Question 1

Which of the following local anesthetics is associated with the highest incidence of allergic reactions?&#10;A) articaine (Septocaine)&#10;B) procaine (Novocain)&#10;C) lidocaine (Xylocaine)&#10;D) prilocaine (Citanest)

Accepted Answer

Procaine is the local anesthetic associated with the highest incidence of allergic reactions.Currently,it is available in multidose vials.Its antigenic component appears to be PABA,one of the metabolic breakdown products of procaine.Cross-reactivity has been reported between lidocaine and procaine; however,this potentially was due to the presence of a germicide,methylparaben,which previously was used in small amounts as a preservative and is chemically similar to PABA.Methylparaben is no longer used as a preservative,so this problem is no longer a concern.

Question 2

Which of the following is a clinical example of a type III hypersensitivity reaction?&#10;A) anaphylaxis due to penicillin allergy&#10;B) transfusion reaction caused by mismatched blood&#10;C) systemic lupus erythematosus&#10;D) contact dermatitis

Accepted Answer

Clinical examples of type III hypersensitivity reactions include systemic lupus erythematosus and streptococcal glomerulonephritis.Anaphylaxis due to penicillin allergy is an example of a type I hypersensitivity reaction.The classic example of type II (cytotoxic)hypersensitivity is trAnswerfusion reaction caused by mismatched blood.Type IV hypersensitivity reactions include infectious contact dermatitis,trAnswerplant rejection,and graft-versus-host disease.

Question 3

How should a patient be positioned in the initial management of an allergic reaction?&#10;A) seated upright in a chair&#10;B) standing&#10;C) prone&#10;D) supine

Accepted Answer

The patient should be placed in a head-down or supine position.The rescuer should make certain the airway is patent and administer oxygen.He or she should be prepared to send for help and to support respiration and circulation.

Question 4

Which of the following medications can be used as a dental local anesthetic if the patient reports previous allergic reaction to an amide local anesthetic?&#10;A) diphenhydramine (Benadryl)&#10;B) a selective COX-2 inhibitor&#10;C) codeine&#10;D) triamcinolone acetonide (Kenalog) in Orabase

Accepted Answer

Diphenhydramine can be used in the patient who reports a previous allergic reaction to both ester and amide local anesthetics.A 1% solution of diphenhydramine that contains 1:100,000 epinephrine can be compounded by a pharmacist,but it must be confirmed that methylparaben is not used as a preservative.This solution induces anesthesia of about 30 minutes average duration and can be used for infiltration or block injection.

Question 5

Most patients with asthma who react to NSAIDs also have ______.&#10;1.nasal polyps&#10;2.type II diabetes&#10;3.orthostatic hypotension&#10;4.gout&#10;A) 1, 3&#10;B) 2, 4&#10;C) 1&#10;D) 2

Accepted Answer

Most patients with asthma who react to NSAIDs also have nasal polyps and lack IgE- mediated allergy to airborne allergens.The mechanism for this reaction does not appear to be allergic but remains undefined.The dentist should be aware of the many multiple-entity analgesic preparations that include aspirin or other salicylates.These agents must not be given to the patient who may be endangered by an adverse reaction associated with aspirin or other salicylates.

Question 6

Which of the following types of hypersensitivity reactions involves the cellular immune system?&#10;A) type I&#10;B) type II&#10;C) type III&#10;D) type IV

Accepted Answer

Type IV hypersensitivity reactions involve the cellular immune system.Types I,II,and III hypersensitivity reactions involve elements of the humoral immune system.Allergic reactions that involve the cellular immune system often have delayed onset.Examples include contact dermatitis,graft rejection,graft-versus-host disease,some drug reactions,and some types of autoimmune disease.

Question 7

Foreign substances that trigger hypersensitivity reactions are called ________.&#10;A) antigens&#10;B) pathogens&#10;C) pyrogens&#10;D) toxoids

Accepted Answer

Allergic diseases result from an immunologic reaction to noninfectious foreign substances,called antigens.Under some circumstances,repeated contact with or exposure to an antigen may cause an inappropriate response (hypersensitivity)that can be harmful or destructive to host tissues; thus,hypersensitivity reactions can involve cellular or humoral components of the immune system.

Question 8

Which of the following groups of patients is most susceptible to allergic reactions caused by sulfites?&#10;A) renal dialysis patients&#10;B) people with emphysema&#10;C) asthmatics&#10;D) patients with chronic obstructive pulmonary disease

Accepted Answer

The group most susceptible to allergic reactions caused by sulfites includes the 9 to 11 million people in the United States in whom asthma has been diagnosed.Sulfites (sodium metabisulfite or acetone sodium bisulfite)used in local anesthetic solutions to prevent oxidation of the vasoconstrictors can cause serious allergic reactions.

Question 9

Which of the following immunoglobulins is involved in the pathogenesis of type I hypersensitivity reactions?&#10;A) IgA&#10;B) IgD&#10;C) IgE&#10;D) IgG&#10;E) IgM

Accepted Answer

Immunoglobulin E is the key antibody involved in the pathogenesis of type I hypersensitivity reactions.This reaction leads to the release of chemical mediators from mast cells and basophils in various target tissues.

Question 10

Contact stomatitis is considered to be type __ hypersensitivity.&#10;A) I&#10;B) II&#10;C) III&#10;D) IV

Accepted Answer

Contact stomatitis is a delayed allergic reaction that is associated with the cellular immune response in most cases.Because of the delayed nature of the reaction after contact is made with the allergen,the dentist must inquire about contacts with materials that may have occurred days before the lesions appeared.In many cases,no further treatment is necessary once the antigen has been identified and removed from further contact with the patient; however,if the tissue reaction is severe or persistent,topical corticosteroids should be used.

Deck 19: Allergy