Chapter 19: Allergy

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1

An abnormal or hypersensitive response of the immune system to a substance introduced into the body.

allergy

2

Allergic reactions account for about 6% to 10% of all adverse drug reactions. Which is the most common manifestation of drug allergy?

  1. fixed drug reactions
  2. anaphylaxis
  3. erythema and rash
  4. erythema multiforme
  5. urticaria

C. erythema and rash

  1. erythema and rash (46%)
  2. urticaria (23%)
  3. fixed drug reactions (10%)
  4. erythema multiforme (5%)
  5. anaphylaxis (1%)
3

Foreign substances that trigger hypersensitivity reactions.

antigens

4

The primary underlying factor in hypersensitivity reactions is aberrant regulatory activity of which cell type?

  1. T lymphocytes
  2. B lymphocytes
  3. basophils
  4. eosinophils
  5. neutrophils

A. T lymphocytes

5

Which cells recognize specific foreign chemical configurations and differentiate into memory cells and plasma cells?

  1. T lymphocytes
  2. B lymphocytes
  3. basophils
  4. eosinophils
  5. neutrophils

B. B lymphocytes

6

Which is the key antibody involved in the pathogenesis of type I hypersensitivity reactions?

  1. IgG
  2. IgA
  3. IgM
  4. IgE
  5. IgD

D. IgE

7

Which immunoglobulin is described by the following?

  • most abundant
  • small size
  • crosses placenta
  • opsonizing antibody
  • four subclasses

IgG

8

Which immunoglobulin is described by the following?

  • two types
  • secretory (dimer)
  • serum (monomer)
  • does not cross placenta
  • last to appear in childhood

IgA

9

Which immunoglobulin is described by the following?

  • large molecule
  • confined to intravascular space
  • first produced
  • activates complement
  • good agglutinating antibody

IgM

10

Which immunoglobulin is described by the following?

  • very low serum concentration (0.004%)
  • increased in parasitic and atopic diseases
  • binds to mast cells and basophils
  • key antibody in type I hypersensitivity

IgE

11

Which immunoglobulin is described by the following?

  • low concentration in serum
  • minor importance

IgD

12

Which of the following are NOT true regarding the PRIMARY response to an antigen?

  1. Antigen is processed
  2. B lymphocyte clone is selected
  3. Differentiation and proliferation
  4. Memory B cells produce specific immunoglobulins
  5. IgG level increases first, followed by IgM

D and E

PLASMA cells produce immunoglobulins, not memory cells (D). IgM increases first, followed by IgG (E).

13

Which of the following are NOT true regarding the SECONDARY response to an antigen?

  1. Antigen is processed
  2. Memory cells are selected; become plasma cells
  3. Plasma cells produce specific immunoglobulins.
  4. IgG levels increase first.
  5. IgG levels increase less than in primary response.

D and E

IgM levels increase first, not IgG (D). IgG levels increase MORE than in the first exposure, up to 50 times the level found in the primary response (E).

14

What type of hypersensitivity reaction is described by the following?

  • common exposures (e.g. insects, drugs, food)
  • IgE-mediated
  • release of histamine, leukotrienes, and interleukins
  • vascular dilation and smooth muscle contraction
  • hay fever, asthma, urticaria, angioedema, anaphylaxis
card image

type I hypersensitivity

15

This generalized urticarial reaction occurred after injection of penicillin for treatment of an acute oral infection. What type of hypersensitivity reaction is this?

type I hypersensitivity

16

An acute reaction involving bronchial smooth muscle in which antigen–IgE antibody complexes on the surface of mast cells results in histamine release, which may end in acute respiratory compromise and cardiovascular collapse.

anaphylaxis

17

A hypersensitivity state that is influenced by hereditary factors.

atopy

18

A superficial lesion of the skin associated with atopy.

urticaria

19

Edema that occurs in the dermis or subcutaneous tissues, often involving diffuse enlargement of the lips, infraorbital tissues, larynx, or tongue.

angioedema

20

Which type of angioedema is allergic (histamine) based?

acquired angioedema

21

Which type of angioedema results from impaired bradykinin degradation after administration of certain drugs?

drug-induced angioedema

22

Which type of angioedema is caused by a deficiency or dysfunction of complement C1 esterase inhibitor?

hereditary angioedema

23

What type of hypersensitivity reaction is described by the following?

  • IgG- or IgM-mediated
  • destruction of the targeted cells by complement
  • transfusion reaction caused by mismatched blood
card image

type II hypersensitivity

24

What type of hypersensitivity reaction is described by the following?

  • immune complex–mediated
  • excess antigen in the bloodstream
  • sets off the complement cascade
  • vasculitis, swelling, and pain
  • erum sickness, systemic lupus erythematosus
card image

type III hypersensitivity

25

What type of hypersensitivity reaction is described by the following?

  • delayed hypersensitivity
  • dermatitis, transplant rejection, graft-versus-host disease
  • sensitized CD4+ T lymphocytes release lymphokine
  • lymphokines promote a Th1 reaction mediated by macrophages
  • begins in hours and peaks in 2 to 3 days
card image

type IV hypersensitivity

26

A substance that is not antigenic by itself, but can form an antigenic complex if it comes in contact with a tissue component (primarily a protein).

hapten

27

Which of the following is a potential component of medical management of allergies?

  1. allergy injections
  2. moving
  3. steroids
  4. antihistamines
  5. all of the above

E. all of the above

  1. Patients with atopy may be given injections to gradually desensitize them.
  2. Patients with asthma may be forced to move to another area of the country.
  3. Patients with immune reactions may be treated with systemic steroids.
  4. Patient with hay fever or urticaria are treated with antihistamines.
28

Dental providers should be aware that about ___% of self-reports of allergy are not true allergies.

  1. 2%
  2. 5%
  3. 7%
  4. 10%
  5. 20%

B. 5%

29

What type of drug reaction is decribed by the following?

  • dose related
  • no immunologic basis
  • 80% of adverse reactions
  • direct toxicity
  • overdose
  • drug interaction
  • adverse effects of drugs

predictable (type A) reaction

30

What type of drug reaction is decribed by the following?

  • not dose related
  • unrelated to expected pharmacologic effects
  • allergy
  • pseudoallergy (anaphylactoid reactions)
  • idiosyncrasy
  • intolerance
  • paradoxical
  • underlying genetic defects

unpredictable (type B) reaction

31

A patient reports that they are allaergic to local anesthetic because last time they recieved it "it made my heart race." Which of that following are appropriate actions that should be taken by the dentist?

  1. explain to the patient the likely cause of the previous reaction
  2. aspirate before injection to avoid depositing solution intravenously
  3. limit the amount of solution to the recommended dose
  4. all of the above

D. all of the above

True allergic reactions to the local anesthetics (amides) used in dentistry are rare. If the patient reports a toxic or vasoconstrictor reaction, the dentist should

  1. explain the likely cause of the previous reaction,
  2. avoid injecting solution intravenously by aspirating, and
  3. limiting the amount of solution to the recommended dose

If the patient's history supports a fainting episode and not a toxic or allergic reaction, the dentist's primary task is to reduce the patient's anxiety.

32

What type of local anesthetics are the following?

  • procaine
  • tetracaine
  • benzocaine
  • procaine

esters

33

What type of local anesthetics are the following?

  • articaine
  • bupivacaine
  • lidocaine
  • mepivacaine

amides

34

A patient with an allergy to proparacaine requires local anesthetic for a dental procedure. Which of the following would be an appropriate choice?

  1. procaine
  2. benzocaine
  3. bupivacaine
  4. none of the above
  5. any of the above

C. bupivacaine

The benzoic acid ester anesthetics may cross-react with each other; if a patient is allergic to one ester, all esters should be avoided.

35

A patient with an allergy to articaine requires local anesthetic for a dental procedure. Which of the following would be an appropriate choice?

  1. lidocaine
  2. bupivacaine
  3. tetracaine
  4. none of the above
  5. any of the above

E. any of the above

Amide anesthetics are less likely to cross-react with each other; if a patient is allergic to one amide, another may be tolerable.

36

Which is the is the local anesthetic associated with the highest incidence of allergic reactions?

  1. lidocaine
  2. bupivacaine
  3. tetracaine
  4. procaine
  5. prilocaine

D. procaine

Cross-reactivity has been reported between lidocaine and procaine; however, this was traced to methylparaben, which previously was used as a preservative. Methylparaben is no longer used, so this problem is no longer a concern.

37

Which antihistamine can be used as a local anesthetic for patients who are allergic to local anesthetics but who cannot identify the specific allergen?

  1. acrivastine
  2. cetirizine
  3. diphenhydramine
  4. loratadine
  5. mizolastine

C. diphenhydramine

A solution of 1% diphenhydramine with 1 : 100,000 epinephrine induces anesthesia of about 30 minutes' duration and can be used for infiltration or block injection.

38

A 1% solution of diphenhydramine that contains 1 : 100,000 epinephrine can be used for infiltration or block injection, but no more than ___ mg should be given during a single appointment.

  1. 25 mg
  2. 50 mg
  3. 100 mg
  4. 200 mg

B. 50 mg

39

When administering an alternative anesthetic to a patient with a history of a local anesthetic allergy, what three steps should the dentist follow?

  1. Inject slowly, aspirating first.
  2. Place 1 drop of the solution into the tissues.
  3. Withdraw the needle and wait 5 minutes.

If an allergic reaction does not occur, the anesthetic can be delivered at the recommended dose for the procedure.

40

What is the most common cause of drug allergy?

  1. penicillins
  2. aspirin
  3. ibuprofen
  4. sulfonamides

A. penicillin

In the United States, about 5% to 10% of the population is allergic to penicillin and penicillin-related drugs.

41

A patient who requires prophylaxis against infective endocarditis self-reports allergy to penicillin. Which of the following would be the SAFEST alternative?

  1. erythromycin
  2. clindamycin
  3. cephalexin
  4. cefazolin
  5. A and B
  6. C and D
  7. any of the above

E. A and B

Cephalosporins are often used as alternatives to penicillins, but cephalosporins cross-react in 5% to 10% of penicillin-sensitive patients.

42

Cephaloyl, a major metabolite of cephalosporins, can cross-react with major determinant of penicillin (penicilloyl polylysine). Which of the following cephalosporins would be LEAST likely to exhibit cross-reactivity?

  1. cephaloridine
  2. cephalothin
  3. cephalexin
  4. ceftriaxone

D. ceftriaxone

The risk is greatest with first- and second-generation drugs such as cephaloridine (16.5%), cephalothin (5%), and cephalexin (5.4%).

43

Which of the following analgesics would be MOST appropriate for a patient with moderate pain and a history of hemorrhagic disease or peptic ulcers?

  1. asprin
  2. ibuprophen
  3. acetaminophen
  4. codeine
  5. any of the above
  6. none of the above

C. acetaminophen

Aspirin (A) and other NSAIDs (B) can cause gastrointestinal irritation and prolong bleeding time. They should be avoided in patients with hemorrhagic disease or peptic ulcers. Opioids (D) are not indicated for moderate pain.

44

Which of the following analgesics would be MOST appropriate for a patient with moderate pain and a history of asthma?

  1. asprin
  2. ibuprophen
  3. acetaminophen
  4. codeine
  5. any of the above
  6. none of the above

C. acetaminophen

Aspirin (A) and other NSAIDs (B) inhibit cyclooxygenase, the enzyme involved in generation of prostaglandin from arachidonic acid. This can provoke a severe reaction in some patients with asthma. Opioids (D) are not indicated for moderate pain.

45

Hereditary angioedema is a condition that can be provoked by infection, stress, trauma, or dental surgery. Which of the following are appropriate treatment options for hereditary angioedema?

  1. danazol
  2. stanozolol
  3. epinephrine
  4. antihistamines
  5. A and B
  6. C and D
  7. all of the above

E. A and B

Hereditary angioedema is caused by deficiency or dysfunction of complement C1 esterase inhibitor. Prevention is implemented by providing androgens such as danazol and stanozolol, which increase hepatic production of C1 inhibitor. Hereditary angioedema does NOT respond to epinephrine or antihistamines.

46

What type of hypersensitivity reaction if described by the following?

  • urticarial swelling or angioedema
  • rapid reaction after contact with antigen
  • painless swelling may cause itching and burning
  • can last for 1 to 3 days if untreated

type I hypersensitivity reaction

47

What is the treatment for type I hypersensitivity reaction NOT involving the tongue, pharynx, or larynx with NO respiratory distress?

50 mg diphenhydramine four times a day for 1 to 3 days

48

What is the treatment for type I hypersensitivity reaction involving the tongue, pharynx, or larynx with respiratory distress?

  1. 0.5 mL of 1 : 1000 epinephrine, IM or SC
  2. oxygen
  3. 50 mg diphenhydramine four times a day for 1 to 3 days
49
card image

Angioedema of the upper lip that occurred soon after injection of a local anesthetic. What type of hypersensitivity reaction is this?

type I hypersensitivity reaction

50

What type of hypersensitivity reaction is described by the following?

  • white, erythematous, or ulcerative lesions
  • related to immune dysfunction
  • develop within 24 hours of contact with antigen
  • includes erythema multiforme

type III hypersensitivity reaction

51

An immune complex reaction that appears as polymorphous eruption of macules, erosions, and characteristic “target” lesions that are symmetrically distributed on the skin or mucosa.

erythema multiforme

52

In about half of affected patients, a predisposing factor such as a drug allergy or a herpes simplex infection is involved in the onset of erythema multiforme. Which of the following are MOST likely to be associated with erythema multiforme?

  1. asprin
  2. ibuprofen
  3. sulfamethoxazole
  4. glipizide
  5. A and B
  6. C and D
  7. all of the above
  8. none of the above

F. C and D

Both sulfa antibiotics (C) and sulfonyl urea hypoglycemic agents (D) have been associated with the onset of erythema multiforme.

53

Some patients with skin or oral lesions identical to those of lichen planus will be found to be taking certain drugs that cause lichenoid reactions. Which of the following are associated with lichenoid drug reactions?

  1. levamisole
  2. quinidine
  3. thiazides
  4. methyldopa
  5. none of the above
  6. all of the above

F. all of the above

The agents most commonly associated with lichenoid lesions are levamisole and quinidine. Others include thiazides, gold, mercury, methyldopa, phenothiazines, and certain antibiotics.

54
card image

Stomatitis in a patient who was found to be allergic to the toothpaste he was using. What type of hypersensitivity reaction is this?

type III hypersensitivity reaction

55
card image

Allergic rash on the abdomen of a patient in whom orthodontic brackets and archwires were just placed. What type of hypersensitivity reaction is this?

type III hypersensitivity reaction

56
card image

Erythema multiforme that developed after oral administration of a drug used to treat an oral infection. What type of hypersensitivity reaction is this?

type III hypersensitivity reaction

57
card image

Contact stomatitis developed several days after delivery of a removable partial denture framework. What type of hypersensitivity reaction is this?

type IV hypersensitivity reaction

58

In handling the anaphylactic reaction, the dentist should remember that it has an allergic origin. What steps should be taken if the dentist suspects an anaphylactic reaction is occurring? (5)

  1. place the patient in a head-down or supine position
  2. make certain that the airway is open
  3. administer oxygen
  4. prepare to send for help
  5. support respiration and circulation
59

If an immediate type I hypersensitivity reaction has resulted in edema of the tongue, pharyngeal tissues, or larynx, the dentist must take additional emergency steps to prevent death from respiratory failure. What steps should be taken? (5)

  1. Activate emergency medical service
  2. Inject 0.3 to 0.5 mL of 1 : 1000 epinephrine IM or SQ
  3. Supplement with IV diphenhydramine 50 to 100 mg if needed
  4. Support respiration with mouth-to-mouth or bag and mask
  5. Check carotid or femoral pulse; if undetectable, initiate CPR
60

If vital signs are depressed or absent, inject 0.3 to 0.5 mL 1 : 1000 epinephrine IM into the thigh or tongue, repeating as needed every ___ minutes until EMS arrive.

  1. 3 minutes
  2. 5 minutes
  3. 10 minues
  4. 15 minutes
card image

B. 5 minutes