Immunity, Oral Lesions, and Infectious Diseases in Dental Hygiene

Antigen

Any substance recognized by the immune system that triggers a response.

Antibody (Immunoglobulin)

Protein produced by plasma cells; binds to antigens.

B lymphocyte

Lymphocyte that differentiates into plasma cells (produce antibodies) or memory B cells.

T lymphocyte

Lymphocyte that matures in the thymus; helper, suppressor, cytotoxic, and memory functions.

Natural killer cell (NK)

Lymphocyte that destroys virus-infected and cancer cells.

Cytokine

Chemical messenger that regulates immune responses.

Macrophage

Large phagocyte; antigen presenter; no memory.

Dendritic cell

Antigen-presenting cell; connects innate and acquired immunity.

Immunity

Ability to resist infection; active or passive.

Hypersensitivity

Exaggerated immune response causing tissue destruction.

Autoimmunity

Immune system attacks self-antigens.

Immunodeficiency

Deficiency in immune response, congenital or acquired.

Inflammatory Response

A response characterized by immediate action and can cause tissue damage and systemic effects.

Immune Response

The body's defense mechanism against pathogens, which can be specific or nonspecific.

NK cell

Originates in bone marrow and functions to destroy virus-infected and tumor cells.

Passive - Natural Immunity

Acquired through maternal antibodies via the placenta; temporary.

Passive - Acquired Immunity

Acquired through injection of antibodies; temporary.

Active - Natural Immunity

Acquired through recovery from disease; long-term.

Active - Acquired Immunity

Acquired through vaccination; long-term.

Herd Immunity

Population-level protection that requires 70-90% coverage.

Hypersensitivity Reaction Type I

Immediate/Anaphylactic reaction involving IgE and histamine release; examples include anaphylaxis and asthma.

Hypersensitivity Reaction Type II

Cytotoxic reaction where IgG/IgM destroy target cells; examples include Rh incompatibility.

Hypersensitivity Reaction Type III

Immune complex reaction where antigen-antibody complexes deposit in tissue; examples include serum sickness.

Hypersensitivity Reaction Type IV

Cell-mediated reaction that is delayed; examples include TB and transplant rejection.

Aphthous Ulcers

Painful, recurrent oral lesions that can be minor, major, or herpetiform.

Urticaria

Type I hypersensitivity reaction characterized by itchy hives.

Angioedema

Type I hypersensitivity reaction resulting in diffuse swelling without itching.

Contact Mucositis/Dermatitis

Type IV hypersensitivity reaction causing red, swollen mucosa with burning sensation.

Erythema Multiforme

Acute, self-limiting condition characterized by target lesions and oral ulcers.

Sjögren Syndrome

Autoimmune disease characterized by dry eyes/mouth and parotid swelling.

Lupus (SLE)

Systemic autoimmune disease characterized by a butterfly rash and lichenoid oral lesions.

Pemphigus Vulgaris

Autoimmune condition with intraepithelial blisters and Nikolsky sign, leading to painful ulcers.

Xerostomia

Dry mouth associated with Sjögren Syndrome, ↑ caries risk, burning tongue, candidiasis

Systemic Lupus Erythematosus (SLE)

Multisystem autoimmune disease; butterfly rash; arthritis, nephritis, heart involvement

Oral lesions in SLE

Resemble lichen planus (lichenoid appearance, erythematous patches, white striae)

Oral findings in Pemphigus Vulgaris

Painful, nonhealing oral ulcers; intraepithelial blisters; positive Nikolsky sign (epithelium peels away)

Mucous Membrane Pemphigoid (Cicatricial pemphigoid)

Chronic, less severe than pemphigus; autoantibodies against basement membrane

Oral findings in Mucous Membrane Pemphigoid

Blisters → ulcers; gingival desquamation ("peeling gums"); scarring possible (esp. eyes)

Bullous Pemphigoid

Autoimmune blistering, older adults; also antibodies vs. basement membrane

Oral findings in Bullous Pemphigoid

Blisters & ulcers, less oral involvement than mucous membrane pemphigoid

Behçet Syndrome

Systemic vasculitis; recurrent episodes

Triad of Behçet Syndrome

Recurrent painful oral ulcers, genital ulcers, ocular inflammation

Oral ulcers in Behçet Syndrome

Resemble aphthous ulcers; Tx = immunosuppressants

Pemphigus

Intraepithelial, severe, Nikolsky +

Pemphigoid

Subepithelial, scarring (esp. eyes)

Sjögren

dry mouth + eyes

Lupus

butterfly rash + lichenoid lesions

Behçet

triad (oral + genital + eye lesions)

Humoral immunity

antibodies; defense against some microorganisms

Cell-mediated immunity

T cells; defense against intracellular pathogens (bacteria, viruses, fungi)

Opportunistic infection

disease from normally nonpathogenic organisms due to ↓saliva, antibiotics, immune suppression

Oral candidiasis

Opportunistic infection common in denture wearers, immunocompromised, xerostomia, diabetes, antibiotics, steroids

NUG

necrotizing ulcerative gingivitis

Impetigo

Causative Agent: Streptococcus pyogenes, Staphylococcus aureus; Requires nonintact skin, contagious; Oral Manifestations: Vesicles → amber crusts, perioral area; Diagnosis: Clinical; Treatment: Topical/systemic antibiotics

Tonsillitis/Pharyngitis

Causative Agent: Group A β-hemolytic strep; Transmission: Saliva, nasal/oral secretions; Oral Manifestations: Sore throat, fever, tonsillar hyperplasia, erythema; Diagnosis: Clinical; Treatment: Symptomatic

Scarlet Fever

Causative Agent: Group A strep toxin; Transmission: Post-pharyngitis; Oral Manifestations: Petechiae on soft palate, strawberry tongue; Diagnosis: Clinical; Treatment: Antibiotics

Rheumatic Fever

Causative Agent: Autoimmune reaction post-strep; Follows strep throat; Oral Manifestations: Carditis, arthritis, CNS involvement; may need premed for dental; Diagnosis: Clinical history; Treatment: Medical referral

Tuberculosis

Causative Agent: Mycobacterium tuberculosis; Transmission: Inhalation, aerosols; Oral Manifestations: Rare oral ulcers (painful, nonhealing), cough, fever, weight loss; Diagnosis: Biopsy, PPD skin test, chest X-ray; Treatment: Combo drugs (INH, rifampin, rifapentine); defer dental if active

Actinomycosis

Causative Agent: Actinomyces israelii; Transmission: Endogenous; Oral Manifestations: Draining abscesses with 'sulfur granules'; Diagnosis: Clinical, culture; Treatment: Long-term antibiotics

Syphilis

Causative Agent: Treponema pallidum; Transmission: Sexual, blood, transplacental; Oral Manifestations: 1° chancre; 2° mucous patches; 3° gumma (palatal perforation); Diagnosis: VDRL, FTA-ABS, dark-field microscopy; Treatment: Penicillin

Congenital Syphilis

Transmission: Transplacental; Oral Manifestations: Facial/dental anomalies; Diagnosis: Clinical, labs; Treatment: Medical

Pericoronitis

Causative Agent: Mixed flora; Transmission: Impacted 3rd molars; Oral Manifestations: Red, swollen operculum; Diagnosis: Clinical; Treatment: Irrigation, antibiotics, extraction

Acute Osteomyelitis

Causative Agent: Bacterial (after abscess, fracture, bacteremia); Transmission: Spread from infection; Oral Manifestations: Pain, swelling, pus, necrotic bone; Diagnosis: Radiograph, histology; Treatment: Drainage, antibiotics

Chronic Osteomyelitis

Causative Agent: Secondary to acute; Oral Manifestations: Same; Diagnosis: Diffuse radiolucency → radiopacity; Treatment: Debridement, antibiotics, hyperbaric O₂

Fungal Infections

Includes oral candidiasis, deep fungal infections (histoplasmosis, blastomycosis, cryptococcosis) which mimic SCC; biopsy needed

HPV-Related Lesions

Includes verruca vulgaris, condyloma acuminatum, focal epithelial hyperplasia (Heck's disease)

Herpesviruses

Includes HSV-1 (oral), HSV-2 (genital), varicella-zoster, EBV, and Coxsackievirus

Transmission of HIV

sexual, blood, mother → child

Stages of HIV

acute infection → latent → immunodeficiency (AIDS if CD4 <200)

Diagnosis of HIV

ELISA, Western blot

Oral manifestations of HIV

Includes oral candidiasis, hairy leukoplakia (EBV), Kaposi sarcoma, linear gingival erythema / NUG / NUP, recurrent herpes, aphthous ulcers, HPV lesions