19.2 Microbiological Infections of the Oral Mucosa: Fungal, Viral and Bacterial
Key Takeaways
Pseudomembranous candidiasis wipes off to leave a red surface, whereas hyperplastic candidiasis cannot be wiped off; denture stomatitis is treated by removing the denture at night, disinfecting it and using topical antifungals.
Miconazole and fluconazole can markedly raise the INR in patients taking warfarin.
Primary herpetic gingivostomatitis usually affects children aged about 6 months to 5 years with fever, generalized painful gingivitis and vesicles on keratinized and non-keratinized mucosa, and aciclovir helps if started early.
Herpangina (coxsackie A) causes vesicles and ulcers on the posterior soft palate and tonsillar pillars, while hand-foot-and-mouth disease adds vesicles on the hands and feet.
Congenital syphilis produces notched, screwdriver-shaped Hutchinson incisors and mulberry molars, and cervicofacial actinomycosis forms indurated swellings with multiple draining sinuses containing sulfur granules.
Oral infections often appear as "white lesion that wipes off", "fever with mouth ulcers in a toddler" or "sinus discharging yellow granules" in SDLE vignettes. Learn the pattern, the cause and the first-line treatment.
Fungal Infections
Candidiasis
| Form | Clinical features |
|---|---|
| Pseudomembranous (thrush) | Creamy white plaques that wipe off, leaving a red surface |
| Erythematous (atrophic) | Red areas, often after antibiotics or with inhaled steroids; includes median rhomboid glossitis (central papillary atrophy of the dorsal tongue) |
| Denture stomatitis | Erythema under a denture, usually maxillary; associated with continuous wear and poor denture hygiene |
| Angular cheilitis | Fissures at the commissures, Candida with Staphylococcus aureus; reduced vertical dimension and nutritional deficiency contribute |
| Hyperplastic | White plaque that cannot be wiped off, often at the commissures; can show dysplasia and needs biopsy |
| Chronic mucocutaneous | Persistent infection with immune or endocrine defects |
Predisposing factors: dentures, xerostomia, broad-spectrum antibiotics, inhaled or systemic corticosteroids (advise rinsing after inhaler use), diabetes, HIV and other immunosuppression, extremes of age.
Diagnosis: clinical, supported by a smear (hyphae with KOH or PAS staining) or culture.
Treatment:
- Topical: nystatin suspension or pastilles, clotrimazole troches, miconazole oral gel (strong interaction with warfarin).
- Systemic: fluconazole for extensive or resistant infection (also interacts with warfarin and some statins).
- Dentures: remove at night, clean and soak (for example in chlorhexidine), correct the fit.
- Angular cheilitis: miconazole cream (sometimes with hydrocortisone), correct vertical dimension and nutritional deficiencies.
Deep Fungal Infections
Mucormycosis affects patients with diabetic ketoacidosis or severe immunosuppression: palatal or nasal necrosis with a black eschar, sinus involvement and rapid spread. It needs urgent surgical debridement and intravenous amphotericin B. Aspergillosis and histoplasmosis are rarer.
Viral Infections
| Infection | Cause | Key features | Management |
|---|---|---|---|
| Primary herpetic gingivostomatitis | HSV-1 | Children about 6 months-5 years; fever, malaise, lymphadenopathy, generalized painful gingivitis, vesicles rupturing into ulcers on keratinized and non-keratinized mucosa; heals in about 10-14 days | Fluids, analgesia, soft diet; aciclovir if started early (within about 72 hours) |
| Recurrent herpes labialis | HSV-1 reactivation | Prodromal tingling, vesicles on the vermilion border | Topical or oral antivirals at prodrome (for example a one-day course of valaciclovir) |
| Herpetic whitlow | HSV | Painful finger lesion in clinicians without gloves | Prevented by gloves |
| Herpes zoster | Varicella zoster virus | Unilateral vesicles along a trigeminal division stopping at the midline; prodromal pain may mimic toothache; post-herpetic neuralgia | Antivirals within about 72 hours (valaciclovir or aciclovir) |
| Herpangina | Coxsackie A | Fever, vesicles and ulcers on the posterior soft palate and tonsillar pillars | Supportive |
| Hand-foot-and-mouth disease | Coxsackie A16, enterovirus 71 | Oral ulcers with vesicles on hands and feet | Supportive |
| Infectious mononucleosis | Epstein-Barr virus | Sore throat, lymphadenopathy, palatal petechiae, fatigue; rash if given amoxicillin | Supportive |
| Oral hairy leukoplakia | Epstein-Barr virus | Corrugated white plaques on the lateral tongue that do not wipe off; immunosuppression, especially HIV | Treat underlying cause |
| Squamous papilloma | HPV 6 and 11 | Pedunculated cauliflower-like growth | Excision |
| Multifocal epithelial hyperplasia (Heck disease) | HPV 13 and 32 | Multiple soft papules in children | Often observed |
| Measles | Morbillivirus | Koplik spots on the buccal mucosa before the rash | Supportive; vaccination |
| Mumps | Paramyxovirus | Painful parotid swelling | Supportive |
Oral Manifestations of HIV Infection
Oral candidiasis, oral hairy leukoplakia, Kaposi sarcoma (HHV-8; purple macules or nodules, often on the palate), linear gingival erythema, necrotizing periodontal diseases, HPV lesions, major aphthous-like ulcers and salivary gland disease. These lesions become less common with effective antiretroviral therapy, and their appearance can signal disease progression or treatment failure.
Bacterial Infections
Syphilis (Treponema pallidum)
| Stage | Oral features |
|---|---|
| Primary | Painless indurated ulcer (chancre) on the lip or tongue with lymphadenopathy, highly infectious |
| Secondary | Mucous patches, "snail-track" ulcers, rash |
| Tertiary | Gumma (palatal perforation), atrophic glossitis with increased cancer risk |
| Congenital | Hutchinson incisors (notched, screwdriver-shaped), mulberry (Moon) molars, saddle nose; Hutchinson triad of incisors, interstitial keratitis and deafness |
Diagnosis is serological (non-treponemal and treponemal tests); treatment is penicillin.
Tuberculosis
A chronic, painful ulcer with undermined edges, often on the dorsum of the tongue, or cervical lymphadenitis (scrofula). Biopsy shows caseating granulomas; acid-fast stains and cultures confirm. Refer for multidrug therapy and use airborne precautions for active pulmonary disease.
Actinomycosis
Cervicofacial actinomycosis (Actinomyces israelii) follows extractions or jaw trauma: a slowly enlarging woody, indurated swelling with multiple draining sinuses discharging pus containing yellow sulfur granules. Treatment is surgical drainage and debridement with a prolonged course of penicillin.
Other Bacterial Infections
Impetigo (honey-colored perioral crusts), scarlet fever (strawberry tongue), gonococcal pharyngitis and noma (cancrum oris in malnourished children) are less common but recognizable patterns.
Exam Traps
- A white plaque that wipes off is pseudomembranous candidiasis; one that does not wipe off needs further investigation.
- Unilateral vesicles stopping at the midline with a recent "toothache" suggest herpes zoster, not pulpitis.
- Amoxicillin given for a sore throat that is actually infectious mononucleosis causes a rash.
A 72-year-old who wears a maxillary complete denture day and night has diffuse erythema limited to the denture-bearing palate and angular cheilitis. What is the most appropriate management?
Reline the denture with hard acrylic only, without addressing its hygiene
Prescribe systemic amoxicillin, because the erythema is a bacterial infection
Biopsy the palate immediately, because diffuse erythema is usually carcinoma
Leave the denture out at night, disinfect it, and use a topical antifungal
A 3-year-old has fever, cervical lymphadenopathy, fiery red swollen gingiva and multiple small ulcers on the tongue, palate and lips that began two days ago. What is the most likely diagnosis?
Primary herpetic gingivostomatitis
Herpangina limited to the soft palate and tonsillar pillars
Necrotizing gingivitis caused by fusiform bacteria and spirochetes
Recurrent minor aphthous ulceration of the labial mucosa
Six weeks after extraction of tooth 38, a patient develops a hard, painless swelling at the angle of the mandible with several skin sinuses discharging pus containing yellow granules. Which organism is most likely responsible?
Mycobacterium tuberculosis causing a tongue ulcer
Treponema pallidum causing a tertiary gumma
Actinomyces israelii
Candida albicans causing deep tissue candidiasis
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