Oral Pathology: Infectious Mucosal Lesions

Overview of Infectious Mucosal Lesions¹

Infectious diseases of the oral mucosa can be categorized by their causative agents, primarily focusing on viral and bacterial pathogens. These lesions often present as vesicles, ulcers, or inflammatory changes within the oral cavity.

Viral infections often cause mucosal ulcerations or warty lesions.
Bacterial infections are generally uncommon in the oral mucosa due to the protective effects of saliva.
Fungal infections most commonly manifest as chronic ulcers or white/red lesions.

Viral Infections

Herpes Simplex Virus (HSV)
- Primary Herpetic Gingivostomatitis: Typically seen in children; characterized by widespread vesicles and ulcers, fever, and lymphadenopathy.
- Recurrent Herpes Simplex: Often occurs on the keratinized mucosa (lips, hard palate, gingiva) as “cold sores” or fever blisters.
Varicella-Zoster Virus (VZV)
- Chickenpox: Primary infection presenting with generalized skin rash and occasional oral vesicles.
- Herpes Zoster (Shingles): Recurrent infection following a dermatome; unilateral presentation of painful vesicles and ulcers.
Coxsackievirus
- Herpangina: Characterized by vesicles on the posterior soft palate and tonsillar pillars.
- Hand-Foot-and-Mouth Disease: Vesicles appearing on the oral mucosa, hands, and feet.

Bacterial Infections

Syphilis (Treponema pallidum)
- Primary: Chancre at the site of inoculation.
- Secondary: Mucous patches and maculopapular skin rash.
- Tertiary: Gumma formation (destructive granulomatous lesion).
Tuberculosis
- Chronic, non-healing oral ulcers, often secondary to pulmonary infection.
Actinomycosis
- Caused by Actinomyces israelii; characterized by “sulfur granules” in purulent discharge and firm swelling (lumpy jaw).

Viral Infections

Clinical Presentations³

Primary Infection
- Characteristics: Pan-oral, self-limiting, typically occurs in childhood.
- Treatment: Palliative care.
- Latency: Resides in the trigeminal ganglion.
Recurrent Infection
- Characteristics: Typically affects keratinized tissue.
- Herpes labialis (cold sore, fever blister): Occurs on the vermilion border.
- Recurrent intraoral herpes: Occurs on the attached gingiva and hard palate.
- Triggers: Reactivation is caused by stress, sunlight, or immunosuppression.

Herpes Simplex Virus

Specific Variants and Treatment

Herpetic whitlow: Infection of the finger; dental professionals should avoid patient contact until the lesion resolves.
Herpes gladiatorum: Infection of the head.
Treatment: Acyclovir administered during the prodromal period.

Varicella Zoster Virus

Clinical Stages⁴

Primary Infection: Varicella (chickenpox); self-limiting and typically occurs in childhood.
Latency: Resides in the trigeminal ganglion.
Recurrent Infection: Herpes zoster (shingles).

Associated Syndromes and Treatment

Ramsay Hunt Syndrome: Herpes zoster reactivation in the geniculate ganglion. It affects cranial nerves VII and VIII, resulting in facial paralysis, vertigo, and deafness.
Treatment: Acyclovir.

Coxsackie Virus

Clinical Manifestations⁵

Hand-foot-and-mouth disease
- Affects the hands, feet, and mouth.
Herpangina: Affects the posterior oral cavity, including the soft palate, throat, and tonsils.
- Specifically involves Waldeyer's ring.

Measles

Clinical Features⁶

Koplik’s spots: Ulcers on the buccal mucosa that precede the development of a skin rash.
Primary Infection: Self-limiting and typically occurs in childhood.

Cytology⁷

Variation in nuclear size and shape.
Hyperchromasia and nucleomegaly.

Morphologic Features

Papilloma

Papillary tumors characterized by fibrovascular cores.
Dysplastic epithelium exhibiting nuclear atypia.

Key Diagnostic Features

Papillary architecture.
Nuclear atypia.

Verruca Vulgaris

Characteristics

Caused by several strains of Human Papillomavirus (HPV).
Presents as a common skin wart.

Condyloma Acuminatum

Characteristics and Management

Etiology: Caused by HPV 6 and 11.
Transmission: Genital wart; may occur in the oral cavity via oral sex with an infected partner.
Treatment: Surgical excision; noted for a high rate of recurrence.

Focal Epithelial Hyperplasia

Characteristics and Management

Etiology: Caused by HPV 13 and 32.
Clinical Presentation: Multiple small, dome-shaped warts located on the oral mucosa.
Treatment: Surgical excision with an excellent prognosis.

Epstein-Barr Virus and Oral Hairy Leukoplakia

Clinical Features⁸

Etiology: Caused by Epstein-Barr Virus (EBV).
Presentation: White patch on the lateral tongue that does not wipe off.
Clinical Significance:
- Opportunistic infection strongly associated with HIV.
- Associated with Burkitt’s lymphoma.

Bacterial Infections

Epidemiology and Management⁹

Transmission: Caused by T. pallidum (spirochete) via sexual contact.
Screening: Not routinely screened for in pregnancy. Sexual partners must be notified and treated. Follow-up screening and treatment should occur at 3, 6, and 12 months post-treatment.
Treatment:
- Intensive parenteral penicillin G for standard cases.
- IM procaine penicillin G for pregnant women.

Syphilis

Clinical Stages

Primary: Characterized by a chancre (ulcer). Diagnosis may be delayed if untreated, as only larger lesions may be present.
Secondary: Characterized by condyloma lata, spirochetemia, skin rash, lymphadenopathy, fever, and headache. This stage is not considered infectious
- Oral mucous patch
- Maculopapular rash.
Tertiary: Characterized by endemic syphilis, gummas, and gummatous syphilis affecting the liver, CNS, heart, aorta, or eyes

Congenital Syphilis (Hutchinson’s Triad)

Teeth: Notched incisors and mulberry molars

Ears: Deafness

Eyes: Ocular keratitis .

Tuberculosis

Pathogenesis and Clinical Stages¹⁰

Etiology: Caused by the inhalation of Mycobacterium tuberculosis.
Oral Manifestations: Chronic, nonhealing oral ulcers following a lung infection.
Disease Progression:
- Primary: Ghon complex (inhaled bacteria in a granuloma with caseating necrosis plus an infected hilar lymph node draining the lesion). The hilum refers to the root of the lung.
- Secondary: Widespread lung infection with cavitation.
- Miliary: Systemic spread of the infection.

Risk Factors and Treatment

Risk: HIV patients are at high risk for progressive disease.
Treatment: Multidrug therapy including isoniazid, rifampin, and ethambutol.

Gonorrhea

Characteristics¹¹

Caused by Neisseria gonorrhoeae.
Oral pharyngitis is rarely observed.

Actinomycosis

Characteristics¹²

Etiology: Caused by Actinomyces israelii (a filamentous bacterium, not a fungus).
Nature: Chronic, granulomatous, opportunistic infection.

Clinical Presentations

Periapical: Infections involving the jaw.
Cervicofacial: Infections involving the head and neck.
Diagnostic Sign: Presence of “sulfur granules” in purulent exudate.

Treatment

Long-term, high-dose penicillin therapy.

Scarlet Fever

Pathogenesis and Clinical Features¹³

Etiology: Caused by Group A streptococcus (Streptococcus pyogenes).
Progression: Occurs when a streptococcal throat infection becomes systemic.
Oral Manifestation: Strawberry tongue (white-coated tongue with red, inflamed fungiform papillae).

Treatment

Penicillin.

These are usually involved with the inhalation of spores from the soil.

Fungal Infections

Clinical Variants¹⁴

Pseudomembranous: White plaques that can be rubbed off (thrush).
Atrophic: Red lesions.
Median rhomboid glossitis: Characterized by the loss of lingual papillae.
Angular cheilitis: Occurs at the corners of the mouth.

Candidiasis

Treatment

Antifungal medications (azoles or nystatin).

Deep Fungal Infections

Regional Variations and Etiology¹⁵

Blastomycosis: Found in the US Northeast; transmitted via spores.
Coccidioidomycosis: Found in the US Southwest; also known as valley fever.
Cryptococcosis: Found in the US West.
Histoplasmosis: Found in the US Midwest
- Histoplasmosis is specifically associated with the Ohio and Mississippi River valleys.

Audio Appendix

Additional Audio Content

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