Allergy

Allergic diseases are a spectrum of clinical disorders that result from immunologic reactions to a noninfectious foreign substance (antigen) in a sensitized host. Allergic reactions affect multiple organ systems by mobilizing cells and chemical mediators within the immune system. Allergic disorders are increasing in prevalence, and this contributes significantly to increasing health care costs. An overview of the significant principles of allergic disease, including the various types of reactions that may be encountered in the dental office, is presented.

Epidemiology

Allergy is an abnormal or hypersensitive response of the immune system to a substance introduced into the body. It is estimated that more than 25% of all Americans demonstrate an allergy to some substance, including 10% to 20% who have allergic rhinoconjunctivitis, 7% who have a diagnosed food allergy, 7% who have asthma, 4% who are allergic to insect stings, and 5% who are allergic to one or more drugs. Allergic reactions account for about 6% to 10% of all adverse drug reactions. Of these, 46% consist of erythema and rash, 23% urticaria, 10% fixed drug reactions, 5% erythema multiforme, and 1% anaphylaxis. About a 1% to 3% risk for an allergic reaction is associated with administration of any drug. Fatal drug reactions occur in about 0.01% of surgical inpatients and 0.1% of medical inpatients.

Drugs are the most common cause of urticarial reactions in adults, and food and infection are the most common causes of these reactions in children. Urticaria occurs in 15% to 20% of young adults. In approximately 70% of patients with chronic urticaria, an etiologic agent cannot be identified.

Anaphylaxis in dental practice is estimated to occur in 0.004 to 0.015 cases per dentist per year. One of the more common triggers is penicillin. About 10% of people who take penicillin develop an allergic reaction, and 0.04% to 0.2% of them experience anaphylaxis. Death occurs in about 1% to 10% of those persons who experience an anaphylactic reaction, and usually death occurs within 15 minutes after administration of the drug. Fifty percent of the time, the allergic reaction starts immediately after drug administration. About 70% of affected patients report that they have taken penicillin previously. The most common causes of anaphylactic death are penicillin, bee stings, and wasp stings ; people with an atopic history are more susceptible to anaphylactic death than are patients with no history of allergy. Significant causes of anaphylaxis in clinical practice are listed in Box 19.1 .

Box 19.1
Causes of Human Anaphylactic Reactions of Importance in Health Care

  • Causative Agents

    • Antibiotics

      • Penicillins, sulfonamides, vancomycin

      • Amphotericin B, cephalosporins, nitrofurantoin

      • Ciprofloxacin, tetracyclines, streptomycin, chloramphenicol

    • Miscellaneous Drugs and Therapeutic Agents

      • Neuromuscular blocking agents (succinylcholine, d-tubocurarine)

      • Antitoxins, progesterone, thiopental

      • Vaccines, protamine sulfate, mechlorethamine

      • Acetylsalicylic acid, NSAIDs, opiates

  • Diagnostic Agents

      • Sodium dehydrocholate, radiographic contrast media

      • Sulfobromophthalein, benzylpenicilloyl polylysine (Pre-Pen)

  • Hormones

      • Insulin, parathormone, corticotropin

      • Synthetic ACTH

  • Enzymes

      • Streptokinase, penicillinase, chymotrypsin

      • Asparaginase, trypsin, chymopapain

  • Blood Products

      • Whole blood, plasma, gamma globulin

      • Cryoprecipitate, IgA

  • Latex

ACTH, Adrenocorticotropic hormone; IgA, immunoglobulin A; NSAID, nonsteroidal antiinflammatory drug.

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Sep 3, 2018 | Posted by in General Dentistry | Comments Off on Allergy
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