Allergy to Dental Materials Flashcards
4 routes of entry for allergens and most important routes in dentistry
1) Percutaneous//mucosa- Plants/Pet scratch
2) Injection- Bee stings
3) Inhalation- Hay fever (pollen) or Asthma (dust)
4) Ingestion- Food (nuts) medicines
Medicines through injestion
Mucosal entry
Both important in dentistry
Allergy and toxicity definition and difference
Allergy is an immunologically based sensitivity
- It is a specific immune response to the allergen
- It is not dose dependent
- Reaction will change on subsequent exposure (gets worse)
Toxicity is a non-immunologically based reaction or an intolerance
- It is non-specific and not immune related
- It is dose-dependent
- May be similiar on subsequent exposure
Hypersensitivity definition
- State of altered reactivity in which the body reacts with an exaggerated immune response to a foreign substance
- Classified as immediate or delayed types I and IV respectively, in the Gell and Coombs classification of immune responses
Time courses for various types of hypersensitivties
- Immediate hypersensitivity (Type I) takes place in the first hour
- Type III gives a late response (between 4-12 hours)
- Type IV hypersensitivity (delayed) occurs between 24-96 hours
Type I hypersensitivity definition, pathogenesis and examples
- Mediated by IgE bound to high affinity Fc receptors on mast cells
- Cross linking of the IgE/Fc receptor complex by antigen causes degranulation- release of histamine, serotonin, proteases, cytokines and leukotrienes
- Activates and attracts eosinophils, neutrophils and macrophages
- Leukotrienes, histamine induces vascular permeability, smooth muscle contraction, bronchoconstriction
Acute anaphylaxis
Hay Fever
Asthma
Urticaria (hives)
Type II hypersensitivity definition, pathogenesis
-Less common
- Mediated by IgG binding to a modified self antigen (penicillin-modified cell surface proteins) or a self antigen
- IgG Fc binds to Fc receptors of macrophages, NK cells
- IgG Fc also activates complement- opsonisation and activation of phagocytic cells
- Degranulation or phagocytosis (eg. of modified platelets)- tissue damage
- Associated with organ-specific disease (self antigen on tissue)
-Pemphigus
Type III Hypersensitivity definition and pathogenesis
- Mediated by IgG forming immune complex with soluble antigen
- Immune complexes deposit in blood vessels, synovial fluid and other tissues
- Activates complement and attracts neutrophils, macrophages and mast cells
- Action of complement and degranulation- tissue damage
- Associated with non organ-specific auto-immune disease
-Herpes and Erythema multiforme
Type IV Hyperpersensitivty
- Mediated by T cells (th1, Th17, Tc)
- Activated T cells secrete chemokines, cytokines to recruit and activate macrophages
- Activated macrophages secrete further pro-inflammatory cytokines (IL-12 and TNF) tissue damage from degranulation
- Formulation of a granuloma: macrophages/multi-nucleated giant cells, eosinophils, T cells, fibroblasts
- Associated with organ-specific autoimmune disease
-Lichenoid
Relevance of allergy in dentistry
- Dentist must know how to manage anaphylaxis
- Potential contact dermatitis
- Patients may have allergies
- May not know about the allergy
- Need to reduce exposure to potential allergens such as latex
Dental materials that can potentially cause allergic responses
Drugs
- Local anaesthetics
- Corticosteroids
Restorative materials
- Amalgam
- Ionomers
- Composites
Clinical materials
- Latex
- Impression materials
Toothpaste/mouthwash
Different drugs and mucosal reactions to them
Corticosteroids- Candidosis Methotrexate- Ulceration Gold- Lichenoid reactions Penecillamine- Loss of taste Antimalarials- Lichenoid reactions NSAIDs- Lichenoid reactions (rarely), oral ulceration
Drugs that can cause lichenoid reactions
- Nifedipine
- Sulfsalazine used in treatment of uc, arhtritis and crohns
Drug that can cause burn in the mouth
-Aspirin
Drug that can cause gingival hyperplasia
- Ca channel blockers (nifedipine)
- Phenytoin (Anti-epileptic)
- Cyclosporin (immunosuppresent)
Potential oral reactions to toothpastes and mouthwashes
- Gingival desquamation
- Gingival swelling and granulomatous reactions
- Benign migratory glossitis
- Epithelial desquamation, inflammation
- Ulceration
Potential oral reactions to creams, ointments, impression materials
-Contact stomatitis
-Gingival deaquamation
-Swelling and granulomatous reactions
-Mucosal swelling
-Epithelial desquamation
-Inflammation
Ulceration
Adverse reactions to LA
- Very rare
- Associated with blocking ion channels in membranes (CVS and CNS toxicity)
- Due to other effects of drug or vehicle (mainly peripheral nerve complications such as vasoconstriction in digits)
- Allergic reaction (often a mistaken diagnosis)
- Mechanical or other effects of technique such as needle trauma or introduction of infection
Reasons for referral after adverse reactions to LA
- Collapse (immediate or 2h later)
- Swellings of lips, eyes, cheeks or face
- Rash on chest, limbs or contact area
- Breathlessness, sweating, nasuea, disorientation
- Headaches, irregular pulse and low BP
- Swelling of throat
- Behaviour changes
- Sleepiness and dizzines
How would you test for a local anaesthetic allergy
- Initially try a scratch test
- Check if anyone is extremely allergic before giving an intradermal
- Scratch test didnt really differentiate between those who had an allergy and those who didn’t
- During intra-dermal testing, it was found that most people, if allergic, reacted to the prilocaine
- Perhaps this is because of the plastic encasing
- Scratch skin tests alone are not good discriminators of allergy, intradermal are better discriminators
- Lidocaine produced more positive skin reactions than any other local anaesthetic agent tested (prilocaine was due to plastic casing)
- Negative skin reactions to at least one of the agents means that that agent can be recommended for intrabuccal agents for future use
Patch Testing definition
- Patches left in place for 48 hours
- Hypo-allergic paper
- Number of different allergens
- Read at 48th hour and 96th hour
- Check to see which allergens produced a response
Clinical manifestations of urticaria
- Hives
- Wheals- spots or patches of raised red or white skin
- Usually clear away in a few hours, and are replaced by other fresh wheals
- Itchy, painful or cause a burning sensation
- Sometimes occurs together with angiodema
Angiodema definition and clinical manifestations
- Swelling of the soft tissues
- Fluid from blood vessels into tissue
- Angiodema is the name given to deeper swelling affecting the skin over the arms, legs, torso or face
- May also affect the tongue, mouth, throat and sometimes the upper airway
- Swellings commonly last for more than 24 hours, and usually there is no itching
Causes of chronic angiodema
Food Allergy (particularly nuts, shellfish, milk and eggs)
Oral Allergy Syndrome
Medicines
- Antibiotics
- ACE inhibitors (ramipril, enalopril, lisinopril)
- Angiotensin 2 receptor blockers (Losartan)
- Aspirin and NSAIDs
- Beta Blockers
Latex
Hereditary (C1 Esterase Inhibitor Deficiency)
-Attacks triggered by-stress/injury/surgery/dental treatment/pregnancy/medications
-Often not possible to identify cause of chronic angiodema
Reactions to latex and management , investigations
-Dental school staff and students are at high risk of sensitzation to latex
- Use non-latex gloves: plastic or polyvinyl
- Sensitisation by contact, inhalation of protein dust so use powderless gloves
- Specific RAST test
- Skin scratch test
- 70% have atopic history
- Avoid contact with latex at home and work
- Patients are advised to carry non latex gloves with them to the hairdressers etc
- Polyurethane condoms
- Non rubber erasers
- Dental practices should have a latex allergy policy in place
- Antihistamines
- Some patients may need to carry an Epipen
Oral Cavity reactions to food
- Usually type 1, sometimes type 4
- Oral cavity less sensitive than skin or nose
- Peanuts most common
- Pumpkin seeds lead to swelling and asthma sometimes
- Octyl gallate oxidant preservative can lead to sore tongue and erythema
Immediate food allergy definition and clinical features
Type I Hypersensitivity reaction
-Anaphylaxis
- Perioral erythema
- Lip swelling
- Oral itching
- Tongue and pharyngeal swelling
- Nausea and vomiting
- Reaction develops in minutes to hours
- Diagnostic skin tests available
Delayed food allergy and symptoms
- Don’t really know if it exists
- Coeliac disease and dermatitis herpetiformis well-established
- Large quantity of food needed
- Develops in hours and weeks
-No diagnostic test except withdrawal and rechallenge
Food intolerances much more common
- Exzema
- Arthralgia (achy joints)
- Poor concentration/headaches/depression
- IBS/ Crohn’s
- Urinary frequency
- Arthrits and rhinitis
Food intolerances
- Food intolerances (non allergic hypersensitivity) are much more common nowadays than delayed food allergies
- Onset of symptoms is usually slower and may be delayed by many hours after eating the offending food
-Can be difficult to decipher which foods are causing the tolerance
Oral manifestations of food allergy
- Oral pruritis
- Taste changes
- Perioral rashes
- Fissured tongue
- Facial swelling
- Buccal lip swelling
- Erythema
- Burning mouth
- Gingivo-stomatitis
- Orofacial-granulomatosis
- Orodynia
- Oral ulceration
- Erythema migrans
Oral Allergy Syndrome/Pollen Food Syndrome definition
- Type of food allergy classified by a cluster of allergic reactions in the mouth and throat in response to eating certain fruits, nuts and vegetables
- Pollen allergens for example tree birch
- Adults>Children
- Usually occurs in people allergic to pollen from trees, grasses and weeds
- Proteins of similiar structure in fruit
- Distinctive type 1 reaction following direct contact of food and oral mucosa
Clinical features of AES and common allergens
- Swelling of the mouth, peri-orbital tissues and pharynx
- Birch allergy strongest association, 20% may be scratch positive to apples, peaches, kiwifruit and almonds
- Antigens are inactivated by cooking
Guidelines for management of allergic reactions
-Establish provisional diagnosis
What it is the allergen
Previous history of reaction- mild/severe
Onset- rapid/delayed- how soon after contact
Type of symptoms- rash, oedema, conscious level, breathing difficulties and oral ulcers
-Previous management of reaction
None, medication or hospitalisation
-Investigations
Investigations of Type I and IV hypersensitivities
Type I
- allergy testing- scratch test/intradermal/intrabuccal
- Check for oedema
Serology
- Mast cell tryptase levels
- Complement
Routine blood tests
- FBC
- B12
- Folate
- Ferritin
Type IV:
Allergy testing- patch tests
Complementary and alternative allergy testing
- Leukocytotoxic Test
- IgG Elisa Test
- Kinesiology
- VEGA testing
- Hair analysis
- Auriculo-cardiac reflex
- stools test
Management of patients
-If allergy not proven with allergy testing, clear types letter to referrer of findings and diagnosis
-If allergy proven, give information to patient on proven allergens identified
Consider advice such as stay away
-Prophylactic antihistamines/corticosteroids
Fexafenadine
Prednisolone
Adrenaline
