J ALLERGY CLIN IMMUNOL

FEBRUARY 2014

AB266 Abstracts

TUESDAY

916 Novel Protocol For Successful Aspirin Desensitization In aPatient With Laryngeal Angioedema To Aspirin

Dr. Nikki Garg, MD, Dr. Pratik Patel, MD, Dr. Sindhura Bandi, MD;

Rush University Medical Center, Chicago, IL.

RATIONALE: Most established aspirin desensitization protocols have

been studied in patients with aspirin exacerbated respiratory disease

(AERD). Induction of drug tolerance protocols for other types of reactions

to aspirin are less well studied. It is unclear whether these protocols are true

desensitizations or graded challenges. Many patients with IgE mediated

reactions to aspirin experience symptoms even after the protocols are

completed.

METHODS: A 71 year old patient presented with angina and a history of

aspirin-induced angioedema which occurred 40 years ago. He again

developed physician observed laryngeal angioedema at an outside hospital

after ingesting 162mg of aspirin during a standardized desensitization. His

symptoms resolved after receiving steroids and diphenhydramine. Upon

transfer to our hospital, cardiology requested that he take aspirin 325 mg

daily before placement of a cardiac stent to avoid surgical intervention. He

was pretreated with montelukast 10 mg and diphenhydramine 50 mg daily

during the protocol. On day 1 he received 15 mg, 30 mg, and 60 mg of

aspirin 3 hours apart. On day 2 he received 60 mg, 81 mg, and 120 mg of

aspirin 3 hours apart. On day 3 he received 120 mg, 240 mg, and 325 mg of

aspirin 3 hours apart.

RESULTS: He tolerated the protocol without issue and continues to

tolerate 325 mg aspirin daily one month after stent placement.

CONCLUSIONS: Aspirin desensitization for symptoms other than

AERD is poorly understood. This novel protocol could be considered in

patients with reactions other than AERD including more classical allergy

symptoms like laryngeal angioedema.

917 Allergy To Beta-Lactams In Patients Consulting AllergologyCenter Of The Antioquia University, Colombia

Dr. Elizabeth Lopez1, Dr. Kaddy Juliana Beltran1, Dr. Jorge Sanchez1,

Dr. Ricardo Cardona-Villa, MD2; 1Universidad de Antioquia, Colombia,2Universidad de Antioquia, Medellin, Colombia.

RATIONALE: To determine the immunological component of patients

who are test with suspected of adverse reaction to beta-lactams in clinical

allergology center of Antioquia University in the period between January

2008 and October 2013.

METHODS: Patient histories were obtained of electronic medical

records, and they were offered investigation for penicillin allergy with

specific IgE, skin prick tests, intradermal tests (IDT), patch test and drug

challenge tests. Patients with case histories of reactions to other b -lactams

were also subsequently challenged with the culprit drug.

RESULTS: 590 allergy tests were made, 33 (15.6%) specific IgE by

immunoCAP, 78 (36.9%) IDT, 13 (6.1%) patch test and 92 drug challenge

tests. We studied 125 patients, 71 (56.8%) were females. 73 patients had an

immediate reaction, and 52 a non-immediate reaction. The severity of the

reported reactions was low in most cases: cutaneous rash and/or

angioedema 95 (73.6%), anaphylaxis 10 (7.7%), lower respiratory

symptoms 2 (1.5%), nonspecific symptoms 8 (6.2%). The drug most

frequently involved was amoxicillin in 62 patients (49.6%), crystalline

penicillin G 17 (13.6%), benzathine penicillin 15 (12%), cephalexin 13

(10.4%), Analysis of clinical histories showed that patients with a well-

defined history of allergy and a history of anaphylaxis were more likely to

have a positive test compared to patients with vague histories.

CONCLUSIONS: The data suggest that case history is often insufficient

to discriminate between immediate reactors and non-immediate reactors.

A minority of patients presenting with a history of b-lactam allergy have

evidence of immune-mediated hypersensivity in this study.

918 Effect Of Penicillin Allergy On Outpatient AntibioticPrescriptions At VA Hospital

Mark Biagtan, MD1,2, Bryan Babler, BS Pharm RPh2, Sujani

Kakumanu, MD1,2, Sameer K. Mathur, MD, PhD, FAAAAI1,2;

1University of Wisconsin School of Medicine and Public Health, Madison,

WI, 2William S. Middleton Veterans Hospital, Madison, WI.

RATIONALE: There is often overreporting of penicillin allergy. We

sought to characterize the classes of antibiotics prescribed for penicillin-

allergic patients in the outpatient setting compared to the general popu-

lation, and their associated costs. We hypothesized that patients designated

as penicillin-allergic are more likely to receive more expensive broad-

spectrum antibiotics compared to non-penicillin-allergic patients.

METHODS: In an IRB-approved protocol (HS-2012-0685), the William

S. Middleton VA Hospital medical records database was accessed to

identify patients with a penicillin allergy reported in 2008 and their

subsequent outpatient antibiotic prescription history from 2009 through

2012 compared to the non-penicillin-allergic population. The percentage

of patients receiving each class of antibiotics was compared. VA antibiotic

prices were used for estimates of cost differences.

RESULTS: 102 penicillin-allergic patients were identified with 352

outpatient antibiotic orders. Compared to the non-penicillin-allergic

population (12,563 patients with 61,146 outpatient antibiotic orders), a

significantly greater proportion of penicillin-allergic patients were pre-

scribed clindamycin, macrolides, 3rd/4th generation cephalosporins, and

vancomycin, and a significantly smaller proportion were prescribed

penicillin class antibiotics. Penicillin-allergic patients had a 60% greater

average estimated antibiotic cost.

CONCLUSIONS: Penicillin-allergic patients are prescribed a different

pattern of antibiotics, which are also more expensive, compared to non-

penicillin-allergic patients. Thus, evaluation in the Allergy clinic of the

penicillin allergy may facilitate the use of more appropriate and cost-

effective penicillin-related antibiotics.

919 Value Of Clavulanic Acid In Basophil Activation Test ForEvaluating Immediate Reactions To The CombinationAmoxicillin-Clavulanic Acid

Dr. Cristobalina Mayorga, PhD1, Dr. Adriana Ariza, PhD2,

Dr. Inmaculada Do~na, MD, PhD3, Dr. Maria Angeles Zambonino3,

Dr. Maria Isabel Monta~nez, PhD1, Dr. Maria Salas, MD, PhD3,

Ms. Maria Dolores Ruiz3, Ms. Lidia Melendez, Lab. Tech.1, Mrs. Maria

D. Ca~namero3, Dr. Miguel Blanca, MD, PhD3, Dr. Maria J. Torres, MD,

PhD3; 1Research Laboratory for Allergic Diseases, Hospital Regional

Universitario de Malaga - IBIMA, M�alaga, Spain, 2Research Laboratory

for Allergic Diseases, Hospital Regional Universitario de Malaga - FIMA-

BIS-IBIMA, Malaga, Spain, 3Allergy Service, Carlos Haya Hospital,

M�alaga, Spain.RATIONALE: Amoxicillin (AX) is frequently administered combined to

other betalactam, the clavulanic acid (CLV). Although initially thought to

have a low immunogenic capacity, immediate allergic reactions to CLV

have been reported in a 30% of patients allergic to AX-CLV. Basophil

activation test (BAT) has shown promising results demonstrating specific

recognition of CLV determinants. The aim of this study was to assess the

value of BAT in the evaluation of immediate allergic reactions to clavulanic

acid.

METHODS: Patients with a strong clinical history of having suffered an

immediate reaction after AX-CLV administration were evaluated. The

allergological study followed the European Academy guidelines, included

skin test with penicillin G, AX, and CLV determinants and drug

provocation test when indicated. BAT were carried out using AX and

CLVat different concentrations (2.5, 1.25, 0.25 and 0.05 mg/ml).

RESULTS: Among 75 patients included, 64 were finally diagnosed as

allergic, 26 to AX and 38 to CLV. The sensitivity of BATwas 60% and the

specificity 81.8%. The inclusion of AX determinant produced a BAT

sensitivity of 54.1%whereas CLV determinant produced a BAT sensitivity

of 78.6% with a specificity of 91% and 82% respectively. In patients

diagnostic as allergic to AX the BAT sensitivity was 50% whereas in

patients allergic to CLV, BAT sensitivity was 65.8%.

CONCLUSIONS: The inclusion of clavulanic acid in the basophil

activation test increase its diagnostic capacity in patients with immediate

allergic reaction to the combination amoxicillin-clavulanic acid.