19.3 Immunologic and Allergic Conditions, Reactive Lesions and Physical or Chemical Injuries
Key Takeaways
Behçet disease combines recurrent oral aphthous ulcers with genital ulcers, eye inflammation (uveitis) and skin lesions, and is relatively common in the Middle East along the historic Silk Road.
Erythema multiforme starts abruptly with hemorrhagic crusting of the lips, widespread oral erosions and target skin lesions, often after herpes simplex infection or a drug.
True allergy to amide local anesthetics is rare; most reactions are vasovagal, epinephrine effects or sensitivity to sulfite or other additives, and suspected cases are referred for allergy testing.
Hereditary angioedema is a C1 esterase inhibitor deficiency in which dental trauma can trigger airway swelling that does not respond to epinephrine or antihistamines, so C1 inhibitor prophylaxis is planned with the physician.
After a child bites an electrical cord, the commissure burn can bleed from the labial artery about 1-2 weeks later when the eschar separates, so parents must be warned to apply pressure and return.
Many mucosal lesions are reactions: to the immune system, to an allergen, or to physical and chemical injury. The exam usually tests recognition and the first management step.
Immunologic Conditions
| Condition | Key features | Management |
|---|---|---|
| Behçet disease | Recurrent oral aphthae (at least 3 episodes per year) plus genital ulcers, uveitis, skin lesions (erythema nodosum, pathergy); associated with HLA-B51; relatively common in the Middle East, Turkey and East Asia | Topical corticosteroids for ulcers; systemic therapy (colchicine, immunosuppressants) by a physician; urgent eye referral |
| Systemic lupus erythematosus | Malar rash, palatal ulcers or lichenoid plaques, photosensitivity, arthritis, renal disease; ANA and anti-dsDNA | Medical management; check blood counts and renal function before surgery |
| Erythema multiforme | Abrupt onset in young adults; hemorrhagic crusted lips, diffuse erosions, target (iris) skin lesions; triggered by HSV or drugs; recurrent forms linked to HSV | Supportive care, fluids, sometimes systemic steroids; antiviral prophylaxis for HSV-associated recurrences |
| Stevens-Johnson syndrome / toxic epidermal necrolysis | Severe drug reaction (sulfonamides, anticonvulsants such as carbamazepine, allopurinol); skin detachment under 10% (SJS) or over 30% (TEN) | Stop the drug; emergency hospital care |
| Lichenoid drug reaction | Lichen planus-like lesions from drugs (NSAIDs, antihypertensives, antimalarials); contact lichenoid reaction next to amalgam | Change the drug or replace the restoration |
| Orofacial granulomatosis | Persistent lip swelling, angular cheilitis, cobblestone mucosa; may be linked to Crohn disease or dietary cinnamon and benzoates | Exclude Crohn disease, sarcoidosis, TB; dietary elimination, intralesional steroids |
| Graft-versus-host disease | Lichenoid lesions, xerostomia and mucositis after stem-cell transplant | Topical steroids, oral cancer surveillance |
Organ transplant recipients take immunosuppressants: expect candidiasis and viral infections, cyclosporine gingival enlargement, and an increased risk of lip squamous cell carcinoma.
Allergies
| Reaction | Mechanism | Dental examples |
|---|---|---|
| Type I (immediate, IgE) | Minutes; urticaria, angioedema, bronchospasm, anaphylaxis | Latex proteins, penicillin, chlorhexidine |
| Type IV (delayed, T-cell) | 48-72 hours; contact dermatitis or stomatitis | Methacrylate monomer, nickel, latex accelerator chemicals, flavouring agents |
- Latex allergy: higher risk in healthcare workers and patients with spina bifida or multiple surgeries; use a latex-free room and supplies, book the patient first in the day, and keep emergency drugs ready.
- Local anesthetic "allergy": true IgE allergy to amides is rare; most reactions are syncope, anxiety, intravascular epinephrine or sensitivity to sodium metabisulfite (in epinephrine-containing cartridges). Ester anesthetics produce PABA, a more common allergen. Refer for allergy testing before assuming allergy.
- Angioedema: IgE-mediated angioedema with urticaria responds to epinephrine and antihistamines. ACE inhibitor angioedema and hereditary angioedema are bradykinin-mediated: they do not respond well to epinephrine or antihistamines. Hereditary angioedema needs C1 inhibitor concentrate prophylaxis before dental surgery, arranged with the physician.
- Anaphylaxis management (intramuscular epinephrine 1 mg/mL, oxygen, emergency services) is covered with medical emergencies.
Physical and Chemical Injuries
| Injury | Clinical picture | Key action |
|---|---|---|
| Traumatic ulcer | Ulcer with a clear cause (sharp cusp, denture flange, biting) | Remove the cause; review in about 2 weeks; biopsy if not healed |
| Traumatic ulcerative granuloma with stromal eosinophilia | Deep, slow-healing tongue ulcer | Biopsy; heals after |
| Chemical burn | White necrotic slough: aspirin held against the mucosa, hydrogen peroxide, phenol, silver nitrate, sodium hypochlorite extrusion | Stop the cause; supportive care |
| Thermal burn | "Pizza burn" of the palate | Heals in days |
| Electrical burn | Child chews a live cord; gray-white burn of the commissure | Watch for delayed labial artery bleeding at 1-2 weeks; commissure splint to limit scarring |
| Frictional keratosis / morsicatio | Rough white shredded mucosa from cheek biting; linea alba along the occlusal plane | Reassure, remove habit |
| Nicotine stomatitis | White palate with red dots (inflamed minor salivary gland ducts) in pipe smokers or hot-drink users | Reversible after stopping |
| Actinic cheilitis | Atrophic, blurred lower lip vermilion after chronic sun exposure | Potentially malignant: sun protection, biopsy suspicious areas |
| Radiation and chemotherapy mucositis | See oncology section |
Reactive Hyperplasias
| Lesion | Typical site and features |
|---|---|
| Irritation fibroma | Firm pink nodule on the buccal mucosa along the bite line |
| Epulis fissuratum | Folds of fibrous tissue around an ill-fitting denture flange |
| Inflammatory papillary hyperplasia | Pebbly palate under a denture worn continuously |
| Pyogenic granuloma | Red, bleeding, often ulcerated gingival mass; common in pregnancy |
| Peripheral giant cell granuloma | Purple gingival mass only on gingiva or alveolar ridge; may "cup" the underlying bone |
| Peripheral ossifying fibroma | Gingival (interdental papilla) mass in young females; calcifications; recurrence after excision is relatively common |
Treat by excision down to periosteum (or bone for the peripheral lesions) and removal of the irritant; send tissue for histology.
Pigmented Lesions
- Amalgam tattoo: the most common localized oral pigmentation; gray-blue macule near an amalgam restoration or apicoectomy site; a radiograph may show metal particles. No treatment if diagnosis is certain; biopsy if doubtful.
- Physiologic pigmentation (symmetrical, gingival), smoker's melanosis (anterior mandibular labial gingiva), drug pigmentation (minocycline, antimalarials, imatinib), heavy metals (lead or bismuth line), Addison disease and Peutz-Jeghers syndrome.
- Oral melanoma most often affects the palate and maxillary gingiva; an expanding, irregular or multicolored pigmentation needs prompt biopsy.
Exam Traps
- Do not label a patient "allergic to lidocaine" after a faint; take a careful history and refer for testing.
- A traumatic ulcer that persists after the cause is removed is biopsied.
- Peripheral giant cell granuloma occurs only on the gingiva or alveolar mucosa.
A 24-year-old has had recurrent painful oral ulcers several times a year, plus genital ulcers and an episode of red, painful eye with blurred vision. What is the most likely diagnosis?
Oral lichen planus with skin lesions
Recurrent herpes labialis of the lips
Primary herpetic gingivostomatitis
Behçet disease
A 3-year-old bit an electrical cord two days ago and has a gray, depressed burn at the left commissure. What advice is most important to give the parents?
Labial artery bleeding may start 1-2 weeks later as the eschar separates
Apply an aspirin tablet directly onto the burn to reduce the pain and the risk of infection
The burn will heal without scarring in three days, so no further follow-up is needed at all
Immediate excision and skin grafting are needed today, before any edema develops further
A patient reports that after a previous injection of lidocaine with epinephrine they became pale, sweaty and fainted, then recovered within a minute when laid flat. What is the most appropriate conclusion?
The patient must receive only ester local anesthetics in all future appointments
The episode suggests a vasovagal faint rather than a true allergy to amide anesthetics
Local anesthesia is contraindicated, so all future dental care requires general anesthesia
The patient has a confirmed IgE allergy to all amide local anesthetics for life
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