Viral Skin Infections Practice Questions

Q: A teenager presented with a skin lesion that appeared as a thin, oval plaque with a fine collarette of scale located inside the periphery of the plaque. Pityriasis rosea is diagnosed. All of the following are characteristic of pityriasis rosea, except:

Lower respiratory infection. ***Lower respiratory infection*** - **Pityriasis rosea** is a self-limiting inflammatory skin condition, and while patients may experience mild prodromal symptoms like fatigue and malaise, a **lower respiratory infection** is not a characteristic feature or complication. - The disease is primarily a mucocutaneous eruption with no typical association with pulmonary involvement. *Herald patch* - The **herald patch** is the initial, solitary, larger lesion that precedes the generalized rash in pityriasis rosea. - It often appears a few days to two weeks before the widespread eruption and is a key diagnostic feature. *Moderate itching* - **Pruritus**, or itching, is a common symptom associated with pityriasis rosea, ranging from mild to moderate. - While not universally present or severe, it is a characteristic complaint for many patients. *Low grade fever* - Many patients with pityriasis rosea experience mild, **flu-like prodromal symptoms**, including a **low-grade fever**, malaise, and headache. - These symptoms typically precede the skin eruption and resolve as the rash develops.

Q: A 35-year-old professional businesswoman notices the appearance of several hyperkeratotic, well-demarcated growths on the palmar surface of her index finger and on her toe. They do not change in size and cause her only minimal discomfort. A biopsy of one of the lesions, viewed at 40x magnification, is shown. Which of the following viruses is the most likely etiologic agent?

HPV. ***HPV*** - The clinical description of **hyperkeratotic**, **well-demarcated growths** on the palmar surface and toe is highly characteristic of **warts** (verrucae), which are caused by **Human Papillomavirus (HPV)**. - The biopsy likely shows **koilocytes** (HPV-infected keratinocytes with perinuclear vacuolization), which are pathognomonic for HPV infection in the skin. *Adenovirus* - Adenovirus typically causes **respiratory tract infections**, **conjunctivitis**, or **gastroenteritis**, and less commonly skin lesions. - Skin manifestations from adenovirus are usually non-specific rashes, not hyperkeratotic growths like those described. *Molluscum contagiosum virus* - **Molluscum contagiosum** is caused by the **Molluscum contagiosum virus (MCV)** and presents as **umbilicated papules**, differing morphologically from the described hyperkeratotic warts. - Histologically, molluscum contagiosum lesions are characterized by **Molluscum bodies** (large eosinophilic cytoplasmic inclusions), which are different from koilocytes. *Echovirus* - Echoviruses are enteroviruses primarily associated with a wide range of syndromes including **aseptic meningitis**, **exanthems (rashes)**, and **respiratory illnesses**. - They do not typically cause localized, hyperkeratotic skin growths like warts.

Q: Which of the following infections can cause genital ulcers?

Herpes simplex virus (HSV). ***Herpes simplex virus (HSV)*** - HSV causes **painful, vesicular lesions** on the genitals that can rupture to form **ulcers** [1], [2]. - These infections are known for their recurrent nature and are one of the most common causes of **genital ulcers** [1], [2]. *Human papillomavirus (HPV)* - HPV primarily causes **genital warts** (condylomata acuminata), which are **flesh-colored, cauliflower-like growths**, not ulcers. - While some high-risk HPV types can lead to cervical or other anogenital cancers, they do not directly present as ulcers. *Syphilis (Treponema pallidum)* - Syphilis causes a **painless chancre** in its primary stage, which is a type of ulcer [1]. - However, the question asks which of the given options *can* cause genital ulcers, and HSV is a direct and common cause with the classic presentation of multiple painful ulcers [1]. *Human immunodeficiency virus (HIV)* - HIV itself does not directly cause genital ulcers. - However, it can increase an individual's susceptibility to other infections that do cause ulcers, or worsen the presentation of existing ulcer-causing STIs.

Q: In a primary lesion of herpes, what is typically seen?

vesicle. ***Vesicle*** - A primary herpes lesion typically begins as a **macule**, progresses to a **papule**, and then forms a classic **vesicle** (small, fluid-filled blister) on an erythematous base. - These vesicles often cluster together (**herpetiform**) and are characteristic of both HSV-1 (oral herpes) and HSV-2 (genital herpes) infections. *Ulcer* - An **ulcer** forms when the vesicles rupture and erode, which is a secondary stage of the lesion, not the primary eruption. - While ulcers are common in herpes infections, they represent a progression from the initial vesicular stage. *Papule* - A **papule** is a solid, raised lesion less than 1 cm in diameter, which is an early stage of herpes before fluid accumulation. - While present early, the defining primary lesion with fluid content is the vesicle, distinguishing it from other papular rashes. *Bullae* - **Bullae** are large blisters, greater than 1 cm in diameter, which are generally not typical for uncomplicated herpes simplex infections. - While extensive or severe infections might present with larger blisters, the classic primary lesion is a smaller vesicle.

Q: In a Tzanck smear, which condition is characterized by the presence of multinucleated giant cells?

Varicella (Chickenpox). ***Varicella (Chickenpox)*** * A **Tzanck smear** showing **multinucleated giant cells** and **acantholytic cells** is highly characteristic of herpesvirus infections, including varicella-zoster virus (VZV) causing chickenpox. * These giant cells are formed by the fusion of infected cells, and their presence helps confirm a diagnosis of either **herpes simplex** or **varicella-zoster** infection. *Psoriasis vulgaris* * A Tzanck smear in psoriasis typically shows **neutrophils** and **parakeratosis** (retained nuclei in the stratum corneum), but not multinucleated giant cells. * The primary pathology in psoriasis involves **epidermal hyperplasia** and inflammation, distinct from viral cytopathic effects. *Molluscum contagiosum infection* * Tzanck smears from molluscum contagiosum lesions reveal characteristic **molluscum bodies** (large eosinophilic intracytoplasmic inclusion bodies) within epithelial cells. * These inclusion bodies are distinctive for the **poxvirus** infection and are not multinucleated giant cells. *Pemphigus vulgaris* * A Tzanck smear in pemphigus vulgaris demonstrates **acantholytic cells** (rounded-up epidermal cells that have lost their adhesion to one another) due to autoantibody-mediated breakdown of desmosomes. * While acantholysis is present, the key differentiating feature is the *absence* of multinucleated giant cells, as it is an autoimmune blistering disease, not a viral one.

Question 1

A teenager presented with a skin lesion that appeared as a thin, oval plaque with a fine collarette of scale located inside the periphery of the plaque. Pityriasis rosea is diagnosed. All of the following are characteristic of pityriasis rosea, except:

Accepted Answer

Lower respiratory infection

Answer

Moderate itching

Answer

Low grade fever

Answer

Herald patch

Question 2

A 35-year-old professional businesswoman notices the appearance of several hyperkeratotic, well-demarcated growths on the palmar surface of her index finger and on her toe. They do not change in size and cause her only minimal discomfort. A biopsy of one of the lesions, viewed at 40x magnification, is shown. Which of the following viruses is the most likely etiologic agent?

Accepted Answer

HPV

Answer

Adenovirus

Answer

Molluscum contagiosum virus

Answer

Echovirus

Question 3

Which of the following infections can cause genital ulcers?

Accepted Answer

Herpes simplex virus (HSV)

Answer

Syphilis (Treponema pallidum)

Answer

Human papillomavirus (HPV)

Answer

Human immunodeficiency virus (HIV)

Question 4

In a primary lesion of herpes, what is typically seen?

Accepted Answer

vesicle

Answer

ulcer

Answer

papule

Answer

bullae

Question 5

In a Tzanck smear, which condition is characterized by the presence of multinucleated giant cells?

Accepted Answer

Varicella (Chickenpox)

Answer

Psoriasis vulgaris

Answer

Molluscum contagiosum infection

Answer

Pemphigus vulgaris

Viral Skin Infections — MCQs

Viral Skin Infections — MCQs

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