Emergency - Allergic reactions

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					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!

				
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posted:12/16/2011
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Description: Medicine, Disease and Conditions