Cefazolin 15 Urticaria (-) (-) (+) ND 2 F 46 Cefazolin 60 Urticaria (+) (-) (-) ND 3 F 50 Cefazolin 10 Anaphylaxis (-) (-) (+) ND 4 F 80 Cefazolin UK Anaphylaxis (-) (+) (+) ND 5 F 48 Cefazolin 2 Urticaria (-) (-) (+) (-) Cefuroxime AX/cefuroxime/meropenem 6 F 53 Cefazolin 5 Urticaria (-) (-) (+) (-) Cefuroxime AX/cefuroxime 7 F 34 Cefazolin 1 Anaphylaxis (-) (-) (-) † (-) Cefuroxime AX/cefuroxime 8 F 78 Cefazolin 1 Urticaria (-) (-) (+) (-) Cefuroxime AX/cefuroxime 9 F 62 Cefazolin 15 Urticaria (-) (-) (+) ND 10 M 55 Cefazolin 5 Urticaria (-) (-) (+) (-) Cefuroxime 11 F 53 Cefazolin 5 Urticaria (-) (-) (+) (-) Cefuroxime AX/cefuroxime 12 F 43 Cefazolin 50 Anaphylaxis (-) (-) (+) (-) Cefuroxime AX/cefuroxime 13 M 35 Cefazolin 15 Urticaria (-) (-) (+) (-) Cefuroxime AX/meropenem 14 M 73 Cefazolin 15 Urticaria (-) (-) (-) † (-) Cefuroxime AX/meropenem 15 M 51 Cefazolin 5 Anaphylaxis (-) (-) (+) (-) Cefuroxime 16 F 30 Cefazolin UK Urticaria (-) (-) (+) (-) Cefuroxime AX/cefuroxime 17 F 70 Cefazolin 5 Anaphylaxis (-) (-) (+) (-) Cefuroxime 18 M 70 Cefazolin 1 Urticaria (-) (-) (+) (-) Cefuroxime/ceftriaxone AX/cefuroxime/ceftriaxone 19 M 30 Cephalexin 20 Urticaria (-) (-) (-) † (-) Cefuroxime Cefuroxime 20 M 69 Cefadroxil 22 Urticaria (-) (+) ND (-) Cefazolin 21 F 40 Cefadroxil 30 Urticaria (-) (-) (-) † (-) Cefazolin 22 F 42 Cefadroxil 45 Urticaria (-) (-) (-) † (-) Cefazolin 23 F 62 Cephalothin 15 Anaphylaxis (+) (+) (+) (-) Cefuroxime (+) Cefotaxime 24 F 37 Cefaclor 20 Anaphylaxis (-) (-) ND (+) Cefotaxime/ceftriaxone (-) Cefazolin 25 F 17 Cefaclor 120 Urticaria (-) (-) (-) † (-) Cefazolin/cefuroxime/ceftriaxone 26 F 16 Cefaclor 180 Urticaria (+) (+) (+)* (-) Cefuroxime 27 F 15 Cefaclor 30 Anaphylaxis (-) (-) (-) † (-) Cefazolin/Cefuroxime AX/meropenem 28 F 46 Cefaclor 30 Urticaria (+) (+) ND (-) Cefuroxime/ceftriaxone 29 M 57 Cefonicid UK Anaphylaxis (-) (-) (-) † (-) Cefazolin

quality of life questionnaire in yellow jacket allergic patients. J Allergy Clin Immunol. 2002;109:162-7. 3. Armisen M, Guspi R, Alfaya T, Cruz S, Fernández S, DomínguezNoche C, et al. Cross-sectional validation of a quality of life questionnaire in Spanish for patients allergic to hymenoptera venom. J Invest Allegol Clin Immunol. 2015;25(3):176-82. 4. Alfaya T, Vega A, Domínguez-Noche C, Ruiz B, Marqués L, Sánchez-Morillas L. Longitudinal validation of the Spanish Version of the Health-Related Quality of Life Questionnaire for Hymenoptera Venom Allergy (HRQLHA). J Invest Allergol Clin Immunol. 2015;25(6):426-30. 5. Sturm GJ, Varga EM, Roberts G, Mosbech H, Bilo MB, Akdis CA, et al. EAACI guidelines on allergen immunotherapy: Hymenoptera venom allergy. Allergy. 2018;73(4):744-64. 6. Biló MB, Bonifazi F. The natural history and epidemiology of insect venom allergy: clinical implications. Clin Exp Allergy. 2009;39:1467-76. 7. Tripolt P, Arzt-Gradwohl LA, Cerpes U, Laipold K, Binder B, Sturm GJ. Large local reactions and systemic reactions to insect stings: similarities and differences. PLoS One. 2020;15(4). e0231747. 8. Bilo MB, Pravettoni V, Bignardi D, Bonadonna P, Mauro M, Novembre E, et al. Hymenoptera venom allergy: management of children and adults in clinical practice. J Invest Allergol Clin Immunol. 2019;29(3):180-205. 9. Golden DB, Kelly D, Hamilton RG, Craig TJ. Venom immunotherapy reduces large local reactions to insect stings. J Allergy Clin Immunol. 2009;123:1386-90. 10. Severino MG, Cortellini G, Bonnadonna P, Francescato E, Panzini L, Macchia D, et al. Sublingual immunotherapy for large local reactions caused by honeybee sting: a double-blind placebo-controlled trial. J Allergy Clin Immunol. 2008;122:448.

Background: Being labeled as allergic to penicillin (unverified ß-lactam allergy) can result in patients receiving broader-spectrum antibiotics than necessary that may be more toxic, less effective, and/or more expensive than alternative options. Objective: We aimed to evaluate the real costs of evaluating ß-lactam allergy. Methods: We performed a prospective real-life observational study designed to evaluate all adult patients who consulted for suspected ß-lactam allergy over a 1-year period. Direct and indirect costs were systematically recorded. Direct health costs were calculated based on the number of visits and all additional and diagnostic tests performed, direct nonhealth costs based on the number of visits and the distance from their homes to the Allergy Department, and indirect costs based on absenteeism. Results: A total of 296 patients with suspected allergy to ß-lactams were evaluated in our outpatient clinic from June 1, 2017 to May 31, 2018. Total direct health care costs were €28 176.70, with a mean (SD) cost of €95.19 (37.20). Direct nonhealth costs reached €6551.73, that is, €22.13 (40.44) per patient. Indirect health costs reached €20 769.20, with a mean of €70.17 (127.40). In summary, the total cost was €55 497.63, that is, a cost per patient of €187.49 (148.14). Conclusions: When all possible costs are taken into account, the evaluation of ß-lactam allergy is not expensive and can reduce future expense arising from unnecessary use of more expensive and less effective antibiotics.

Youngwoo Choi Dong-Hyun Lee Ji-Ho Lee Yoo Seob Shin Seung-Hyun Kim Hae-Sim Park Department of Allergy and Clinical Immunology, Ajou University School of Medicine, Suwon, Korea Clinical Trial Center, Ajou University Medical Center, Suwon, Korea Correspondence: Hae-Sim Park, Department of Allergy and Clinical Immunology, Ajou University School of Medicine, 164 World cup-ro, Yeongtong-gu, Suwon, Korea (hspark@ajou.ac.kr).

European Network on Drug Allergy (ENDA) has proposed an algorithm for diagnosing immediate beta-lactam (BL) allergy. We evaluated its performance in real life. During 1994-2014, 1779 patients with suspected immediate reactions to BL were evaluated following ENDA's short diagnostic algorithm. Five hundred and nine patients (28.6%) were diagnosed of BL hypersensitivity. Of them, 457 (25.7%) were at first evaluation [403 by skin tests (ST), 12 by positive IgE and 42 by controlled provocation tests (CPT)]. At second evaluation (SE), 52 additional patients (10.2% of allergic patients) were diagnosed, [50 (2.8%) by ST and 2 (0.1%) by CPT]. Time between reaction and study was significantly longer in patients diagnosed at SE (median 5 vs 42 months; IQR 34 vs 170; P < 0.0001). Anaphylaxis was significantly associated with a diagnosis at SE. European Network on Drug Allergy/EAACI protocol was appropriate and safe when evaluating BL immediate reactions. Re-evaluation should be performed, particularly when anaphylaxis and long interval to diagnosis are present.

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We report a case of contact dermatitis due to propylene glycol sensitization caused by an ultrasound gel with subsequent reactions to cosmetic products. A 24-year-old woman was referred following recurring episodes of eczematous lesions that had first appeared 1 year previously during the last trimester of pregnancy. The woman had previously attended our outpatient clinic owing to seasonal allergic rhinitis. The lesions were eczematous pruritic papules with exudation located on the abdomen, which the patient linked to the gel employed during ultrasonography (Aquasonic®, Parker Laboratories Inc., Hellendoorn, The Netherlands). She had undergone serial ultrasound examinations during the final phase of her pregnancy because of Type II intrauterine growth restriction. After several examinations the eczematous lesions became persistent with a notable worsening following each occasion. The patient linked her lesions to the ultrasound gel, but this association was considered unlikely by her doctor because the gel was labeled as ‘hypoallergenic’. After delivery, the patient presented with eczematous lesions in the area of the abdomen and nipples. On this occasion, she linked them to the use of a stretch mark repair cream (Vital Robert® cream, Ferrer Grupo, Barcelona, Spain) and a lactation nipple care cream (Trofolastin® Nipple care, Novartis, Barcelona, Spain). Patch tests with standard series (True Test®, Mekos Laboratories ApS, Hillerød, Denmark), ultrasound gel, stretch mark repair cream and nipple care cream were performed. Readings were obtained after 48 h and 96 h. Tests were positive for nickel (++ +), cobalt (+), ultrasound gel (++) and both cosmetic creams (++) (Figure 1). Patch tests with a series of vehicles and preservatives, and with a different ultrasound gel (Kendall Meditec, Mirandola, Italy) were performed. These tests were positive for the other gel (++) and for 2% propylene glycol (++). Components of the ultrasound gel Aquasonic 100, supplied by the manufacturer, include: water, moisturizer, polymer, propyl-paraben, methyl-paraben and FDC color. Propylene glycol was not mentioned. The other two creams and the other ultrasound gel did include propylene glycol in the descriptions of composition supplied by the manufacturers. Photograph of response to patch tests showing positive results for the ultrasound gel (++) and both cosmetic creams (++). Reactions to ultrasound gels are rare1-4 and are usually caused by moisturizers or preservatives. These gels are frequently labeled as hypoallergenic, but their composition is often not provided in detail, as we found in our case. Propylene glycol is a diol alcohol that can easily penetrate the skin, and so is widely used by pharmaceutical companies as a thinner, bacteriostatic solvent or vehicle, mainly for unstable drugs or water-insoluble substances. It can also be used as a moisturizing cream or a preservative, and is often included in food and cosmetic products. Propylene glycol can cause allergic contact dermatitis and skin or mucosa irritation5, 6. Usually, a concentration of 1–10% in water is recommended to prevent irritation5, 6. In our patient the clinical presentation and the positive patch test with a 2% concentration of propylene glycol strongly suggest an allergic contact dermatitis. As the patient had no history of contact dermatitis due to cosmetics, sensitization could have developed during the repeated ultrasound examinations that she underwent during her pregnancy. Although ultrasonography gels are frequently labeled as hypoallergenic it should be emphasized that this does not mean that they cannot induce allergic reactions. E. Moreno*, E. Macías*, I. Dávila*, E. Laffond*, T. Asensio*, F. Muñoz*, F. Lorente*, * Department of Allergy, University Hospital of Salamanca, Salamanca, Spain