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Allergies - Systemic

Signs and Symptoms Suggestive of an Allergic Reaction

  • Urticaria

  • Swelling

  • Skin rash

  • Chest tightness

  • Dyspnea, shortness of breath

  • Rhinorrhea

  • Conjunctivitis

Signs and Symptoms of a Toxic Reaction to Local Anesthetic 

  • Vasoconstrictor reaction is usually caused by excessive amount of local anesthetic used

  • Tachycardia

  • Apprehension

  • Sweating

  • Hyperactivity

Signs and Symptoms of a Vasoconstrictor Reaction

Signs and Symptoms of a Psychomotor Response to Injection of Local Anesthetic

  • Usually caused by anxiety about getting a "shot"

  • Hyperventilation

  • Vasovagal response (bradycardia, pallor, sweating)

  • Sympathetic stimulation (anxiety, tremor, tachycardia, hypertension)

Prevention 

A thorough review of the medical history, including questions specifically about the patient's response to substance.

References

Dental Management of the Medically Compromised Patient.  Little, Falace, Miller and Rhodus. 8th Edition

  • A toxic reaction is usually caused by inadvertent intravenous injection of the anesthetic solution or use of excessive amounts of local anesthetic solution

  • Talkativeness

  • Slurred speech

  • Dizziness

  • Nausea

  • Depression

  • Euphoria

  • Excitement

  • Convulsions

Introduction

The dentist is often confronted with problems related to allergy. Patients often have complaints of an allergy to analgesics, antibiotics and local anesthetic.   It is up to the dentist to determine if the patient's reaction is allergic or a negative reaction. 

Questions to ask the patient

  • What was your reaction to the substance?

Allergies to Common Medications

  • Penicillin

    • 1 in 10 people reports an allergy to penicillin, much fewer than 10% of these people actually are.

    • Possibility of sensitizing a patient to penicillin varies with different administration routes

      • Oral -  0.1% of patients

      • Intramuscular - 1-2%

      • Topical - 5-12%

  • Cephalosporins

    • ​15% of those that are allergic to penicillin are also allergic to cephalosporins 

    • An allergist can test for sensitivity

  • Local Anesthetics

    • True allergies to local anesthetics are extremely rare and usually due to the preservative in the anesthetic solution

      • Single dose vials and dental cartridges no longer include methylparaben (preservative)

        • Sulfites continue to be present in dental cartridges containing epinephrine or levonordephrin

        • Patients who are allergic to sulfa drugs (such as Bactrim) are NOT allergic to sulfites, which are common preservatives used in various foods as well as medicines 

        • For patients with a history of sulfite sensitivity use a plain anesthetic without vasoconstrictor

        • Sulfites are found in many types of foods

 

  • If the history supports an allergic reaction, and the patient knows the type of local anesthetic, an anesthetic from a different class can be used - there is no cross-allergenicity between the classes

    • Para-aminobenzoic acid (PABA) - esters such as procaine (Novocain) and tetracaine (Pontocaine)

    • Amides - lidocaine (Xylocaine), bupivacaine (Marcaine), articaine (Septocaine), mepivicaine (Carbocaine), prilocaine (Citanest)

      • There may or may not be cross-allergenicity between the different amide anesthetics

 

  • When administering an alternative anesthetic, inject slowly with aspiration. Place a drop of solution into the tissues.  Wait for 5 minutes.  If no allergic reaction occurs, as much anesthetic as needed can be injected.

 

  • If the type of anesthetic cannot be ascertained, the patient should be seen by an allergist for provocative dose testing (PDT) in addition to skin testing.  Send samples of your usual anesthetic agents without vasoconstrictors.

 

  • Diphenhydramine has been shown to induce anesthesia of about 30 minutes duration

    • A 1% solution of diphenhydramine that contains 1:100,000 epinephrine can be compounded by a pharmacist - be sure that methylparaben is not used as as preservative.

    • 1 - 4 mL is needed for a mandibular block

    • Side effects may include a burning sensation, swelling or erythema, but these are not serious and clear up within 1-2 days.

 

  • Analgesics

    • Aspirin - a significant number of patients have an allergy to aspirin

      • Also may cause GI upset (nausea, vomiting, dyspepsia) and heartburn

    • Other NSAIDs - should not be give patients with asthma or patients allergic to aspirin

      • These can casue allergic and non-allergic flares of hives/swellin, worsen asthma and result in anaphylaxis

      • May also cause GI irritation and heartburn

    • Codeine - most reactions are non-allergic

      • Vomiting, nausea, constipation

Summary of Signs and Symptoms of Allergy and Alternative Causes

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