Oral Lesion Description and Diagnostic Approach

Core Review

Primary Lesion Morphology

The NBDHE expects precise terminology. Every oral lesion can be classified by its primary morphology:

Macule: A flat, circumscribed area of color change. NOT elevated or depressed. Less than 1 cm in diameter.

• Examples: Oral melanotic macule, amalgam tattoo, petechiae
• Key point: Macules are NON-palpable — you can see them but cannot feel them

Patch: A macule larger than 1 cm in diameter. Flat, non-palpable area of color change.

• Examples: Erythroplakia (red patch), leukoplakia (white patch) — though leukoplakia often has a slightly roughened surface and may be considered a plaque

Papule: A solid, elevated lesion less than 1 cm in diameter. Palpable.

• Examples: Fibroma, early papilloma, Fordyce granules
• Key point: Papules are superficial — they involve the epithelium or superficial connective tissue

Nodule: A solid, elevated lesion greater than 1 cm in diameter, or a lesion extending deeper into the submucosa. Palpable, often firm.

• Examples: Pleomorphic adenoma, torus, fibroma (larger), neurofibroma
• Key point: Nodules extend deeper than papules — they are palpable as a distinct mass

Plaque: A flat-topped, slightly elevated lesion. Often has a rough, scaly, or fissured surface texture. Broader than it is tall.

• Examples: Leukoplakia, lichen planus (reticular/plaque forms), candidiasis (hyperplastic)
• Key point: Plaques are "plateau-like" — broader than tall

Vesicle: A fluid-filled blister less than 1 cm in diameter. The fluid may be clear (serous), bloody (hemorrhagic), or purulent. The roof is thin and easily ruptures in the oral cavity.

• Examples: Herpes simplex (initial lesions), herpes zoster, recurrent herpes labialis
• Key point: Oral vesicles are rarely seen intact — they quickly rupture to form erosions. If a patient presents with "multiple small ulcers," think ruptured vesicles.

Bulla: A fluid-filled blister greater than 1 cm in diameter. Larger and deeper than a vesicle.

• Examples: Pemphigus vulgaris, mucous membrane pemphigoid, bullous lichen planus, angina bullosa hemorrhagica
• Key point: Bullae in the oral cavity also rupture quickly, leaving large, irregular erosions. The distinction between vesicle and bulla is size (1 cm cut-off).

Pustule: A circumscribed collection of pus (neutrophils and debris) in the epithelium or subepithelium.

• Examples: Pustular psoriasis, acne vulgaris (skin), some candidiasis variants
• Key point: Pustules are uncommon in the oral cavity and are usually yellow-white

Erosion: A superficial loss of epithelium that does NOT extend through the full thickness of the epithelium. The basement membrane is intact. Heals without scarring.

• Examples: Ruptured vesicle/bulla, traumatic erosion (toothbrush abrasion), erosive lichen planus
• Key point: Appears red, moist, often painful. The key distinction from ulcer is depth — erosion = partial epithelial loss; ulcer = full-thickness epithelial loss.

Ulcer: A loss of the full thickness of the epithelium with exposure of the underlying connective tissue. The basement membrane is breached. May heal with scarring if deep enough.

• Examples: Aphthous ulcer, traumatic ulcer, squamous cell carcinoma (persistent, non-healing ulcer)
• Key point: Ulcers have a depressed center (yellowish fibrinopurulent membrane — the "diphtheritic membrane"), surrounded by a raised, erythematous border. The most important clinical rule: any non-healing ulcer present for >2 weeks should be biopsied to rule out malignancy.

Wheal (urticaria): A transient, edematous, irregularly shaped elevation caused by dermal edema. Itchy. Rare intraorally.

• Examples: Urticaria (hives), angioedema

Secondary Lesion Characteristics

Secondary features describe changes superimposed on primary lesions:

Scale: Accumulation of keratinized epithelial flakes. Common on skin (psoriasis); rare intraorally. Crust: Dried exudate (serum, blood, pus) on a skin surface. Not applicable intraorally (moist environment). Fissure: A linear crack or cleavage in the epithelium. May be painful.

• Examples: Fissured tongue, angular cheilitis Erosion and ulcer: As described above.

Systematic Lesion Description

The NBDHE expects you to approach any oral lesion with systematic descriptors:

1. Location: Where is it? Anatomical site (buccal mucosa, lateral tongue, hard palate, gingiva, etc.). Is it unilateral or bilateral? Solitary or multiple?
2. Size: Measure or estimate dimensions (mm or cm).
3. Color: Red (erythematous), white (keratotic/pseudomembranous), blue/purple (vascular, ecchymosis), brown/black (melanin, tattoo), yellow (pus, fat, Fordyce granules), mixed.
4. Shape/Outline: Round, oval, irregular, serpiginous (wave-like), linear.
5. Borders: Well-defined (circumscribed) vs. poorly defined (diffuse). Regular vs. irregular.
6. Surface: Smooth, rough, verrucous (warty), papillary, eroded, ulcerated, fissured.
7. Consistency (on palpation): Soft, firm, rubbery, hard (indurated), fluctuant (fluid-filled).
8. Fixation to underlying tissues: Mobile vs. fixed (suggests invasion).
9. Symptoms: Painful, tender, burning, pruritic (itchy), or asymptomatic.
10. Duration: How long has it been present? Acute (<2 weeks), subacute (2 weeks-3 months), chronic (>3 months).
11. Evolution: Has it changed in size, color, or symptoms? Is it getting better or worse?
12. Associated findings: Lymphadenopathy, fever, malaise, skin lesions, systemic symptoms.

Diagnostic Approach: The Lesion History

Use a systematic framework to gather the lesion history:

• Site — Where did it start? Has it spread?
• Onset — Sudden (hours/days = inflammatory, infectious, vascular) or gradual (weeks/months = neoplastic, autoimmune)?
• Character — Primary morphology and secondary features as above
• Relieving/Aggravating factors — What makes it better or worse?
• Timing — Constant or intermittent? Related to meals, stress, menstrual cycle?
• Exacerbating factors — Trauma, spicy/acidic foods, medications?
• Severity — Pain scale, impact on eating/speaking/swallowing
• Associated symptoms — Fever, rash, other lesions, systemic symptoms

The "Red Flags" — When to Refer/Biopsy

Certain clinical features raise concern for malignancy and warrant biopsy or prompt referral:

• Non-healing ulcer: Any ulcer persisting >2 weeks without an identifiable cause
• Erythroplakia: A red patch that cannot be characterized as any other specific disease. This is the oral lesion with the HIGHEST risk of dysplasia or carcinoma (~50-90% show dysplasia or carcinoma on biopsy)
• Non-homogeneous leukoplakia: Mixed red-and-white (erythroleukoplakia), verrucous, or nodular leukoplakia has higher malignant transformation risk than homogeneous leukoplakia
• Induration: Hardness on palpation suggests invasive growth and fibrosis
• Fixation to underlying tissues: Immobility suggests invasion beyond the mucosa
• Unexplained bleeding or paresthesia
• Rapid growth or change in a longstanding lesion
• Any pigmented lesion with ABCDE features (Asymmetry, irregular Borders, Color variation, Diameter >6mm, Evolution/change)

Differential Diagnosis by Lesion Type

White lesions (keratotic):

• Frictional (traumatic) keratosis — most common
• Leukoplakia (idiopathic — clinical term; defined as a white plaque that cannot be rubbed off and cannot be characterized as any other disease. Requires biopsy to determine histologic diagnosis.)
• Lichen planus (reticular — Wickham striae)
• Candidiasis (pseudomembranous — can be wiped off, leaving erythematous base)
• Hairy leukoplakia (corrugated white plaque on lateral tongue, HIV-associated — EBV)
• Smokeless tobacco keratosis

Red lesions (erythematous):

• Erythroplakia (HIGH risk — biopsy mandatory)
• Candidiasis (erythematous/atrophic form — "denture stomatitis")
• Vascular lesions (hemangioma, varix)
• Geographic tongue (erythema migrans — benign migratory glossitis)
• Telangiectasias (hereditary hemorrhagic telangiectasia — Osler-Weber-Rendu)

Vesiculobullous/ulcerative lesions:

• Aphthous ulcer (minor, major, herpetiform)
• Herpes simplex virus (HSV) — primary herpetic gingivostomatitis, recurrent herpes labialis, recurrent intraoral herpes
• Erythema multiforme (target lesions)
• Pemphigus vulgaris
• Mucous membrane pemphigoid
• Traumatic ulcer

Pigmented lesions:

• Oral melanotic macule (benign, most common oral pigmentation)
• Amalgam tattoo (most common exogenous pigmentation — gray/black, does NOT blanch)
• Melanoma (rare but deadly — any changing pigmented lesion)
• Racial pigmentation (physiologic melanosis)
• Peutz-Jeghers syndrome (perioral melanotic macules, associated with GI polyposis)

Clinical Application

The standard of care for any persistent oral lesion is documentation (photograph, measurement, description) and follow-up. The dental hygienist is often the first clinician to detect oral pathology during routine examination. The clinical approach is: (1) describe the lesion using precise terminology; (2) attempt to identify the lesion as a known benign condition (e.g., linea alba, Fordyce granules, geographic tongue); (3) if the lesion cannot be definitively identified as benign, or if red-flag features are present, refer for biopsy or specialty evaluation; (4) document all findings and recommendations.

Common Traps

• Confusing erosion with ulcer — erosion is shallow (basement membrane intact, no scarring); ulcer is deep (full-thickness, may scar)
• Thinking leukoplakia is a histologic diagnosis — it's a CLINICAL term (white plaque that cannot be scraped off and cannot be diagnosed as any other entity). The histologic diagnosis requires biopsy.
• Confusing pseudomembranous candidiasis (white, CAN be wiped off, leaves red base) with leukoplakia (white, CANNOT be wiped off)
• Thinking every white lesion is leukoplakia — most white lesions are frictional keratosis (identifiable cause), lichen planus, or candidiasis
• Forgetting that erythroplakia (red) has a higher malignant risk than leukoplakia (white)