Treatment:** Usually self-limiting; however, cryotherapy, curettage, or topical cantharidin are common interventions.

Question 36: Hand, foot, and mouth disease is characterized by which of the following?

A. Causes mini-epidemics in schools (Correct Answer)
B. Incubation period - 3-10 Days
C. Transmitted by a virus
D. Clinical features are similar to those seen in cows

Explanation: **Explanation:** **Hand, Foot, and Mouth Disease (HFMD)** is a highly contagious viral infection primarily affecting children under the age of 10. 1. **Why Option A is Correct:** HFMD is known for its high secondary attack rate. It spreads rapidly through direct contact with nasopharyngeal secretions, saliva, vesicle fluid, or fœcal-oral routes. Because children in close proximity share toys and facilities, it frequently leads to **mini-epidemics in schools and childcare centers**, especially during summer and autumn months. 2. **Why Other Options are Incorrect:** * **Option B:** The incubation period is typically **3–6 days**, not 3–10 days. While 10 days is sometimes cited as the upper limit for viral shedding, the standard clinical incubation period is shorter. * **Option C:** While HFMD *is* caused by a virus (Coxsackievirus A16 and Enterovirus 71), in the context of this specific question format, Option A is the most definitive epidemiological characteristic tested. (Note: In some exams, this might be a multiple-correct-choice question, but Option A is the classic "textbook" description of its social behavior). * **Option D:** This is a common distractor. HFMD is a human-only disease and is **unrelated to Foot-and-Mouth Disease (FMD)** found in cattle/cows, which is caused by an entirely different genus of Aphthovirus. **High-Yield Clinical Pearls for NEET-PG:** * **Etiology:** Most common cause is **Coxsackievirus A16**; most severe outbreaks (associated with encephalitis) are caused by **Enterovirus 71**. * **Morphology:** Characterized by "football-shaped" or elliptical vesicles on an erythematous base. * **Distribution:** Palmar and plantar surfaces, sides of fingers/toes, and painful oral erosions (stomatitis). * **Complication:** Keep an eye out for **Onychomadesis** (painless shedding of nails) occurring weeks after recovery.

Question 37: Podophyllin is used in the treatment of which condition?

A. Plantar warts
B. Palmar warts
C. Condylomata acuminata (Correct Answer)
D. Condylomata lata

Explanation: **Explanation:** **Podophyllin** is a cytotoxic resin derived from the Mayapple plant. It acts as an antimitotic agent by binding to tubulin and arresting the cell cycle in metaphase, leading to tissue necrosis and the eventual sloughing of the lesion. **1. Why Condylomata Acuminata is correct:** Condylomata acuminata, or **anogenital warts**, are caused by Human Papillomavirus (HPV) types 6 and 11. Podophyllin (usually in a 10–25% concentration) is a classic provider-applied chemical treatment for these soft, mucosal, or semi-mucosal warts. It is highly effective on moist surfaces but must be washed off after 4–6 hours to prevent systemic toxicity and local ulceration. **2. Why the other options are incorrect:** * **Plantar and Palmar Warts (Options A & B):** These are caused by HPV 1, 2, and 4. They are characterized by thick, hyperkeratotic skin (stratum corneum). Podophyllin has poor penetration through this thick keratin layer, making it ineffective. Salicylic acid or cryotherapy are preferred treatments. * **Condylomata Lata (Option D):** These are flat, moist papules seen in **Secondary Syphilis** (caused by *Treponema pallidum*). They are highly infectious and treated with **Benzathine Penicillin G**, not cytotoxic resins. **High-Yield Clinical Pearls for NEET-PG:** * **Contraindication:** Podophyllin is strictly **contraindicated in pregnancy** due to its potential teratogenic effects and risk of fetal death. * **Podophyllotoxin:** A purified derivative of podophyllin that is more stable and can be self-applied by the patient. * **Systemic Toxicity:** Over-application or failure to wash it off can lead to "Podophyllin Toxicity," presenting with bone marrow suppression, peripheral neuropathy, and coma.

Question 38: Herpes zoster ophthalmicus is a predictor of which of the following conditions?

A. Leukemia
B. Lymphoma
C. HIV
D. All of the above (Correct Answer)

Explanation: **Explanation:** **1. Underlying Medical Concept:** Herpes Zoster (Shingles) results from the reactivation of the latent Varicella-Zoster Virus (VZV) in the sensory ganglia. In a healthy individual, cell-mediated immunity (CMI) keeps the virus in check. **Herpes Zoster Ophthalmicus (HZO)**, which involves the ophthalmic division of the Trigeminal nerve, is particularly significant. When it occurs in young or middle-aged adults, or presents with severe, multi-dermatomal, or disseminated features, it serves as a clinical marker for **underlying immunosuppression.** **2. Analysis of Options:** * **HIV (Option C):** This is the most common association. HZO can be the first clinical sign of HIV infection. In HIV-positive patients, the risk of developing Zoster is 15–25 times higher than in the general population. * **Leukemia and Lymphoma (Options A & B):** Hematological malignancies, particularly Hodgkin’s Lymphoma and Chronic Lymphocytic Leukemia (CLL), severely impair T-cell function. This loss of surveillance allows VZV to reactivate. Patients with these malignancies have a significantly higher incidence of Zoster and a higher risk of post-herpetic neuralgia. * **Conclusion:** Since all three conditions cause the immunosuppression required for VZV reactivation, **"All of the above"** is the correct choice. **3. High-Yield Clinical Pearls for NEET-PG:** * **Hutchinson’s Sign:** Vesicles on the tip, side, or root of the nose indicate involvement of the nasociliary nerve and are a strong predictor of ocular complications in HZO. * **Disseminated Zoster:** Defined as >20 vesicles outside the primary and adjacent dermatomes; it necessitates a workup for internal malignancy or HIV. * **Ramsay Hunt Syndrome:** Involvement of the geniculate ganglion (CN VII) leading to facial palsy and vesicles in the external auditory canal. * **Treatment:** Oral Acyclovir (800mg 5 times/day for 7 days) is the gold standard; Valacyclovir is preferred for better bioavailability.

Question 39: Multiple squamous papillomas are characteristic of which condition?

A. Condyloma acuminatum
B. Cowden syndrome (Correct Answer)
C. Heck disease
D. Fordyce granules

Explanation: **Explanation:** **Cowden Syndrome (Multiple Hamartoma Syndrome)** is an autosomal dominant disorder caused by a mutation in the **PTEN gene**. The hallmark of this condition is the development of multiple hamartomas across various organs. In the oral cavity, these manifest as **multiple squamous papillomas** (often giving a "cobblestone" appearance to the gingiva and tongue). Cutaneous markers are highly diagnostic and include trichilemmomas, acral keratoses, and palmoplantar keratoses. **Analysis of Incorrect Options:** * **Condyloma acuminatum:** Caused by HPV types 6 and 11, these are anogenital warts. While they are papillomatous, they typically present as "cauliflower-like" clusters in the genital region rather than generalized multiple squamous papillomas associated with systemic syndromes. * **Heck disease (Focal Epithelial Hyperplasia):** Caused by HPV types 13 and 32, it presents as multiple smooth, flat-topped papules on the oral mucosa, primarily in children. These are not classified as classic squamous papillomas. * **Fordyce granules:** These are ectopic sebaceous glands appearing as small, yellowish-white papules on the oral mucosa or vermilion border. They are a normal anatomical variant, not neoplastic or papillomatous. **High-Yield Clinical Pearls for NEET-PG:** * **PTEN Mutation:** Cowden syndrome is part of the PTEN Hamartoma Tumor Syndrome (PHTS) spectrum. * **Malignancy Risk:** Patients have a significantly increased risk of **Breast cancer** (most common), **Thyroid cancer** (follicular variant), and **Endometrial cancer**. * **Lhermitte-Duclos disease:** A rare cerebellar dysplastic gangliocytoma is a pathognomonic feature of Cowden syndrome. * **Trichilemmomas:** Small, flesh-colored papules on the face are the most characteristic cutaneous finding.

Question 40: Human Papillomavirus (HPV) initially infects which cells?

A. Superficial epidermal cells
B. Basal cells (Correct Answer)
C. Subcutaneous cells
D. Dermal cells

Explanation: **Explanation:** **1. Why Basal Cells are Correct:** Human Papillomavirus (HPV) is a double-stranded DNA virus that specifically targets the **basal layer of the stratified squamous epithelium**. The virus gains entry through micro-abrasions or trauma in the skin or mucosa. It must reach the basal cells because these are the **proliferating (mitotically active) cells** of the epidermis. HPV utilizes the host cell's replication machinery to maintain its genome; as these basal cells divide and differentiate into upper layers, the virus undergoes its full life cycle, eventually shedding from the surface. **2. Why Other Options are Incorrect:** * **Superficial epidermal cells (Stratum Corneum/Granulosum):** While viral replication and assembly occur in these upper layers (koilocytosis is seen here), the *initial* infection must occur at the basal layer to establish a persistent infection. * **Dermal and Subcutaneous cells:** HPV is strictly **epitheliotropic**. It does not infect the dermis or subcutaneous fat because it lacks the necessary receptors to enter these non-epithelial cells and cannot replicate within them. **3. High-Yield Clinical Pearls for NEET-PG:** * **Koilocytes:** The pathognomonic histological feature of HPV infection, characterized by perinuclear halo and pyknotic nuclei, found in the **stratum spinosum and granulosum**. * **HPV Proteins:** **E6** (inhibits p53) and **E7** (inhibits Retinoblastoma/Rb protein) are the primary oncogenic proteins in high-risk types (HPV 16, 18). * **Common Associations:** HPV 6, 11 (Anogenital warts/Condyloma acuminata); HPV 1, 2 (Common warts/Verruca vulgaris). * **Vaccine:** The Gardasil-9 vaccine targets the L1 capsid protein.

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

Practice Questions

Cytomegalovirus Cutaneous Manifestations

Practice Questions

Epstein-Barr Virus Manifestations

Practice Questions

Poxvirus Infections

Practice Questions

HIV-Related Dermatoses

Practice Questions

Viral Infections in Immunocompromised Hosts

Practice Questions

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