UNIT 14 Allergy: An Overview

Key Terms Allergen Allergy Anaphylaxis Atopy Colic Desensitize IgE Reagin

Allergies Affect approximately 50 million people in the United States Number one cause of missed work and school Hay fever is most common chronic illness in United States (continues)

Allergies $500 million per year spent on OTC and prescription allergy treatment Hay fever Asthma Eczema/Dermatitis/Urticaria Conjunctivitis Food allergies

Latex Allergies Question each patient about latex allergy All allergies should be noted in red on patient chart Nonlatex gloves available for health care workers with latex allergies

Symptoms Dark circles under eyes Sneezing Wheezing/cough Redness of eyes or nose Nausea/vomiting Diarrhea Skin rash (continues)

Symptoms Headache Fatigue In children Colic Restlessness Irritability Disruptive behavior Other symptoms similar to adults

Factors That Trigger Symptoms Allergens Fatigue Stress Overexertion Weather changes Seasonal allergies Early spring: trees Late spring and summer: grasses Fall: weeds

Diagnostic Tests Nasal smears Sinus x-rays Laboratory tests Skin tests Patch Scratch Intradermal

Scheduling Allergy Tests Must discontinue all allergy mediations, both OTC and prescription, 7 days before testing Must discontinue all corticosteroids 30 days before testing Warning! When performing allergy testing, always be sure to have epinephrine and an antihistamine such as diphenhydramine on hand in case of anaphylaxis. Allergy testing may only be done when a physician is present.

Scratch Tests Allergen placed on skin Scratched with sterile lancet Allergens labeled Patient to lie still for 20 minutes Reaction indicated by degree of redness or size of wheal

Patch Tests Gauze soaked with suspected allergen and placed on skin Secured with nonallergenic tape Reactions read at 24-hour and 48-hour intervals Reaction determined by size of wheal (continues)

Patch Tests Discussion Questions: Why must patients lie still for 20 minutes during scratch testing? Why would a patch test be done instead of a scratch or intradermal test?

Intradermal Tests Allergen injected below skin Serial dilution end-point titration determines allergy and individual’s level of sensitivity

Laboratory Tests RAST PRIST Determines IgE serum level Uses highly specific antibody that binds only to IgE

Nasal Smears Infection Allergic rhinitis Bacteria or neutrophils Eosinophils Goblet cells or mast cells

Sinus X-Rays Taken when patient has chronic sinusitis Sinusitis indicated by Thickened mucosa Significant opacity Air fluid level

Treatment Avoid allergens Drug therapy Immunotherapy

Avoid Allergens Modes of entry Inhalation Ingestion Direct contact Injection Insect stings

Drug Therapy Antihistamines Decongestants Counter effects of histamine in body Available by prescription or OTC Decongestants Relieve nasal congestion Cause vasoconstriction (continues)

Drug Therapy Warning! Due to their effect of vasoconstriction, decongestants should be used with extreme caution in patients with hypertension, glaucoma, diabetes, or with prostatic hypertrophy. (continues)

Drug Therapy Antileukotrienes-leukotrienes receptor antagonists Fight inflammation in airway Bronchodilators Dilate bronchi to improve airflow Corticosteroids Anti-inflammatory agents (continues)

Drug Therapy Monoclonal antibody-omalizumab Blocks IgE Only effective for patients with persistent allergic asthma (continues)

Drug Therapy Cromolyn sodium Prevents and treats allergic rhinitis Inhibits degranulation of sensitized mast cells Inhibits release of histamine and SRS-A

Immunotherapy “Allergy shots” Desensitizes individual to allergen Treatment of choice when Allergy is IgE-mediated (continues)

Immunotherapy Patient unable to avoid allergen Inadequate response to other treatment Symptoms interfere with lifestyle Patient ready to accept and adhere to regimen

Administration Guidelines for Allergenic Extracts Always given sq, using TB syringe Extracts must be kept refrigerated Rotate sites Patient to remain in office 15–30 minutes after injection Observe for reactions

Stinging Insects Safety tips Move slowly, do not swat or slap Wear close-fitting clothes Use extreme caution after rainstorm Avoid flowery perfumes, lotions, etc. Scrape out stinger, do not squeeze (continues)

Stinging Insects Discussion Questions: Why should you not use tweezers to try to remove a stinger? Why are stings more likely after a rainstorm? (continues)

Stinging Insects Warning! Seek immediate medical attention for Swelling away from site of sting Nausea or vomiting Difficulty breathing Weakness or dizziness Hives