Updates made (summary)
- Removed: images, citations, publication/admin text, learning outcomes.
- Re-structured into: high-yield disease tables (presentation → diagnosis → treatment) + clinical pearls callouts.
- Kept only clinically relevant differentiators (esp. adult “primary HSV-like” = consider immunosuppression, shingles unilateral dermatomal, syphilis stages, TB oral ulcer mimics malignancy, candida forms + predisposition + key drug interactions).
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Viral, Bacterial, Fungal Infections of the Oral Cavity — High-yield Summary
Viral infections
Herpes simplex virus (HSV-1 / HSV-2)
| Condition | Typical clinical presentation (most relevant) | Diagnosis (practical) | Treatment / management |
|---|---|---|---|
| Primary HSV-1 (primary herpetic gingivostomatitis) | Children (≈6 months–5 years). 1–2 weeks after exposure. Fever/malaise + diffuse oral ulceration + swollen erythematous gingiva (can mimic ANUG). Cervical LAD. Risk: dehydration. | Usually clinical. If needed: PCR (HSV DNA), viral culture (vesicle fluid). Consider FBC in adults to assess immunosuppression. | Supportive: analgesia/antipyretic + topical benzydamine/topical local anaesthetic + hydration (key). Acyclovir early/severe/immunocompromised. |
| Primary HSV-2 (oral) | Similar to HSV-1; often hard/soft palate (orogenital contact). | As above (PCR/culture if unclear). | As above. |
| Secondary HSV-1 (herpes labialis) | Prodrome tingling → erythema → vesicle → crust/ulcer → heals in ~5–7 days. Often recurrent at same site. Triggers: illness, UV, menses, pregnancy, stress, immunosuppression. | Clinical. | Topical acyclovir 5% or penciclovir 1% at prodrome (little benefit once blistered). |
| HSV in immunocompromised | More severe/prolonged; severe pharyngitis, extensive ulceration/exudate; frequent recurrences; can progress deeper → necrosis. | Lower threshold for PCR/culture + assess underlying immunosuppression. | Early systemic antivirals + manage underlying cause; consider complications (keratitis/encephalitis). |
Clinical pearl
Adult who looks like “primary herpetic gingivostomatitis” → suspect immunosuppression and investigate appropriately.
Infection control
HSV lesions: avoid direct contact to reduce transmission.
Varicella zoster virus (VZV)
| Condition | Typical clinical presentation (most relevant) | Diagnosis | Treatment / management |
|---|---|---|---|
| Chickenpox (primary VZV) | Preschool children. Generalised vesicular rash (macules → vesicles → crusts) + fever/malaise. Oral vesicles/ulcers may precede rash. | Clinical. PCR/serology if unclear. | Symptomatic (usually self-limited). Antivirals not routinely indicated. |
| Shingles / herpes zoster (secondary VZV) | Older/immunocompromised. Unilateral dermatomal vesicles/ulcers; trigeminal distribution possible (often ophthalmic > maxillary > mandibular). Can mimic toothache. | Clinical ± PCR. | Acyclovir 800 mg PO 5×/day for 7 days (generally indicated). Urgent ophthalmology if ophthalmic division suspected. Isolation/avoid contact (esp. vulnerable household members). |
| Key complication | Hallmark | Notes |
|---|---|---|
| Post-herpetic neuralgia (PHN) | Pain persists >3 months after rash healed | Treat early; counsel re prolonged pain risk. |
| Ramsay Hunt syndrome | Otitis externa + LMN facial nerve palsy + ipsilateral oral ulcers (tongue/soft palate) | Check ear canals + intraoral when zoster suspected. |
Clinical pearl
Zoster is typically unilateral with minimal midline crossover; bilateral involvement is rare.
Hand, foot and mouth disease (HFMD)
| Typical clinical presentation | Diagnosis | Treatment |
|---|---|---|
| Children (≈3–10). Fever/sore throat/malaise. Day 1–2: oral vesicles/ulcers (buccal/labial mucosa, tongue). Then vesicles on palms/soles. Usually resolves ~1 week. | Clinical (labs rarely needed). | Supportive: hydration + analgesia/antipyretics. |
Bacterial infections
Syphilis (Treponema pallidum)
| Stage | Key oral/clinical presentation (high-yield) | Diagnosis | Treatment (core) |
|---|---|---|---|
| Primary | Chancre: painless ulcer with indurated margin at inoculation site; painless LAD common. Oral sites: tongue/gingiva/palate/lips. | Serology (need both test types). PCR if available. | Benzathine penicillin IM per stage (local guidelines). |
| Secondary | Systemic symptoms + rash (incl palms/soles). Oral mucous patches ± “snail-track” lesions; highly infectious. | Serology: nontreponemal (RPR/VDRL) + treponemal confirm. | Penicillin regimen per stage; follow titres. |
| Latent | No clinical signs; detected on serology. | Serology. | Penicillin regimen depends on early vs late latent. |
| Tertiary | Gumma, destructive lesions; neuro/cardiovascular disease; oral palate/tongue involvement may cause fistula/osteonecrosis. | Serology ± CSF if neuro features. | Penicillin regimen guided by CSF / neurosyphilis status. |
| Congenital | Dental anomalies (e.g., Hutchinson teeth), high-arched palate; systemic features in neonate possible. | Maternal/infant testing (serology). | Treat per congenital protocols. |
Must-know testing rule: Do not rely on only one serologic test type (screen + confirm required).
Clinical pearl
Syphilis = “great imitator” → keep broad differential for atypical oral ulcers/plaques.
Gonorrhoea (Neisseria gonorrhoeae)
| Clinical presentation (most relevant) | Diagnosis | Treatment / management |
|---|---|---|
| Oropharyngeal involvement often asymptomatic or non-specific: diffuse erythema, small pustules, tonsillitis, LAD; may ulcerate with pseudomembrane. Can mimic aphthae/OLP/primary HSV. | NAAT is commonly used clinically (site-dependent). Gram stain not reliable for pharyngeal specimens (variable sensitivity/specificity). | Treat per current STI guidelines; consider resistance. Contact tracing + test/treat co-infections. |
Tuberculosis (TB) (Mycobacterium tuberculosis)
| Clinical presentation (most relevant) | Diagnosis | Treatment / management |
|---|---|---|
| Pulmonary: cough, fever, weight loss, night sweats, haemoptysis. Oral TB uncommon but important: indurated ulcer with ill-defined margins and necrotic base/slough; can mimic oral malignancy. | Screening: IGRA (preferred >2y) / TST (BCG confounds). Active disease: CXR + 3 sputum samples (microscopy/culture/molecular). Biopsy if oral lesion. | Multi-drug regimen (e.g., initial 4-drug phase then continuation) guided by susceptibility; public health / notifiable disease protocols. |
Clinical pearl
Oral TB ulcer can resemble cancer → biopsy/work-up and infection control precautions.
Fungal infections (Oral candidosis, Candida albicans most common)
Predisposing factors (high-yield)
| Local | Systemic |
|---|---|
| Dentures/trauma/poor hygiene; xerostomia (Sjögren, radiotherapy, meds); steroid inhalers; broad-spectrum antibiotics; smoking; high-carb diet; altered oral flora | Extremes of age, pregnancy; diabetes; nutritional deficiency (iron/folate/B12); malignancy; immunodeficiency (HIV); corticosteroids/anticancer therapy |
Clinical types of oral candidosis
| Type | Key clinical presentation (most relevant) | Diagnosis | Treatment / management |
|---|---|---|---|
| Pseudomembranous (thrush) | Wipeable white plaques → erythematous/bleeding base. Often immunocompromised / steroid use. | Usually clinical ± smear/cytology (PAS). Culture if needed. Consider bloods for underlying cause if recurrent/persistent. | Topical antifungal first-line if mild + correct factors. Consider systemic therapy if severe/refractory/immunocompromised. |
| Erythematous candidosis | Painful red/atrophic areas (often dorsum tongue) ± “kissing” palate lesions; associated with antibiotics or steroid inhalers. | Clinical ± swab/culture. | Antifungal + address trigger (rinse after inhaler, review antibiotics). |
| Chronic hyperplastic candidosis | Non-wipeable white plaque ± erythema; commissures/buccal mucosa/palate/tongue. | Biopsy to exclude dysplasia. | Antifungal + risk-factor control; manage per biopsy results. |
| Angular cheilitis (Candida ± S. aureus) | Fissuring/erythema at mouth corners; often with intraoral candidosis; consider anemia/B12 etc. | Clinical ± swab if persistent. Consider hematinics work-up if recurrent. | Treat corners + treat intraoral candidosis + correct predisposing factors. |
| Denture-associated erythematous stomatitis | Chronic erythema of denture-bearing mucosa (often palate). | Clinical. | Denture hygiene + antifungal as needed; avoid overnight wear; disinfect dentures. |
| Median rhomboid glossitis | Midline tongue papillary atrophy (rhomboid/elliptical). | Clinical. | Antifungal + address risk factors. |
| Linear gingival erythema | 2–3 mm linear erythematous band; classically HIV-associated; does not resolve with plaque control alone. | Diagnosis of exclusion after adequate plaque control; consider HIV risk assessment if appropriate. | Manage candida/underlying immunosuppression + periodontal care. |
Antifungals (practical note)
Drug interaction pearl
Miconazole is contraindicated with warfarin and some statins → consider nystatin or amphotericin B instead.