Dermatology MCQ - Viral Infections - Primary Herpetic Gingivostomatitis

A 3-year-old child is brought to the clinic with a high fever, irritability, and refusal to drink. Physical examination reveals erythematous and edematous gingiva with multiple, small, painful ulcers on the tongue, buccal mucosa, and palate. The child is drooling excessively and has halitosis. There is no history of similar lesions. Which of the following is the most likely causative agent and its primary mode of transmission in this clinical scenario?

A) Varicella-zoster virus (VZV); respiratory droplets
B) Herpes simplex virus type 1 (HSV-1); direct contact with infected saliva
C) Coxsackievirus A16; fecal-oral route
D) Epstein-Barr virus (EBV); direct contact with infected saliva
E) Candida albicans; endogenous overgrowth

Correct Answer: B) Herpes simplex virus type 1 (HSV-1); direct contact with infected saliva

Explanation

This presentation is classic for primary herpetic gingivostomatitis, the most common symptomatic manifestation of primary HSV-1 infection in children.

Key Clinical Features:

• Acute Onset: High fever, malaise, irritability, and refusal to eat or drink due to pain.

• Oral Findings:

  • Gingivitis: Markedly erythematous, edematous, and friable gums that bleed easily.

  • Ulcers: Multiple, small (1-3 mm), painful, shallow ulcers with an erythematous halo on the tongue, buccal mucosa, palate, and gums.

  • Other Signs: Excessive drooling (due to pain on swallowing), halitosis (foul breath), and cervical lymphadenopathy.

• Course: Symptoms peak within 3-4 days and resolve spontaneously in 7-14 days.

Virologic Features:

• Causative Agent: >90% of cases are caused by herpes simplex virus type 1 (HSV-1).

• Transmission: Through direct contact with infected saliva (e.g., kissing, sharing utensils, or toys contaminated with saliva).

• Pathogenesis: After primary infection, HSV-1 establishes latency in the trigeminal ganglion and may reactivate later as herpes labialis (cold sores).

Why Not the Other Options?

• (A) Varicella-zoster virus (VZV): Causes chickenpox, which presents with a generalized vesicular rash (dew drops on a rose petal) and not localized painful gingivostomatitis.

• (C) Coxsackievirus A16: Causes hand, foot, and mouth disease, which presents with vesicles/ulcers on the oral mucosa BUT also on the palms and soles, and is associated with a milder prodrome without prominent gingivitis.

• (D) Epstein-Barr virus (EBV): Causes infectious mononucleosis, which may present with pharyngitis and tonsillar exudates, but not typically with gingival erythema and multiple small ulcers.

• (E) Candida albicans: Causes oral thrush, which presents with white, curd-like plaques that can be scraped off (leaving an erythematous base), not painful ulcers or gingivitis.

Management:

• Supportive Care: Hydration (oral or intravenous if necessary), analgesics (e.g., acetaminophen), and topical anesthetics (e.g., lidocaine mouth rinses).

• Antivirals: Oral acyclovir or valacyclovir may be used if started early (within 72 hours of onset) to reduce duration and severity.

• Nutrition: Soft, bland foods and cool liquids to avoid discomfort.

Complications:

• Dehydration is the most common complication.

• Autoinoculation may lead to herpetic whitlow or ocular involvement.

• Reactivation as herpes labialis (cold sores) may occur later in life.

Prognosis: Self-limiting in immunocompetent children, with full recovery within 2 weeks.