Lecture 5 Flashcards
What is an Antigen/Allergen?
Noninfectious foreign substance
What is an Allergy?
Hypersensitive response of the immune system to a substance introduced into the body
What is a Pseudoallergy?
Chronic urticaria (skin rash) caused by certain drugs, temperature changes, and emotional states, and in some reactions to drugs
What is Anaphylaxis?
Acute reaction involving smooth muscle of the bronchi. Mast cells release histamine → smooth muscle contraction → acute respiratory compromise and cardiovascular collapse
What is Angioedema? What parts of the face does it usually affect?
Edema that occurs in deep layers of tissues and often involves lips, tongue, infraorbital tissues, and larynx.
What does IgE have to do with hypersensitivity reactions?
Key antibody involved with type I hypersensitivity reactions.
What are Mast cells?
Cells that release histamine during allergic reactions.
What is an allergy?
A hypersensitive reaction to an ordinarily harmless substance.
What is the majority of allergies caused by?
Environmental factors.
Name some common environmental allergens.
Dust, pollen, latex.
What are some common food allergens?
Peanuts, tree nuts, shellfish, milk, eggs, wheat.
What are some common allergens related to insect stings?
Insect stings.
What medications are common allergens?
Aspirin, NSAIDs, penicillin, radiographic contrast media.
What are common allergens found in the dental office?
Latex gloves, glutens in some dental materials, some fluoride varnishes (pine nut allergies), preservatives in local anesthetics.
What is the initial exposure to an allergen called?
Sensitizing dose
What activates the body’s immune response during the initial exposure?
Initial exposure to antigen
Which antibody is produced in response to an allergen?
IgE
Where does IgE attach in the body?
Mast cells and basophils
What happens to IgE after it attaches to mast cells and basophils?
It lies dormant until the body encounters the antigen again
What is the term for the subsequent exposure to the same allergen?
Challenge dose
Where are mast cells and basophils found in the body?
Lungs, small intestine, and connective tissue
What occurs when the antigen is encountered again (challenging dose of a hypersensitivity reaction) ?
Mast cells and basophils undergo degranulation
What do mast cells and basophils release during degranulation?
Chemical mediators to destroy the allergen
What initiates the allergic reaction?
Degranulation of mast cells and basophils
What is the result of secondary exposure to the same allergen?
An allergic reaction occurs
What happens when the allergen binds to antibodies on mast cells?
Histamine is released
Signs and symptoms of an allergy
Are true allergies to local anesthetics used in dentistry common?
True allergies to local anesthetics used in dentistry are rare.
What reactions can occur due to preservatives in anesthetics?
Reactions to parabens (preservatives) such as sulfites can occur.
What is commonly mistaken for an allergy when receiving an injection?
A nervous reaction to receiving an injection is commonly mistaken for an allergy.
What symptoms may indicate anxiety during an injection?
Symptoms include hyperventilation, paleness, sweating, tachycardia, and syncope.
Why is it important to question the patient about their reaction?
It is important to determine if a true allergy exists.
What can anesthetics that contain epinephrine cause?
They may cause tachycardia, sweating, and paleness.
What is the reaction to epinephrine?
The symptoms are a reaction to epinephrine.
How should a dentist address a patient’s anxiety?
Explain to the patient and use techniques to decrease anxiety.
What should you do when a patient has an antibiotic allergy?
Question the patient about reaction symptoms.
What is a common antibiotic allergy?
Penicillin is a common antibiotic allergy.
Is there a risk of cross-reactivity with cephalosporins for patients with penicillin allergy?
Yes, there is a small percentage of patients with cross-reactivity to cephalosporins.
What should be prescribed if a patient has a penicillin allergy?
Another antibiotic such as erythromycin or clindamycin should be prescribed.
What are common analgesia allergies?
Aspirin and codeine.
What is a common side effect of aspirin?
Causes gastrointestinal upset.
What should be done when a patient reports they have an allergy to codeine?
Question the patient to determine true allergy or reaction. Sometimes reactions are severe enough to warrant an alternative agent.
What types of hypersensitivity reactions are involved in allergy to dental materials?
Type I, III, and IV hypersensitivity reactions
Name some common dental materials that may be allergens
Topical anesthetic, mouth rinses, hand soap, dentifrices, and flavoring agents added to dental materials
What dental metals like Composite, gold, nickel, mercury and restorative materials are associated with what type of hypersensitivity reaction?
Type IV reactions
What should be used instead of latex when possible? What other things other than latex gloves may contain latex?
Nitrile gloves, BP cuff, rubber dam, stopper in anesthetic cartridge
What are the presentations of allergy to dental materials?
Contact stomatitis, lichenoid reaction
What is hereditary angioedema?
A condition provoked by infection, stress, dental surgery, or trauma.
How is hereditary angioedema best managed?
By implementation of preventive measures.
How does hereditary angioedema respond to epinephrine or antihistamines?
It does not respond well to epinephrine or antihistamines.
What is a common systemic treatment for allergies?
Systemic steroids
What is an example of an antihistamine available over the counter?
Diphenhydramine (Benadryl)
What is the dosage of Diphenhydramine HCI in Benadryl tablets?
25 mg
Who should you consult for allergy testing?
Allergist
What are allergy skin tests used for?
To identify allergic reactions
What is the first step in dental management of allergies?
Thorough medical history questionnaire and documentation of allergens
What should be avoided when providing care to allergic patients?
Allergens
What should be included in the emergency drug kit for patients with allergies?
Drugs that can abort an allergic reaction
What position should the patient be placed in during an allergic reaction?
Head-down or supine position
What is the first actions to take during allergic reactions ?
Sit patient supine, Open Airway (A), administer O2, send for help and report respiration (B) and circulation (C)
What should be initiated if the allergic reaction is unresolved?
Emergency medical service (EMS) for anaphylaxis
What medications should be administered in case of anaphylaxis?
Epinephrine and Diphenhydramine
Type 1,3,4 HSR causes, symptoms, onset, duration and treatment
Allergic reactions range from
mild symptoms to life-threatening.
What are mild symptoms of allergic reactions?
Mild symptoms include rash, sneezing, watery eyes, runny nose, and skin irritation.
What are severe symptoms of allergic reactions?
Severe symptoms include severe hypotension, dyspnea, and are often referred to as anaphylaxis.
What is another term for anaphylaxis?
Anaphylaxis is also known as anaphylactic shock.
What factors determine the severity of an allergic reaction?
Severity is dependent upon the amount of allergen, rate of exposure, and route of exposure.
What percentage of the world’s population is dies from anaphylactic shock ?
15%
How many deaths annually in the United States are due to allergies?
1,500 deaths
Who is more likely to experience death from allergies?
Older individuals and females due to cardiovascular collapse and respiratory arrest
SEQUENCE OF VASCULAR EVENTS IN ANAPHYLACTIC
SHOCK
What are the signs and symptoms of an allergy?
Variable and tend to develop gradually.
Begin with pruritis of gingiva, throat, palms of hands and soles of feet
Urticaria - rash/hives
Angioedema - swelling under the skin, triggered by an allergy
May begin with cardiovascular, respiratory, or Gl symptoms
Do all signs and symptoms of an allergy present simultaneously?
No, not all signs and symptoms present simultaneously, and some may not be present at all.
BIPHASIC REACTION
• Occasionally, once the initial allergic symptoms have been resolved, the symptoms may recur
• This is referred as biphasic anaphylaxis
• Usually occurs within 3-10 hours but may occur 1-72 hours after successful treatment and resolution of initial response
• More likely if allergen ingested
• Second episode may be more severe
What factors determine the appropriate treatment for an allergic reaction?
The treatment depends on the severity of the reaction.
What should be done if the causative agent of the allergic reaction is known?
An attempt should be made to remove the causative agent if possible.
What are the common symptoms of a mild allergic reaction?
Mild reactions may include localized redness or itching in the area of inoculation.
How do mild allergic reactions usually progress?
They often appear self-limiting, meaning they resolve on their own without significant intervention.
What is the recommended first step in managing a mild allergic reaction?
Administering an oral histamine blocker is recommended.
How should a patient with a mild reaction be positioned, and why?
The patient should be placed in a supine position (lying down) and observed for worsening symptoms.
What is a common oral antihistamine used to treat allergic reactions?
Benadryl (oral diphenhydramine) is commonly used.
What is the recommended dosage for Benadryl?
The dosage is 25–50 mg every six to eight hours for three days.
What is another antihistamine option besides diphenhydramine?
Chlorpheniramine is another option.
How is chlorpheniramine typically dosed for allergic reactions?
It is given as 4 mg every four to six hours as needed.
How does chlorpheniramine compare to diphenhydramine in terms of side effects?
Chlorpheniramine causes less drowsiness than diphenhydramine.
What should be done after administering antihistamines for a mild allergic reaction?
The patient should be kept in a supine position and observed for worsening symptoms.
When does an allergic reaction become moderate?
When symptoms begin to spread and become more systemic.
What are some symptoms of a moderate allergic reaction?
Symptoms may include urticaria (hives) on the arms, face, and chest, severe pruritus (itching), and some edema (swelling) of the lips.
What vital signs indicate that the allergic reaction is still moderate rather than severe?
If the patient’s blood pressure, pulse rate, and respirations remain within the normal range, the reaction is considered moderate.
What is the recommended medication for a moderate allergic reaction?
An injection of diphenhydramine (Benadryl) 50 mg IM (intramuscular) is beneficial.
What additional medication should be considered if not already given?
An oral histamine blocker should be provided if not already dispensed.
Why is it important to monitor vital signs during a moderate allergic reaction?
To detect any signs of worsening symptoms that may indicate progression to a severe reaction.
How should oxygen be administered to a patient experiencing a moderate allergic reaction?
If indicated, oxygen should be given at a flow rate of 4–6 liters per minute.
How long should a patient with a moderate allergic reaction be observed?
For at least one hour to ensure that signs and symptoms do not worsen.
What is the role of epinephrine in severe reactions?
Epinephrine reverses the immediate symptoms of anaphylaxis.
What symptoms can epinephrine help alleviate?
Dyspnea, hypotension, and laryngeal edema.
What effects does epinephrine have on the body?
Reverses vasodilation, reduces edema, induces bronchodilation, and has a positive inotropic and chronotropic effect on the heart.
What should be done if allergic reaction symptoms worsen ?
Contact EMS.
How should epinephrine be administered?
Administer epinephrine IM .3 mL 1:1,000 in the quadricep muscle.
What is the protocol if there is no improvement after the first dose of epinephrine?
Repeat dosage after five minutes if no improvement.
What is the maximum number of doses of epinephrine that can be administered?
Max three doses.
What should you do while administering the epinephrine injector?
Hold the injector in place for 10 secs and hold the correct end to avoid injecting yourself.
What should be done after administering the injection?
Massage the injection site.
What is a common cause of fatalities in anaphylaxis treatment?
Most fatalities occur when epinephrine was administered too late.
What is the standard dosage of epinephrine in an autoinjector?
Available in autoinjector .3 mg 1:1,000.
How many autoinjectors should be available for epinephrine administration?
Should have two autoinjectors available or a vial of epi 1:1,000 with a syringe.
What should be monitored during treatment for anaphylaxis?
Monitor vital signs.
What steroid should be administered IM for treatment of anaphylaxis? When are the benefits realized?
Administer steroid IM (hydrocortisone succinate 100 mg).
Its benefit will not be realized until 6-12 hours after administration.
What histamine blocker should be administered IM for moderate to severe allergic reactions? This should be given to___
Administer histamine blocker IM (diphenhydramine 50 mg).
This should be given to alleviate the symptoms caused by the release of histamine, such as pruritus/itching.
What should be monitored for after treatment for anaphylaxis ?
Monitor patient for biphasic reaction.
Where should patients be referred after treatment for anaphylaxis?
Refer to ED.
After epinephrine is administered, patients suffering from an allergic reaction should be placed and remain in a
supine position, with their legs elevated in an attempt to increase their blood pressure; However, if patients are having severe breathing difficulty, an upright position may be beneficial to aid respiration
There is some evidence that a change in position from supine to sitting or sitting to standing can exacerbate the allergic symptoms and can be fatal because of the change in the blood flow
Positioning the patient supinely with the legs elevated ensures that the vena cava remains the lowest part of the body
