Oral Viral Infections Pathology
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Direct answer
Ballooning degeneration of keratinocytes, multinucleated epithelial giant cells and eosinophilic intranuclear inclusions (Cowdry type A) are the shared histological signature of the herpesviruses attacking oral mucosa — HSV types 1 and 2 and varicella-zoster virus — while the clinical pictures separate them: primary herpetic gingivostomatitis (fever plus vesicles and ulcers of a child, self-limiting in 10-14 days), recurrent herpes labialis (the UV- and fever-triggered cold sore of the vermilion), and trigeminal zoster with dermatomal pain and vesicles. The picornaviruses arrive as Coxsackie syndromes — herpangina (posterior palatal vesicles in a summer-month child) and hand-foot-mouth disease (anterior lesions plus extremity rash); Epstein-Barr virus drives infectious mononucleosis and hairy leukoplakia; human papillomaviruses produce squamous papilloma, verruca vulgaris, condyloma and focal epithelial hyperplasia (Heck disease). Therapy is acyclovir-family antivirals early in HSV and VZV, supportive care for Coxsackie disease, and antiretroviral resolution for hairy leukoplakia.
What you must remember
- Primary herpetic gingivostomatitis: HSV-1 in children; fever, cervical lymphadenopathy, vesicles on gingiva, tongue and palate breaking to shallow ulcers, anterior gingiva prominently involved; self-limiting 10-14 days; hydration, analgesia, acyclovir if early or severe; highly contagious.
- Recurrent HSV: latency in the trigeminal ganglion; reactivation triggers — ultraviolet light, fever, menstruation, immunosuppression; tingling prodrome, then clustered vesicles at the vermilion border or intraoral fixed keratinised sites; acyclovir or valacyclovir within the prodrome.
- VZV: primary varicella with oral vesicles alongside the exanthem; reactivation as unilateral, dermatomal, painful trigeminal zoster; nasal-tip vesicles (Hutchinson sign) threaten the eye; Ramsay Hunt syndrome adds ear vesicles and facial palsy; treat early with high-dose valacyclovir.
- Histology (all herpesviruses): intraepithelial vesicle with acantholysis, balloon degeneration, multinucleated giant cells with moulded nuclei, and Cowdry type A intranuclear inclusions — a guaranteed identification question.
- Coxsackieviruses: herpangina (group A) — sudden fever with posterior vesicles on soft palate and tonsillar pillars, summer-autumn, pre-school children; hand-foot-mouth disease — anterior oral ulcers plus palmar and plantar vesicles; both self-limiting; Kerala epidemics documented.
- EBV: infectious mononucleosis (fever, lymphadenopathy, atypical lymphocytes, positive heterophile antibody, palatal petechiae); hairy leukoplakia — corrugated lateral-tongue plaque in immunosuppression, not premalignant, resolving with antiretrovirals; links with endemic Burkitt lymphoma and nasopharyngeal carcinoma.
- HPV-associated benign lesions: squamous papilloma (HPV 6/11), verruca vulgaris (HPV 2/4, skin-to-mouth), condyloma acuminatum (HPV 6/11), and focal epithelial hyperplasia or Heck disease (HPV 13 and 32); managed by excision or laser.
- Measles and mumps: Koplik spots (bluish-white-centred buccal macules of the measles prodrome) and mumps parotitis (paramyxovirus, bilateral painful parotid swelling).
A typical clinical sorting exercise
Three children arrive in one clinic week, and the examiner expects them sorted without laboratory help. A two-year-old with high fever, drooling and clustered ulcers on tongue, palate and crusted gingiva: primary herpetic gingivostomatitis — supportive care, hydration, acyclovir if within 72 hours. A six-year-old in June with abrupt fever, refusal to swallow and vesicles confined to the soft palate and tonsillar fossae: herpangina — posterior location plus season decides; no antiviral needed. A four-year-old with anterior oral ulcers plus palmar and plantar vesicles: hand-foot-mouth disease. Now a 60-year-old with diabetes on steroids develops unilateral vesicles and severe maxillary-division pain: zoster — urgent ophthalmology review if the nose tip is involved (Hutchinson sign), immediate high-dose antiviral. None of these needs biopsy — but the HIV-positive patient with a non-wipeable corrugated lateral-tongue plaque does: hairy leukoplakia, EBV-driven, a CD4 surrogate, resolved by antiretroviral therapy rather than excision.
Where students slip
The herpangina versus hand-foot-mouth confusion is the most reliable trap: herpangina is posterior (soft palate, pharynx) without skin lesions; hand-foot-mouth is anterior plus extremity rash — location is the entire question. Second, recurrent intraoral herpes recurs only on keratinised fixed mucosa (hard palate, attached gingiva), which separates it from aphthae in a single line. Third, Tzanck multinucleated cells are credited to pemphigus by the unwary; in the smear context they belong to HSV and VZV. Fourth, hairy leukoplakia is mislabelled premalignant and confused with candidiasis — it will not wipe off, is EBV-positive, and carries no malignant potential. Finally, Koplik spots are mixed up with Fordyce granules; the bluish-white dot on an erythematous base opposite the molars, in a febrile child with catarrhal symptoms, is the exam picture.
Frequently asked questions
Which histological features are shared by HSV and VZV lesions?
Intraepithelial vesicles with ballooning degeneration, acantholysis, multinucleated giant cells with moulded nuclei and eosinophilic Cowdry type A intranuclear inclusions.
How do herpangina and hand-foot-mouth disease differ?
Both are Coxsackievirus infections, but herpangina causes posterior oropharyngeal vesicles without skin involvement, while hand-foot-mouth disease causes anterior oral ulcers plus palmar and plantar vesicles.
What triggers recurrent herpes labialis?
Reactivation of latent HSV-1 in the trigeminal ganglion by ultraviolet light, fever, respiratory infection, menstruation, trauma or immunosuppression, typically preceded by a tingling prodrome.
What is oral hairy leukoplakia and what causes it?
An EBV-driven corrugated white plaque on the lateral tongue border in immunosuppressed (classically HIV-positive) patients — not premalignant, not removable, resolving with antiretroviral therapy.
Which HPV types cause focal epithelial hyperplasia?
HPV types 13 and 32, producing multiple flat papules (Heck disease), reported in Indian kindreds.