ALLERGIC REACTIONS in the DENTAL OFFICE

Allergic Reactions Allergy is defined as a hypersensitive state aquired through exposure to a particular allergen, reexposure to which produces a heightened capacity to react

Allergic Reactions Allergic reactions range from mild, delayed reactions occuring as long as 48 hours after exposure, to immediate life-threatening reactions that occur within seconds after exposure

Classification of Allergic Reactions Type Mechanism Time Example I Anaphylactic sec/min Angioedema II Cytotoxic -- Transfusion rx III Immune 6-8hrs Serum sickness complex IV Cell mediated 48 hrs Contact dermatitis

Most Common in Dental Office Type I  Immediate Localized or Generalized Anaphylaxis - The Type I allergic reaction is subdivided into several forms based upon the response Type IV Contact Dermatits

Type I Immediate Hypersensitivity Generalized (Systemic) Anaphylaxis Localized Anaphylaxis Urticaria Bronchial Asthma Food Allergy

Antigen A substance that elicits an allergic reaction

Antibody A substance in blood or tissue that responds and reacts with the antigen (different in structure than the antigen)

Atopy Clinical hypersensitivity state, subject to heredity (asthma, hay fever, etc.)

Urticaria Wheals (hives) Smooth elevated patches surrounded by erythematous areas Pruritus (itching)

Angioedema Non-inflammatory edema involving skin, subcutaneous tissue, underlying muscle & mucous membranes. Occurs in response to allergen Most critical in the larynx

Predisposing Factors in Allergic Reactions Prior history of allergy Genetic predisposition to allergy - atopic patient Patient with multiple allergies Drug that is utilized

Drugs that Cause Allergic Reactions Up to 70% of Allergic Reactions Penicillin Meprobamate Codeine Thiazide Diuretics

Other Substances Causing Reactions Iodines Vaccines Insulin Heparin Salicylates Sulfonamides Opiates Local Anesthetics Venom from stinging insects

Antibiotic Allergy Highest incidence Penicillins (anaphylactic reaction may prove fatal in 15 minutes) Sulfonamides Reactions to erythromycins rarely seen

Analgesic Allergy Incidence of true allergy to narcotics is low "Allergy" is most often a side effect such as nausea, vomiting, drowsiness, dysphoria, or constipation

Antianxiety Drug Allergy Barbiturates -most common but occur less than aspirin and penicillin Reactions -hives, urticaria, blood dyscrasia (agranulocytosis / thrombocytopenia) Allergy occurs more frequently with a history of asthma, urticaria, and angioedema

Local Anesthetics Reactions occur most frequently with Esters Preservatives also cause reactions

Ester Drugs Procaine Propoxycaine Benzocaine Tetracaine Related compounds Procaine Penicillin G Procainamide

Amide Allergy The amide type anesthetic are essentially free of allergic reaction when given in their pure form Although true allergy to amide type anesthetic is extremely rare, patients have demonstrated allergic reaction to the contents of the dental cartridge

Ingredient - Function Anesthetic Agent - Conduction blockade Vasoconstrictor - Decrease absorption of local anesthetic Sodium Metabisulfite - Preservative for vasoconstrictor Methylparaben - Preservative to increase shelf life; bacteriostatic Sodium Chloride - Isotonicity of solution Sterile Water - Diluent

Paraben Reactions Preservative found in many non-drug items Allergic reactions to topical anesthetics are those of contact stomatitis; erythema, edema, ulcerations - almost exclusively a dermatologic type reaction

Clinical Options Determine type of “allergic” reaction Substitute different drugs for those which cause the allergic reaction. Have patient evaluated by allergist

Management of Allergic Reactions Most severe allergic reactions are immediate A number of organ oystems may be involved Skin Cardiovascular Respiratory Gastrointestinal

Management of Allergic Reactions Generalized anaphylaxis involves all of the previously mentioned systems When hypotension occurs, it is termed Anaphylactic Shock

Affected Area - Manifestation Skin Urticaria-Wheal & Flare pruritis, angioedema, erythema Respiratory Dyspnea,wheezing,flushing, cyanosis,perspiration,tachycardia, increased anxiety,use of accessory muscles of respiration

Affected Area - Manifestation Gastrointestinal Abdominal cramps, nausea, vomiting, diarrhea, incontinence Cardiovascular Pallor, light-headedness, palpitations, tachycardia, hypotension, dysrhythmias, loss of consciousness, arrest

Sequence of Reaction 1. Skin reaction 2. Smooth muscle spasm (GI, GU, and bronchial) 3. Respiratory distress 4. Cardiovascular collapse

Type of Reaction Quick Onset==> Rapid Progression==> Intense Reaction Delayed Onset==> Slow Progression==> Less Severe Reaction

Drugs Used in Allergic Reactions

Epinephrine Has Alpha and Beta adrenergic effects Acts as a physiologic antagonist to the events that occur during an allergic reaction

Epinephrine Actions Include Bronchodilation Increased heart rate Arterial constriction Cutaneous, mucosal, and splanchnic vasoconstriction Reverses rhinitis and urticaria

Epinephrine Risks of repeated use: Excessive elevation of blood pressure CVA Cardiac rhythm abnormalities

Antihistamine Benadryl (chlorpheniramine) most often used H-1 blocker Inhibits action of histamine released during reaction to allergen

Corticosteroids Hydrocortisone used most often Stablilizes cell membranes against actions of histamines, bradykinins, and prostaglandins Supplements adrenal steroid output during stress

Treatment of Immediate Skin Reactions Epinephrine 0.3 mg IM or SC (0.3ml of a 1:1000 Solution) Antihistamine Diphenhydramine (Benadryl) 50 mg IM

Treatment of Immediate Skin Reactions Obtain medical consultation Observe patient for at least one hour Prescribe oral antihistamines Benadryl 50 mg PO Q6H for 3-4 days

Treatment of Delayed Skin Reactions Antihistamine Diphenhydramine (Benadryl) 50 mg IM Prescribe oral form Q6H for 3-4 days Arrange medical consultation

Treatment of Respiratory Reactions Bronchial Constriction Terminate dental treatment Sit patient upright Oxygen 6 L/min Epinephrine aerosol or 0.3 mg IM or SC (0.3 ml of a 1:1000 solution)

Treatment of Respiratory Reactions Bronchial Constriction (cont.) Observe for at least 1 hr Antihistamines - Benadryl 50 mg IM Obtain medical consulatation Prescribe oral antihistamines (Q6H for 3-4 days)

Treatment of Respiratory Reactions Laryngeal Edema Sit patient upright Epinephrine 0.3 mg IM or IV Maintain airway Summon medical assistance

Treatment of Respiratory Reactions Laryngeal Edema (cont.) Oxygen 6 L/min Cricothyroidotomy Additional drug therapy Diphenhydramine 50mg &/or Hydrocortisone 100 mg

Generalized Anaphylaxis with Signs of Allergy Place patient in a supine postion Basic Life Support (ABCs) Administer epinephrine 0.3 mg IM or SC (0.3 ml of a 1:1000 solution) Summon medical assistance - call 911

Generalized Anaphylaxis with Signs of Allergy Monitor vital signs Additional drug therapy Antihistamines Corticosteroids Repeat epinephrine Q5min prn

Generalized Anaphylaxis without Signs of Allergy Place patient in a supine position Basic Life Support Monitor vital signs Summon medical assistance prn

Generalized Anaphylaxis without Signs of Allergy Consider possible causes of unconsciousness Syncope Overdose Reaction Hypoglycemia CVA Acute Adrenal Insufficiency

Prevention of Allergic Reactions HISTORY - a thorough, complete history of any previous allergic response or tendency prior to starting treatment will avoid most emergencies

Other Means of Prevention Medical consultation Dental office skin testing (not foolproof and not advisable)

Take Home Lessons All positive responses to an allergy history are true until exact nature is determined! Patients reporting allergies should be critically evaluated -refer for allergy testing if history, reaction, or management are suspect. Be prepared to manage difficulties! Always!