Allergy Testing Workshop Marie Gilbert, PA-C, DFAAPA. April 24-27, 2014 Westin Convention Center Pittsburgh, PA

Transcription

1 Allergy Testing Workshop Marie Gilbert, PA-C, DFAAPA April 24-27, 2014 Westin Convention Center Pittsburgh, PA

2 Allergy Testing Workshop Clear Instruction Live Demonstration Hands-On Practice Learn by doing Understand principles of allergy skin testing Practice intradermal skin testing simulated patient Practice injections Practice intradermal skin testing mannequin Practice multi-test Manage anaphylaxis

3 Introduction There are multiple methods and techniques available to successfully complete all the topics presented in this workshop. Some are based on patient request, available equipment or supervising physician s preference. The goal of this workshop is to correctly demonstrate the most common methods and give participants time for hands on training.

4 Learning Objectives Learning objectives Discuss allergic disease as it relates to ENT practice. Understand principles of allergy testing. Demonstrate and practice allergy testing techniques. Understand and respond to allergic reaction (anaphylaxis)

5 Background Impact of allergic disease on patient population. Overall cost of Allergic Disease in U.S. $4.3 Billion Affects 10-30% Adults, 40% children

6 Goal is to improve quality of life by controlling symptoms and reducing incidence of infection.

7 Mechanism of Allergic Reaction Allergens IgE production Mast Cells Chemical mediators Histamine Leukotrienes Prostaglandin D 2 Kinins Early-phase reaction symptoms Itching Sneezing Rhinorrhea Nasal congestion T- and B-cell interaction Cellular infiltration Eosinophils Neutrophils Monocytes Basophils Late-phase reaction symptoms Nasal congestion Nasal hypersensitivity Rhinorrhea Fineman S: Rhinitis. In: Lieberman PL, Blaiss MS, eds. Atlas of Allergic Diseases. Philadelphia, PA: Lippincott Williams & Wilkins; 2002:

8 Patient History Onset of symptoms, modifying factors and severity of symptoms are important in determining treatment. However, history alone is insufficient to diagnose specific allergen sensitivity. Allergy tests help quantify sensitivity and optimize management. Non Allergic Food Perennial/Seasonal Sneezing Rhinorrhea Congestion Conjunctivitis

9 Treatment Options 4 General Principles of Management Environmental control measures Prescribe appropriate medications Test for allergies Immunotherapy

10 Environmental Control Dust & Mold avoidance most common allergens. Dust covers for pillows & mattresses HEPA vacuum for carpeting (remove carpet) Stuffed animals, etc Check & change A/C filter regularly. Mold testing in home as needed. Keep pets out of bedroom.

11 Medication Treatment is symptomatic; nasal obstruction should be treated with topical nasal steroid spray sneezing and rhinorrhea should be treated with an oral antihistamines. reactive airway with rhinorrhea consider adding leukotrienes inhibitor, etc. Treatment choices; OTC Pharmacotherapy Prescription Pharmacotherapy Please note that treatment is NOT one-dimensional. In many cases multiple treatment modalities are necessary to achieved adequate symptom relief.

12 Indications for Intranasal Steroids Intranasal steroids are indicated for management of the nasal symptoms of seasonal and perennial allergic rhinitis (SAR and PAR) in adults and children 4 years of age and older. Intranasal steroids relieves the nasal congestion, rhinorrhea, sneezing, and nasal itching associated with seasonal and perennial allergic rhinitis To maintain clinical benefit, Intranasal steroids should be used on a daily basis for at least 5 to 14 days.

13 Indications for Antihistamines Antihistamines are indicated for management of the allergic symptoms symptoms of seasonal and perennial allergic rhinitis (SAR and PAR) in adults and children 2 years of age and older. Antihistamines relieves symptoms of urticaria, rhinorrhea, sneezing, and nasal itching associated with seasonal and perennial allergic rhinitis but have little effect on congestion.

14 OTC Pharmacotherapy Mast Cell Stabilizers Intranasal cromolyn sodium Oral Antihistamines Benadryl, Claritin, Allegra, Zyrtec Decongestants Oral decongestants Sudafed ( b/p) Intranasal decongestants AFRIN, Neosynephrine, etc. BAD!! Intranasal saline

15 Prescription Pharmacotherapy Antihistamines Intranasal (Patanase,Astelin, Dymista) Systemic (Clarinex, Xyzal) Decongestants Systemic (Sudafed combinations, etc) Corticosteroids Intranasal (Flonase, Nasonex, Rhinicort AQ, etc.) Systemic (prednisone, medrol dose pack) Anticholinergics Intranasal (Atrovent ipratropium bromide) Leukotrienes blockers (Singular)

16 Allergy Testing

17 History In 1963, Rinkle introduce skin testing by otolaryngic allergist. Using fivefold dilution, and starting with anticipated nonreacting concentration, Rinkle raised intradermal wheals with progressively higher antigen strength until he found the concentration that first cause a positive wheal - end point of titration. He postulated that it represented the strongest concentration of antigens at which immunotherapy could be safely begun. This concept of skin endpoint titration has remained benchmark of methodology of allergy testing by otolaryngologist since Rinkle introduced it. Allergists on the other hand, traditionally utilized prick testing as their major skin testing methodology. Since prick testing introduces much less antigen then single dilution intradermal testing, it is the safer of the two methodologies. However, the argument can be made that if prick testing alone is used, patients with low degrees insensitivity will be missed. It is this philosophical differences that separates the general allergist from otolaryngic allergist.

18 Allergy Skin Testing Skin testing, skin prick testing (SPT) and intradermal dilutional testing (IDT) are the most popular in vivo test to confirm allergic sensitivity. 1 Skin testing is fast (15-30 minutes), safe, sensitive and a minimally invasive procedure which can be cost effective when performed correctly, it is also reproducible. Skin testing has demonstrated good correlation with results of nasal challenge 2 and bronchial challenges 3. Results of skin test should always be used as an adjunct to the clinical history and physical examination when making the diagnosis of allergic disease 1. Peltier et al, Otolaryngology-Head & Neck Surgery 137; , Bousquet et al, Clin Allergy 17:529-36, Cockcroft et al, Am Rev Respir Dis 135:264-7., 1987

19 Allergy Testing Intradermal Dilutional testing (IDT) specific/sensitive Mercado 2011 Inject cc of medication to produce wheal

20 Injection Technique Intradermal injection angle, bevel up just underneath dermis to make a wheel. Intramuscular- 90 angle, penetrates epidermis, dermis, subcutaneous tissue and muscle. Subcutaneous- 45 angle, penetrates epidermis, dermis, and subcutaneous tissue.

21 Interpreting Results When testing with antigen concentrations that increase in strength 5 fold increments, and reading test results at minutes, a typical intradermal injection of cc should produce a wheal of 4-5 mm, followed by positive a positive wheal (7 mm or larger), followed by a larger positive wheal (9 mm or larger). This is a normal wheal progression that holds true in almost 80% of all tested patient s. Plateau Reaction occurs when the first positive wheal is followed by another positive wheal of the same size. If a confirming wheal is obtained, then the second positive wheal is endpoint. Flash Response occurs when a series of negative wheals is followed by a very large positive wheal. This is generally thought to be due to ingestion of a concomitant food and testing should be discontinued and resumed in 4-7 days. Flash response Flash response Normal response Plateau reaction Negative response ID Injection 5mm Negative Wheal 7mm Endpoint 9mm Confirmatory Wheal

22 Allergy Testing Modified quantitative testing (MQT) combines SPT and IDT. MQT is nearly as effective as formal IDT in determining endpoint Peltier et al, Otolaryngology-Head & Neck Surgery 137; , 2007

23 Injection Technique Use enough pressure to leave impression. Gentle rocking motion to ensure equal penetration of all test head points. Bleeding should NOT occur. Compare antigen sites to + & - controls Positive control >7mm wheal. Negative control <6mm wheal.

24 Interpreting Results

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27 Practice Stations Practice injections (intramuscular and subcutaneous)- on simulators. Practice intradermal injection on mannequin then simulated patient (each other). 90 angle 45 angle angle Wheal

28 Immunotherapy (Allergy Shots) Immunotherapy (IMT) is the most effective treatment against airborne allergens, such as, pollen, dust and mold. Once the patients allergies are known from the skin testing, a minuscule amount of each allergen is injected into the patients arm which triggers the production of antibodies that can actually block allergy symptoms. The dose is gradually increased each week until eventually the patient can be exposed to the allergen without symptoms occurring. This process can begin working within 4 to 6 months and needs to be continued for as long as 3 to 5 years.

29 Management of Anaphylaxis

30 Management of Anaphylaxis Preparation Patient education, prescribe Epi-Pen Kit and teach patient how to use. Train and prepare staff to recognize and respond to anaphylaxis. Prevention-Practice protocols, have patients wait 20 minutes after injections/testing to monitor for reaction. Treatment- time is critical, identify true anaphylaxis and begin treatment.

31 Types of Reactions Vasovagal pale skin, cold sweats, and slow pulse, and normal blood pressure. Delayed allergic reaction-some patients develop enlarged wheal up to 6 hours after testing. Intermediate allergic reaction Local reactions Large local reactions Generalized (systemic) reactions

32 Sample Treatment Protocol 1. Cease administration of testing. 2. Identify true reaction (asses vitals). 3. Notify supervising clinician (call for help). 4. Administer epinephrine immediately. 5. Ensure patent airway. a) Bronchodilators b) The mechanical airway (intubation, LMA, etc.) c) Diphenhedramine d) Solumedrol 6. Begin CPR as needed.

33 Crash Kit Ensure medical supplies are current and that staff is trained to use. Medication Albuterol Diphenhedramine Solumedrol Ammonia Inhalant Epi-Pen Kit Equipment Intubation BVM Oxygen BP Cuff Stethoscope

34 Testing Pearls Medications to avoid Histamine challenge Dermatographia Hair/Pigmentation Emla Cream

35 Medications to Avoid Antihistamines suppress the wheel response. Avoid for hours before tests. Newer antihistamines like loratadine and its metabolite, desloratadine, should be avoided for 7 days. Tricyclic antidepressants should be avoided for 3-4 days. Beta blockers should also be avoided not because they affect wheal response, but because and can interfere with anaphylaxis therapy. Anti-inflammatories - Aspirin, Motrin, Ibuprofen, Aleve, Advil, and Alkaseltzer) H2 blockers - Axid, Pepcid, Prevacid, Priolosec, Protonix, Zantac, Tagamet, Tums, Mylanta, and Rolaids). Antiemetics (Example- Compazine) Predisone (oral corticosteroids) should be discontinued one month prior to allergy testing. Herbal supplement can interfere with allergy skin wheal responses, Licorice, Green tea, Saw Palmetto, St. John s Wart, Feverfew, Milk Thistle, and Astragalus. If unable to avoid above medication, intradermal testing should be avoided because results will be equivocal and may reduce anaphylaxis therapy. Consider RAST.

36 Alternative When patients cannot avoid medications that interfere with wheal response or affect treatment of anaphylaxis, RAST can be employed to measure IgE response and determine treatment. Radio-allergosorbent Test (RAST) IgE

37 Histamine Challenge The positive control most often used is histamine (.004mg/ml). An intradermal wheal of 4mm is raised and measured after10-15 minutes. A positive response is represented by wheal enlargement to 7mm or more. There is no significance to a histamine challenge that grows more than 7mm. Failure to produce positive histamine wheal is indication NOT to test patient.

38 Dermatographia Dermatographic urticaria (also known as dermographism, dermatographism or "skin writing") is a rare skin disorder seen in 4 5% of the worlds population and is one of the least common types of urticaria,in which the skin becomes raised and inflamed when stroked, scratched, rubbed, and sometimes even slapped. It is most common in teenagers and young adults, ages The symptoms are thought to be caused by mast cells in the surface of the skin releasing histamines without the presence of antigens, due to the presence of a weak membrane surrounding the mast cells. The histamines released cause the skin to swell in the affected areas. This is a contraindication for skin testing. These patients require RAST.

39 Hair/Pigmentation Hairy Patients Skin Color

40 Consider using a topical anesthetic for children or nervous patients. Shots can be scary. EMLA Cream should be applied under an occlusive dressing for at least 1 hour prior to test. For arm or back, use plastic wrap. Topical Anesthesia

41 Principles of Management Sneezing Congestion Environmental control measures Prescribe appropriate medications Rhinorrhea Test for allergies Conjunctivitis Immunotherapy Pharyngitis

42 Station 1 Allergy Testing Anaphylaxis Station 3 Allergy Testing Anaphylaxis Station 2 Allergy Testing Anaphylaxis Station 4 Allergy Testing Anaphylaxis

43 Allergy Testing Workshop Evaluation Score cards will be used for admission to workshops and attendance. Credit will only be awarded for completed score cards. Name Date On scale of 1 through 5 with 5 being most likely Scale Were learning objectives met? 2. Was instruction free of commercial bias? 3. Was there adequate instruction before practice? 4. Was there adequate supervision during practice? 5. Were training aids useful/realistic in learning skill? 6. How likely are you to perform these skills in future 7. Did this training improve your skills? Comments:

44 Allergy Testing Workshop Score cards Rotate and complete each station. Go/No Go for internal use only. Completion of workshop is NOT contingent on pass/fail. Understand indications for allergy skin testing. Perform intradermal skin test mannequin. Perform intradermal skin test simulated patient. Correctly administer injections (subcutaneous, intramuscular, intradermal). Correctly manage anaphylaxis reaction. Task Go No Go Comments

45 Recommend Reading Quantitative Skin Testing for Allergy Marple / Mabry Publication Date: August 2006