Viral Skin Infections — MCQs

A 40-year-old man developed burning pain and paresthesias of his left scalp and forehead for 9 days. Three days later, he noted several papules on his scalp, followed the next day by more on his forehead over the left eyebrow and on his left upper eyelid. These evolved into small blisters on which crusts formed. As the older lesions became crusted, new papules appeared in the same general area. Examination revealed several erythematous papules, and groups of clear-fluid-filled vesicles with erythematous bases, and crusted papules in the left anterior scalp, forehead, and upper eyelid. The tip of the nose was spared. If this same condition affects a pregnant female in the 1st trimester, which of the following abnormalities can be seen in the newborn?

Q128Easy

Systemic acyclovir in herpes zoster is useful:

Q129Easy

Multinucleate giant cells are seen in Tzank smear in which of the following conditions?

Q130Easy

Ramsay Hunt syndrome is caused by infection of which virus?

Viral Skin Infections Indian Medical PG Practice Questions and MCQs

Question 121: What is the best treatment option for Molluscum contagiosum?

A. Phototherapy
B. Immunosuppressives
C. Antiviral drugs
D. Electrocautery (Correct Answer)

Explanation: **Explanation:** **Molluscum contagiosum** is a common viral skin infection caused by a **Poxvirus** (Molluscipoxvirus). It is characterized by small, firm, pearly, umbilicated papules. **Why Electrocautery is correct:** The primary management of Molluscum contagiosum involves **physical destruction** of the lesions. Since the virus resides within the epidermis (specifically in the "molluscum bodies" or Henderson-Paterson bodies), mechanical removal or localized destruction is highly effective. **Electrocautery**, along with curettage, cryotherapy (liquid nitrogen), and expression of the central cheesy core, are standard first-line procedural treatments. **Why other options are incorrect:** * **Phototherapy (A):** This is used for inflammatory conditions like psoriasis or vitiligo; it has no role in treating viral papules. * **Immunosuppressives (B):** These would worsen the condition. Molluscum is more severe and widespread in immunocompromised patients (e.g., HIV/AIDS); hence, boosting or modulating the immune system (e.g., Imiquimod) is preferred over suppressing it. * **Antiviral drugs (C):** Systemic antivirals (like Acyclovir) are ineffective against Poxviruses. While Cidofovir can be used in severe, recalcitrant cases in HIV patients, it is not the standard "best" or first-line option for general cases. **High-Yield Clinical Pearls for NEET-PG:** * **Histopathology:** Look for **Henderson-Paterson bodies** (large, intracytoplasmic eosinophilic inclusion bodies). * **Transmission:** Skin-to-skin contact; in adults, it is often considered a **Sexually Transmitted Infection (STI)** if found in the anogenital region. * **Koebner Phenomenon:** It can show a positive pseudo-Koebner sign due to autoinoculation. * **Binkley’s Sign:** An inflammatory halo around the lesion, often signaling spontaneous resolution.

Question 122: Kaposi's varicelliform eruption is seen in which of the following conditions?

A. Darier disease (Correct Answer)
B. Varicella zoster
C. Pityriasis rosea
D. All of the above

Explanation: **Explanation:** **Kaposi’s Varicelliform Eruption (KVE)**, also known as **Eczema Herpeticum**, refers to a widespread cutaneous infection with the Herpes Simplex Virus (HSV-1 or HSV-2) occurring in patients with a pre-existing skin disease. **Why Darier Disease is Correct:** KVE typically occurs in patients with a compromised skin barrier. While **Atopic Dermatitis** is the most common underlying condition, **Darier disease** (a genetic disorder of keratinocyte adhesion) is a classic and high-yield association. The impaired integrity of the epidermis in Darier disease allows for the rapid, disseminated spread of the herpes virus, leading to characteristic monomorphic, "punched-out" erosions and vesicles. **Analysis of Incorrect Options:** * **Varicella Zoster:** While KVE is caused by a herpes virus, it is specifically a complication of HSV. Varicella-zoster virus (VZV) causes chickenpox or shingles, which are distinct clinical entities and do not represent the "eruption" on a pre-existing dermatosis defined by KVE. * **Pityriasis Rosea:** This is a self-limiting inflammatory condition (likely viral in origin, HHV-6/7). It does not typically involve the severe barrier dysfunction required to trigger a Kaposi’s varicelliform eruption. **High-Yield Clinical Pearls for NEET-PG:** * **Most Common Cause:** Atopic Dermatitis (Eczema Herpeticum). * **Other Associations:** Pemphigus foliaceus, Mycosis fungoides, and Ichthyosis. * **Clinical Feature:** Monomorphic vesicles, "punched-out" erosions, and systemic symptoms (fever, lymphadenopathy). * **Diagnosis:** Tzanck smear (shows multinucleated giant cells) or PCR. * **Treatment:** Systemic Acyclovir (Medical Emergency).

Question 123: Which of the following is NOT a stage of herpetic lesions?

A. Vesicle
B. Crusting
C. Chancre (Correct Answer)
D. Ulceration

Explanation: The correct answer is **C. Chancre**. ### **Explanation** Herpetic lesions, caused by the **Herpes Simplex Virus (HSV-1 or HSV-2)**, follow a classic evolutionary sequence of stages. A **Chancre**, however, is the hallmark of **Primary Syphilis** (caused by *Treponema pallidum*). It is characterized as a painless, indurated, clean-based ulcer, which is etiologically and clinically distinct from the painful, grouped vesicles of herpes. **Evolution of Herpetic Lesions:** 1. **Prodrome:** Tingling, itching, or burning sensation. 2. **Vesicle (Option A):** Small, "dew-drop on a rose petal" grouped vesicles on an erythematous base. 3. **Pustulation/Ulceration (Option D):** Vesicles rupture to form shallow, painful, punched-out erosions or ulcers. 4. **Crusting (Option B):** The lesions dry up, forming crusts (scabs) before healing without scarring (unless secondary infection occurs). ### **NEET-PG High-Yield Pearls** * **Tzanck Smear:** The gold standard bedside test for Herpes. Look for **Multinucleated Giant Cells** and **Acantholytic cells**. * **Inclusion Bodies:** HSV shows **Cowdry Type A** intranuclear inclusion bodies (Lipschütz bodies). * **Differentiating Genital Ulcers:** * **Herpes:** Painful, multiple, superficial vesicles/ulcers. * **Chancre (Syphilis):** Painless, single, indurated ulcer. * **Chancroid (*H. ducreyi*):** Painful, soft, "ragged" ulcer with inguinal lymphadenopathy (Bubo). * **Drug of Choice:** Oral Acyclovir (inhibits DNA polymerase).

Question 124: A lesion that is erythematous, recurrent, and distributed along a sensory nerve trunk is characteristic of which condition?

A. Herpes zoster (Correct Answer)
B. Erythema multiforme
C. Herpetic gingivostomatitis
D. Recurrent aphthous stomatitis

Explanation: **Explanation:** The clinical presentation described—lesions that are **erythematous**, **recurrent**, and follow a **sensory nerve trunk (dermatomal distribution)**—is the hallmark of **Herpes Zoster** (Shingles). **1. Why Herpes Zoster is correct:** Herpes Zoster is caused by the reactivation of the **Varicella-Zoster Virus (VZV)**, which remains latent in the sensory dorsal root ganglia after a primary chickenpox infection. Upon reactivation (often due to stress or immunosuppression), the virus travels down the sensory nerve to the skin, resulting in painful, erythematous vesicles strictly limited to the dermatome supplied by that nerve. While the primary infection is Varicella, the reactivation (Zoster) can be recurrent, especially in immunocompromised individuals. **2. Why other options are incorrect:** * **Erythema multiforme:** This is a hypersensitivity reaction characterized by "target" or "bull's eye" lesions. It is often triggered by HSV but is typically symmetrical and acral, not dermatomal. * **Herpetic gingivostomatitis:** This is the primary infection of HSV-1 involving the oral mucosa and gums. While it involves sensory nerves (Trigeminal), it presents as diffuse oral ulcerations rather than a linear trunk distribution. * **Recurrent aphthous stomatitis:** These are common "canker sores." They are painful mucosal ulcers but are not viral in origin and do not follow a nerve trunk. **Clinical Pearls for NEET-PG:** * **Tzanck Smear:** Shows **Multinucleated Giant Cells** (common to both HSV and VZV). * **Hutchinson’s Sign:** Vesicles on the tip of the nose indicating involvement of the nasociliary nerve (Ophthalmic division of Trigeminal nerve), signaling a high risk of ocular complications. * **Ramsay Hunt Syndrome:** Involvement of the geniculate ganglion leading to facial palsy and vesicles in the external auditory canal. * **Post-Herpetic Neuralgia (PHN):** The most common complication, defined as pain persisting >90 days after the rash heals.

Question 125: A middle-aged male presents with multiple painful blisters on an erythematous base along the T3 dermatome on the trunk. Which of the following etiological agents is most likely to be implicated?

A. Varicella zoster virus (Correct Answer)
B. Herpes simplex virus
C. Human papilloma virus
D. Pox virus

Explanation: ### Explanation **Correct Answer: A. Varicella zoster virus** The clinical presentation of **painful blisters on an erythematous base** distributed along a **single dermatome** (T3) is the classic hallmark of **Herpes Zoster** (Shingles). This condition is caused by the reactivation of the **Varicella Zoster Virus (VZV)**, which remains latent in the sensory dorsal root ganglia after a primary infection (Chickenpox). The virus travels down the sensory nerve to the skin, resulting in a unilateral, dermatomal eruption that does not cross the midline. **Analysis of Incorrect Options:** * **B. Herpes simplex virus (HSV):** While HSV causes grouped vesicles on an erythematous base, it typically presents as recurrent lesions on the lips (HSV-1) or genitalia (HSV-2). It is generally not dermatomal in distribution. * **C. Human papilloma virus (HPV):** HPV causes various types of warts (Verruca). These are characterized by hyperkeratotic, flesh-colored papules, not painful vesicles or blisters. * **D. Pox virus:** The most common dermatological manifestation is **Molluscum Contagiosum**, which presents as firm, pearly, umbilicated papules, typically painless and non-vesicular. **High-Yield Clinical Pearls for NEET-PG:** * **Tzanck Smear:** A rapid bedside test for VZV and HSV. Look for **Multinucleated Giant Cells** and **Acantholytic cells**. * **Hutchinson’s Sign:** Vesicles on the tip of the nose indicating involvement of the nasociliary branch of the ophthalmic nerve; it predicts ocular involvement in Zoster Ophthalmicus. * **Post-Herpetic Neuralgia (PHN):** The most common complication, defined as pain persisting >90 days after the rash heals. * **Ramsay Hunt Syndrome:** VZV reactivation in the geniculate ganglion involving CN VII and VIII (triad of facial palsy, ear pain, and vesicles in the external auditory canal).

Question 126: Which of the following conditions is a virus-induced epithelial hyperplasia?

A. Molluscum contagiosum
B. Focal epithelial hyperplasia
C. Squamous papilloma
D. All of the above (Correct Answer)

Explanation: **Explanation:** The correct answer is **D. All of the above**. The underlying medical concept is **Viral-induced Epithelial Hyperplasia**, which refers to the proliferation of keratinocytes or mucosal epithelial cells triggered by viral proteins (typically from DNA viruses). These viruses interfere with the host cell cycle (e.g., inhibiting p53 or pRb proteins), leading to benign localized growths. * **Molluscum contagiosum:** Caused by the **Poxvirus** (Molluscum contagiosum virus). It induces hyperplasia of the epidermis, characterized histologically by "Molluscum bodies" (Henderson-Paterson bodies) within the keratinocytes. * **Focal epithelial hyperplasia (Heck’s disease):** Caused by **HPV types 13 and 32**. It presents as multiple pink-to-white papules on the oral mucosa due to localized epithelial proliferation. * **Squamous papilloma:** Caused primarily by **HPV types 6 and 11**. It is a benign neoplastic proliferation of stratified squamous epithelium, resulting in a pedunculated or sessile finger-like growth. **NEET-PG High-Yield Pearls:** 1. **Molluscum Contagiosum:** Look for "umbilicated papules." In adults, if extensive or on the face, always screen for **HIV**. 2. **Verruca Vulgaris (Warts):** Also a form of viral epithelial hyperplasia caused by HPV (Types 1, 2, 4). 3. **Histology:** In HPV infections, look for **Koilocytes** (cells with perinuclear halos and wrinkled nuclei). 4. **Heck’s Disease:** Characteristically seen in children and specific ethnic groups (Native Americans/Eskimos), often regressing spontaneously.

Question 127: A 40-year-old man developed burning pain and paresthesias of his left scalp and forehead for 9 days. Three days later, he noted several papules on his scalp, followed the next day by more on his forehead over the left eyebrow and on his left upper eyelid. These evolved into small blisters on which crusts formed. As the older lesions became crusted, new papules appeared in the same general area. Examination revealed several erythematous papules, and groups of clear-fluid-filled vesicles with erythematous bases, and crusted papules in the left anterior scalp, forehead, and upper eyelid. The tip of the nose was spared. If this same condition affects a pregnant female in the 1st trimester, which of the following abnormalities can be seen in the newborn?

A. Cicatricial skin lesions (Correct Answer)
B. Sensorineural hearing loss
C. Macroopthalmia
D. Hyperpigmentation

Explanation: ### Explanation **Diagnosis:** The clinical presentation of unilateral, dermatomal burning pain followed by vesicular eruptions on the scalp, forehead, and eyelid (V1 distribution of the trigeminal nerve) is diagnostic of **Herpes Zoster (Shingles)**, caused by the reactivation of the Varicella-Zoster Virus (VZV). **1. Why Option A is Correct:** When a pregnant woman contracts a primary VZV infection (Chickenpox) or, rarely, a reactivation (Zoster) during the first 20 weeks of gestation (1st or early 2nd trimester), it can lead to **Congenital Varicella Syndrome**. The hallmark of this syndrome is **Cicatricial skin lesions** (zigzag scarring) in a dermatomal distribution. Other features include limb hypoplasia, microcephaly, and chorioretinitis. **2. Why the Other Options are Incorrect:** * **B. Sensorineural hearing loss:** This is a classic feature of the **Congenital Rubella Syndrome** (along with cataracts and PDA) or Congenital CMV, but not typically associated with VZV. * **C. Macroophthalmia:** VZV causes **Microphthalmia** (small eyes) and cataracts. Macroophthalmia is not a feature of congenital TORCH infections. * **D. Hyperpigmentation:** While post-inflammatory changes occur, the diagnostic feature for NEET-PG is specific **cicatricial (scarring) lesions**, not simple hyperpigmentation. **3. Clinical Pearls for NEET-PG:** * **Hutchinson’s Sign:** The question mentions the "tip of the nose was spared." If the tip of the nose is involved, it indicates involvement of the nasociliary nerve (V1 branch), predicting a high risk of ocular complications (Herpes Zoster Ophthalmicus). * **Tzanck Smear:** Shows **Multinucleated Giant Cells** with intranuclear inclusion bodies (Cowdry Type A). * **Treatment:** Oral Acyclovir (800 mg 5 times/day) is the drug of choice for Herpes Zoster. * **Neonatal Varicella:** If the mother develops chickenpox 5 days before to 2 days after delivery, the newborn is at risk of life-threatening disseminated disease due to lack of maternal antibodies.

Question 128: Systemic acyclovir in herpes zoster is useful:

A. When started immediately after the onset of rash (Correct Answer)
B. For post-herpetic neuralgia
C. For ocular lesions only
D. All of the above

Explanation: **Explanation:** The primary goal of systemic acyclovir in Herpes Zoster (Shingles) is to inhibit viral replication. The drug acts as a nucleoside analogue that inhibits viral DNA polymerase. **Why Option A is correct:** Acyclovir is most effective when initiated within the **"Golden Window" of 48 to 72 hours** after the onset of the rash. During this early phase, viral replication is at its peak. Early administration significantly reduces the duration of viral shedding, accelerates the healing of crusts, and limits the severity of acute pain. Once the lesions have crusted over, viral replication has largely ceased, rendering the antiviral therapy ineffective. **Why other options are incorrect:** * **Option B:** While early treatment of Zoster may slightly reduce the incidence of **Post-Herpetic Neuralgia (PHN)**, acyclovir is not a treatment for established PHN. PHN is a neuropathic pain condition managed with gabapentinoids (Pregabalin/Gabapentin) or tricyclic antidepressants (Amitriptyline). * **Option C:** Systemic therapy is indicated for ocular involvement (Herpes Zoster Ophthalmicus), but it is certainly not limited to it. It is also indicated for elderly patients (>50 years), immunocompromised individuals, and those with severe truncal or limb involvement. **High-Yield Clinical Pearls for NEET-PG:** * **Dosage:** The dose for Herpes Zoster is **800 mg five times a day for 7 days** (much higher than the 200 mg dose used for Herpes Simplex). * **Valacyclovir/Famciclovir:** These are now preferred over acyclovir due to better bioavailability and less frequent dosing (TID). * **Hutchinson’s Sign:** Vesicles on the tip of the nose indicate involvement of the nasociliary nerve, predicting a high risk of ocular complications. * **Tzanck Smear:** Shows **Multinucleated Giant Cells** (common to both HSV and VZV).

Question 129: Multinucleate giant cells are seen in Tzank smear in which of the following conditions?

A. Varicella-zoster virus (VZV) infection (Correct Answer)
B. Bullous pemphigoid
C. Toxic epidermal necrolysis
D. Pemphigus

Explanation: **Explanation:** The **Tzanck smear** is a rapid bedside diagnostic test used in dermatology to examine cells from the base of a vesicle. The presence of **multinucleate giant cells** (formed by the fusion of infected keratinocytes) is the hallmark cytological finding for infections caused by the **Herpesviridae** family. **1. Why Option A is Correct:** In **Varicella-zoster virus (VZV)** and **Herpes Simplex Virus (HSV)** infections, the virus causes characteristic cytopathic effects: acantholysis (loss of intercellular connections), ballooning degeneration, and the formation of multinucleated giant cells with "molding" of nuclei. **2. Why Other Options are Incorrect:** * **B. Bullous Pemphigoid:** A Tzanck smear typically shows numerous **eosinophils** and a lack of acantholytic cells, as the split is subepidermal. * **C. Toxic Epidermal Necrolysis (TEN):** The smear shows **necrotic keratinocytes** and inflammatory cells, but not multinucleate giant cells. * **D. Pemphigus:** While Tzanck smear is used here, it reveals **Acantholytic cells (Tzanck cells)**—which are rounded, large, intensely staining keratinocytes with a perinuclear halo—but these are typically **mononucleated**, not multinucleated. **Clinical Pearls for NEET-PG:** * **Mnemonic for Tzanck Smear:** "Tzanck Heavily" – **H**erpes simplex, **H**erpes zoster, **H**ailey-Hailey disease, and **P**emphigus vulgaris. * **Key Distinction:** Multinucleate giant cells = Viral (HSV/VZV); Mononucleate acantholytic cells = Pemphigus. * **Stains used:** Giemsa, Wright’s, or Leishman stain. * **Inclusion bodies:** Look for **Lipschütz bodies** (eosinophilic intranuclear inclusions) in HSV/VZV.

Question 130: Ramsay Hunt syndrome is caused by infection of which virus?

A. Herpes simplex virus
B. Varicella zoster virus (Correct Answer)
C. Adenovirus
D. Picornavirus

Explanation: **Explanation:** **Ramsay Hunt Syndrome (Herpes Zoster Oticus)** is caused by the reactivation of the **Varicella Zoster Virus (VZV)** within the **geniculate ganglion** of the facial nerve (CN VII). The classic clinical triad includes: 1. **Ipsilateral facial nerve palsy** (Lower Motor Neuron type). 2. **Otalgia** (Ear pain). 3. **Vesicular eruptions** on the external auditory canal, auricle, or oropharynx. Patients may also experience vestibulocochlear symptoms like vertigo or tinnitus due to the proximity of CN VIII. **Analysis of Incorrect Options:** * **A. Herpes Simplex Virus (HSV):** While HSV-1 is the most common cause of Bell’s palsy (idiopathic facial paralysis), it does not typically cause the painful vesicular rash characteristic of Ramsay Hunt Syndrome. * **C. Adenovirus:** Primarily associated with respiratory infections, conjunctivitis (epidemic keratoconjunctivitis), and gastroenteritis, not localized nerve ganglion reactivation. * **D. Picornavirus:** This family includes Poliovirus and Coxsackievirus (Hand-Foot-Mouth disease), which present with systemic or enteric symptoms rather than dermatomal zoster. **NEET-PG High-Yield Pearls:** * **Diagnosis:** Primarily clinical; Tzanck smear of vesicles shows **Multinucleated Giant Cells**. * **Treatment:** Combination of oral **Acyclovir/Valacyclovir** and **Corticosteroids** (to reduce nerve edema). * **Prognosis:** Ramsay Hunt has a poorer prognosis for full facial nerve recovery compared to Bell’s palsy. * **Hutchinson’s Sign:** Vesicles on the tip of the nose indicating VZV involvement of the nasociliary nerve (Ophthalmic division of CN V), signaling a high risk of ocular complications.

Practice by Chapter

Herpes Simplex Virus Infections

Practice Questions

Varicella-Zoster Virus Infections

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Human Papillomavirus Infections

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Molluscum Contagiosum

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Viral Exanthems

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Hand, Foot, and Mouth Disease

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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

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