Allergy to Dental Materials & Drugs

• What are the 4 routes of entry for an allergen?

  Percutaneous/mucosa- plants/pet scratch

  Injection- bee stings

  Inhalational- hay fever (pollen), asthma (dust)

  Ingestion- food (nuts), medicines
• What is an allergy?

  An immunologically based sensitivity:

  
  

  Specific immune response to the allergen

  Not dose dependent

  Reaction will change on subsequent exposure
• What is toxicity?

  A non-immunologically based reaction:

  
  

  Non-specific, not immune

  Dose dependent

  May be accumulative

  Reaction will be similar on subsequent exposure
• What is hypersensitivity?

  A state of altered reactivity in which the body reacts with an exaggerated immune response to a foreign substance

  Hypersensitivity reactions are classified as immediate or delayed types I and IV, respectively, in the Gell and Coombs classification of immune responses
• What are the 4 types of hypersensitivity?

  Type 1–immediate IgE mediated: anaphylaxis

  Type 2–auto antibody mediated

  Type 3–immune complexes

  Type 4–T cell mediated: delayed hypersensitivity

  
• Describe a type I hypersensitivity reaction:

  -Mediated by IgE bound to high affinity Fc receptors on mast cells.

  
  

  -Cross linking of IgE/Fc receptor complex by antigen = degranulation + release of histamine, serotonin, proteases, cytokines etc

  
  

  -This activates and attracts eosinophils, neutrophils and macrophages

  
  

  -Leukotrienes + histamines = vascular permeability, smooth muscle contraction, and bronchoconstriction

  
• Describe a type II hypersensitivity reaction:

  -Auto-antibodies bind to antigens coating a target cell

  
  

  -This combination insights a chemical cascade which invokes the complement cascade.

  
  

  -Causes cytotoxic reaction which leads to cell damage

  
• Describe a type III hypersensitivity reaction:

  -Soluble antigens (from infection/persistent exposure to antigens) bind to antibodies (IgG/IgM) in excess or in the wrong proportions = immune complexes

  
  

  -Immune complexes circulate in blood and can be deposited in various tissues.

  
  

  -These can then activate complement cascade = production of chemotactic factors and recruitment of inflammatory cells.
• Describe a type IV hypersensitivity reaction:

  -Mediated by T cells

  
  

  -Activated T cells secrete chemokines, cytokines to recruit and activate macrophages

  
  

  -Activated macrophages secrete further pro-inflammatory cytokines, tissue damage from degranulation.

  
  

  -Formation of granuloma: including macrophages/multi-nucleated giant cells, eosinophils, T cells etc.

  
• What types of materials in dentistry could possibly induce an allergic reaction?

  Drugs:Local anaesthetics, cortico-steroids, antibiotics, analgesics (pain reliever)

  Restorative materials:Amalgams, ionomers, composites, metals & porcelains

  Clinical materials:Latex, impression materials

  Tooth paste/mouth washes
• Which drugs can cause reactions on your mucosa and what are their respective reactions?

  Corticosteroids- candidiasis

  Methotrexate- ulceration

  Gold- lichenoid reactions

  Penicillamine- loss of taste

  Antimalarials- lichenoid reactions

  NSAIDs- lichenoid reactions (rarely) oral ulceration

  
• What reactions can you get to toothpastes & mouthwashes?

  Toothpastes and mouthwashes:

  Gingival desquamation (loss of surface)

  Gingival swelling & granulomatous reactions

  Benign migratory glossitis

  Epithelial desquamation, inflammation

  Ulceration
• What reactions can you get to creams, ointments & impression materials?

  Creams, Ointments, Impression materials:

  Contact stomatitis

  Gingival desquamation, swelling & granulomatous reactions

  Mucosal Swelling

  Epithelial desquamation, inflammation

  Ulceration
• Are there lots of allergic reactions to LA?

  True allergy is rare and accounts for <1% of adverse reactions to LA

  
  

  True allergy may be delayed as well as immediate type
• Are there lots of adverse reactions to LA?

  LA account for 5-10% of adverse reactions to anaesthetics drugs, so it's not a lot, it's mainly GA to which there are more adverse reactions
• What are adverse effects to LA associated with?

  Blocking of ion channels in cell membranes (CVS and CNS toxicity)
• What are the main reasons of referral after using LA?

  Collapse after LA (immediate or 2 hours later) (25%)

  
  

  Swelling of lips, eyes, cheeks, face (immediate and up to 2 hours later) (25%)

  
  

  Rash on chest, limbs, or contact area (1-7 hours later) (15%)

  
  

  Breathlessness, sweating, nausea, disorientation (10%)

  
  

  Headaches, irregular pulse and low BP(8%)

  
  

  Swelling of throat, difficulty in breathing (8%)

  
  

  Behavioural changes (minutes to hours later) (5%)

  
  

  Sleepiness, dizzy (5%)
• Describe the experiment that was taken out to see reactions to scratch & intradermal challenge LAs.

  Scratch testing = skin prick test

  
  

  Intradermal = 25 macro-metres of LA is introduced beneath the skin

  
  

  Asthma, eczema and hay fever = atopic conditions

  
• What were the conclusions from the experiment?

  
• What can the Type IV hypersensitivity (contact hypersensitivity) reaction be seen in?

  Mantoux skin test

  
  

  Homograft rejection (when immune system rejects transplantation form another individual)

  
  

  It's thought that it could also be involved in orofacial granulomatosis
• What were the skin sensitisation figures (reactio to latex) for different health care professionals?

  Dentists: about 10%

  
  

  General hospital staff: 5-8%

  
  

  Nurses: 9%

  
  

  Anaesthetists: 16%

  
  

  Therefore, latex has mostly stopped being used in the dental clinics for gloves- it's normally latex-free

  
  

  Amalgam can also cause lichenoid reactions in Buccal mucosa

  
• How do you manage a latex allergy?

  Wear non latex gloves- plastic/polyvinyl-Sensitisation by contact, inhalation of protein dust, so reduce dust by use of powderless gloves

  Specific RAST test-Skin scratch test-70% have atopic history

  Avoid contact with latex at home & work-Patients advised to carry non latex gloves with them to hairdressers etc:)-Polyurethane condoms-Non rubber erasers etc.

  Dental Practices should have a latex allergy policy in place-Antihistamines-Some patients may need to carry Epipen
• What are some other causes of lip swelling?

  - Urticaria (hives) & Angioedema (swelling)

  
  

  - Reactions to foods (as part of type I reaction)

  
  

  - Granulomatous conditions affecting the lips & oral cavity (may possibly be type IV)
• What is urticaria?

  Commonly referred to as 'hives', characterised by wheals: spots or patches of raised red or white skin

  
  

  These usually clear away in a few hours, and are then replaced by other fresh wheals
• Are wheals painful?

  Yes, they're usually itchy, painful or cause a burning sensation
• What can urticaria sometimes occur together with?

  Angioedema
• What is angioedema?

  Name given to the deeper swelling affecting the skin over the arms, legs, torso or face

  
  

  May also affect the tongue, mouth, throat and sometimes the upper airway
• How long does the swelling usually last in angioedema and what is it usually associated with?

  Swellings commonly last for more than 24hrs, and usually there is no itching

  
  

  Often associated with autoimmune disease
• What are some causes of chronic angioedema?

  - Food allergy

  - Oral allergy syndrome

  - Medicine (ACE inhibitors, aspirin, beta blockers)

  - Antibiotics

  - Latex

  
  

  It is often not possible to identify the case of chronic angioedema

  
• Describe oral cavity reactions to foods.

  Not common but when they do happen, can be devastating.

  
  

  Usually type I reaction, although sometimes is type IV.

  
  

  The oral cavity is less sensitive than the skin/nose

  
  

  Peanuts is the most common food
• What other agents have been identified as causing problems in the oral cavity?

  Octyl gallate antioxidant preservative- sore tongue & erythema

  
  

  Pumpkin seed- swelling and asthma
• What happens in an immediate food allergy?

  It's a type I reaction so can result in anaphylaxis and only a small quantity of food is needed to trigger the reaction which develops in minutes to hours
• What are the symptoms of an immediate food allergy?

  Perioral erythema

  Lip swelling

  Oral itching

  Tongue & pharyngeal swelling

  Nausea & vomiting

  
• How does a delayed food allergy contrast with an immediate food allergy?

  Debate as to whether a delayed food allergy actually exists

  
  

  You need a large quantity of food for a delayed

  food allergy

  
  

  Develops in hours & weeks

  
  

  No diagnostic test for it except withdrawal & re-challenge
• Is food intolerance (non-allergic hypersensitivity) much more common than a delayed food allergy?

  Yes
• How does food intolerance differ from a delayed food allergy?

  -Onset of symptoms usually slower and delayed by many hours after eating the offending food

  
  

  -Symptoms may last for many hours, even into the next day

  
  

  -Intolerance to several foods or a group of foods is not uncommon, & it can be much more difficult to decide whether food intolerance is the cause of chronic illness, and which foods or substances may be responsible
• What are the symptoms of a delayed food allergy?

  Eczema

  Arthralgia (joint pain)

  Poor concentration/headaches/depression

  Irritable bowel syndrome/Crohn's disease

  Urinary frequency

  Arthritis & rhinitis
• What is oral allergy syndrome (pollen food syndrome)?

  Oral allergy syndrome (OAS) is a common food-related allergic condition that develops in adults.

  
  

  OAS is connected to environmental allergies, such as hay fever

  
  

  Distinctive type I reaction following direct contact of food and oral mucosa
• What do the features of oral allergy syndrome include?

  Swelling of mouth, periorbital tissues, pharynx
• What has the strongest association with oral allergy syndrome?

  Birch allergy

  Specific allergen Bet vI identified in birch and apple, most common foods associated with this are apples, peaches, kiwi, hazelnuts & almonds