Allergic Reactions in the Dental Office

Allergy definition

A hypersensitive state acquired through exposure to a particular allergen-Re exposure produces a heightened capacity to react

Antigen definition

Any substance, but usually a foreign protein, capable of inducing antibodies

Allergen definition

An antigen that elicits an allergic reaction

Hapten definition

A protein-free substance that can combine with a host protein and elicit an immune response

Most common antibody and allergic reaction in a dental office

IgE and type 1

Types of Allergic Reactions

-The allergic reactions of most concern in the dental office are IgE mediated Type 1 reactions.-However, for a patient having an allergic reaction in the dental office, it is not crucial to identify the specific type of allergic reaction.

Most important things to identify about an allergic reaction

It is more important to identify:-The severity of the reaction-The speed of onset of the reaction-The extent of the reaction (localized or generalized)

Allergic Reactions - Physiology

-Previous exposure to a foreign antigenic substance caused antibody formation-Subsequent exposure elicits a heightened antigen-antibody immune response-Many reported "allergic" drug reactions are not truly allergic

Physiologic Systems Involved in Allergy: Skin

erythema, urticaria, wheals, rash, pruritus

Physiologic Systems Involved in Allergy: Respiratory

bronchospasm, laryngeal edema

Physiologic Systems Involved in Allergy: GI

Nausea/vomiting, abdominal pain/cramping

Physiologic Systems Involved in Allergy: Cardiovascular

-capillary dilation and increased permeability (angioedema)-hypotension-lightheadedness-tachycardia (anaphylactic shock)-loss of consciousness

Potential Allergens in the Dental Office

1. Local anesthesia-Amides vs. esters-Sodium bisulfite (anti-oxidant for vasoconstrictor) → sulfite allergy?-Actually a stress reaction or effect of vasoconstrictor?2. Antibiotics (Penicillins, Cephalosporins, Sulfa drugs, etc.)3. Latex4. Pain medications (allergy vs. side effect)

Dental patients at relative risk for an allergic reaction

1. Patients with a known prior allergic reaction to specific agent-Patients may demonstrate cross reactivity to medications of a similar chemical structure2. Atopic patients3. All patients!

For patients with know allergies to medications, the dentist should determine:

-The specifics of previous reaction-The timing of the event-The required treatment

Precipitating Factors

Contact with a substance to which the patient has been previously exposed and to which antibodies have been made, thus sensitizing the patient

Allergic Reactions - Prevention

-Care in prescription writing-Avoid prescribing medications in the same class as those to which known allergy exists-Route of administration: oral vs. injected(injected medications will can cause more rapid and severe allergic reactions)-Avoid exposure to know allergens (e.g. use of vinyl gloves in patients with latex allergies)

Allergic Reactions - Recognition

-Timing of the reaction: immediate vs. delayedImmediate→seconds to hourDelayed→hours to days(In general, the more rapid the onset, the more intense and severe the reaction will be, and visa versa.)-Extent of the reaction (rash, swelling, respiratory compromise, cardiovascular compromise)

Treatment: Delayed onset skin reaction

-Stop dental treatment-Assess respiration and blood pressure-May consider observation if localizedIf more generalized, diphenhydramine (Benadryl) 25 - 50 mg po TID x 3 days

Treatment: Immediate skin reaction

-Stop dental treatment-Assess respiration and blood pressure-Diphenhydramine 25 - 50 mg IM / IV-Continue to monitor vital signs-Rx for diphenhydramine 25 - 50 mg po TID x 3 days-Escort home (because of side effects)

Treatment: Respiratory or cardiovascular compromise

-Stop treatment-Phone 911-Position patient upright if having problems breathing-Position supine (if trouble breathing or trendelenberg (if hypotensive)-Oxygen-Epinephrine .3 - .5 mg SC / IM-Can repeat every 5 minutes if symptomspersist and V.S. permit-Bronchodilator inhaler if wheezing present-Diphenhydramine 25 - 50 mg IM / IV-Hydrocortisone 100 mg IM / IV-Basic life support as indicated-Intubation / cricothyrotomy