Pilot study to determine the concordance between skin prick and intradermal test (IDT) reactivity to environmental allergens in atopic dogs using IDT as the gold standard.

BACKGROUND: Prick testing is widely used as the first-line in vivo test for environmental allergens in people owing to its noninvasive nature and speed of performance. OBJECTIVES: To determine concordance between skin prick testing (SPT) and intradermal testing (IDT) reactivity to environmental allergen mixes in dogs with atopic dermatitis (cAD). ANIMALS: Forty client-owned dogs with cAD. MATERIALS AND METHODS: Skin prick testing (GREER Pick System; Stallergenes Greer) and IDT were performed on 40 dogs using seven glycerinated and aqueous environmental allergen mixes, respectively (tree, grass and weed pollens, house dust mites and three mould mixes). Reactions for IDT and SPT were evaluated both subjectively and objectively (mean wheal diameter; MWD) and compared to saline and histamine controls. RESULTS: Using IDT as the gold standard, with subjective scoring, SPT was 47.0% sensitive [95% confidence interval (CI) 36.0%-58.7%], 92.1% specific (95% CI 87.6%-95.3%) and agreement was moderate (79%, Cohen's kappa = 0.424). The positive predictive value of SPT was 36% and negative predictive value was 95%. Objective and subjective scores had only fair agreement. CONCLUSIONS AND CLINICAL RELEVANCE: Skin prick testing with allergen mixes was specific yet poorly sensitive as compared to IDT. For both IDT and SPT, 95% (38 of 40) dogs failed to react to an allergen mix, despite showing a positive reaction to at least one component. Future studies comparing SPT and IDT should test individual allergens rather than mixes to prevent the dilution of individual components, which may have resulted in false negatives.

Alfaxalone provides reliable sedation for intradermal allergen testing in dogs and does not significantly affect results when compared to dexmedetomidine.

BACKGROUND: Dexmedetomidine (Dexmedetomidine hydrochloride-Dexdomitor; Zoetis) is the preferred sedative used for canine intradermal allergen testing (IDT) in the United States. Alfaxalone (Alfaxan Multidose; Jurox Animal Health) is a neuroactive steroid, and its effect on sedation and allergen reactivity scores is unknown. HYPOTHESIS/OBJECTIVES: We hypothesised that alfaxalone would produce an adequate level of sedation with fewer cardiovascular adverse effects and would not affect allergen reactivity scores or histamine wheal size compared to dexmedetomidine. MATERIALS AND METHODS: Twenty client-owned dogs were included in two groups: 10 atopic and 10 nonatopic. In a randomised, controlled, blinded, cross-over design all dogs underwent two modified IDT, 1-4 weeks apart, using intravenous dexmedetomidine (2.87-5.22 µg/kg) or alfaxalone (1.8-2.4 mg/kg). Anaesthetic parameters and sedation level were recorded over 25 min using a validated canine sedation scale described by Grint et al. (Small Anim Pract, 2009, 50, 62). Simultaneously, both objective and subjective reactivity scores were measured in technical triplicates at 10, 15 and 20 min. The modified IDT included eight allergens, histamine-positive and saline-negative controls. RESULTS: Alfaxalone produced a significantly higher sedation score across all time points (p < 0.05). All objective scores were significantly correlated to the corresponding subjective scores (Spearman R = 0.859, p < 0.0001). Sedative used did not significantly affect subjective allergen scores for nine atopic dogs (p > 0.05, 15 min). Sedative used did not affect the diameter of objective scores for individual allergens and histamine wheals (p > 0.05, 15 min). CONCLUSIONS AND CLINICAL RELEVANCE: Intravascular alfaxalone is an alternative sedative for IDT in dogs. Alfaxalone may be preferred to dexmedetomidine in some clinical scenarios as a result of having fewer cardiovascular adverse effects.

Effect of the topical administration of corticosteroids and tuberculin pre-sensitisation on the diagnosis of tuberculosis in goats.

BACKGROUND: Caprine tuberculosis (TB) is a zoonosis caused by members of the Mycobacterium tuberculosis complex (MTBC). Caprine TB control and eradication programmes have traditionally been based on intradermal tuberculin tests and slaughterhouse surveillance. However, this strategy has limitations in terms of sensitivity and specificity. Different factors may affect the performance of the TB diagnostic tests used in goats and, subsequently, the detection of TB-infected animals. In the present study, the effect of two of the factors that may affect the performance of the techniques used to diagnose TB in goats, the topical administration of corticosteroids and a recent pre-sensitisation with tuberculin, was analysed. METHODS: The animals (n = 151) were distributed into three groups: (1) a group topically treated with corticosteroids 48 h after intradermal tuberculin tests (n = 53); (2) a group pre-sensitised with bovine and avian purified protein derivatives (PPDs) 3 days before the intradermal tuberculin test used for TB diagnosis (n = 48); and (3) a control group (n = 50). All the animals were tested using single and comparative intradermal tuberculin (SIT and CIT, respectively) tests, an interferon-gamma release assay (IGRA) and a P22 ELISA. RESULTS: The number of SIT test reactors was significantly lower in the group treated with corticosteroids when compared to the pre-sensitised (p < 0.001) and control (p = 0.036) groups. In contrast, pre-sensitisation with bovine and avian PPDs did not cause a significant reduction in the number of SIT and CIT test reactors compared with the control group. In fact, a higher number of reactors was observed after the prior tuberculin injection in the pre-sensitised group (p > 0.05). No significant effect was observed on IGRA and P22 ELISA due to corticosteroids administration. Nevertheless, a previous PPD injection affected the IGRA performance in some groups. CONCLUSIONS: The application of topical corticosteroid 24 h before reading the SIT and CIT tests can reduce the increase in skin fold thickness and subsequently significantly decrease the number of positive reactors. Corticosteroids used can be detected in hair samples. A previous pre-sensitisation with bovine and avian PPDs does not lead to a significant reduction in the number of intradermal tests reactors. These results are valuable in order to improve diagnosis of caprine TB and detect fraudulent activities in the context of eradication programs.

Skin tests in the work-up of cutaneous adverse drug reactions: A review and update.

Skin tests, including patch tests (PTs), prick tests, and intradermal tests (IDTs), are useful in identifying the culprits of cutaneous adverse drug reactions (CADRs), and determining safer, alternative drugs. PTs have a low sensitivity but are valuable in investigating maculopapular exanthema (MPE), as well as severe CADR, including toxic epidermal necrolysis (TEN), Stevens-Johnson syndrome (SJS), and in particular, acute generalized exanthematous pustulosis (AGEP), and drug reaction with eosinophilia and systemic symptoms (DRESS). To ensure their specificity, at least 10 control tests should be performed. Prick tests are mainly used in the evaluation of immediate-type hypersensitivity and can be performed with all drugs, except opiates. IDTs can be used to explore immediate and delayed-type hypersensitivity, if an injectable form of the drug exists. Except for SJS/TEN, IDTs should be performed by injecting 0.02 mL of the drug. We here provide a practical, up-to-date review on the use of these skin tests in the work-up of CADRs. Numerous negative controls for drug PTs, as well as criteria for the immediate and delayed positivity of prick tests and IDT, are included. It should be emphasized that a negative result never excludes the potential responsibility of a drug in a CADR.

Correlation between carcass condemnations in slaughterhouses and official notifications of cattle testing positive for tuberculosis.

The objective of this study was to analyze the correlation between condemnations in slaughterhouses situated in Minas Gerais State and notifications to the Brazilian Official Veterinary Service of cattle that were positive for intradermal tuberculin tests. Data were obtained from three slaughterhouses under different surveillance conditions and from the Brazilian Agriculture and Livestock Health Agency for 2011 to 2017. During this period, there was an increase in the number of condemnations of females aged over 36 months, despite the number of females testing with intradermal tests and being reported as positive decreasing. Therefore, there is a discrepancy between the analyzed variables. Since there is a belief that slaughter condemnations can be used as tools for epidemiological surveys in beef and dairy farms, it is advisable for there to be a greater integration of the Brazilian Health Inspection Services in slaughterhouses and Brazilian Agriculture and Livestock defense department. This will ensure safe animal products.

Intradermal Testing With Radiocontrast Media to Prevent Recurrent Adverse Reactions.

OBJECTIVE. Adverse drug reactions (ADRs) to radiocontrast media are a significant social and economic burden and are difficult to predict. Because some ADRs to radiocontrast media may be immunologically induced, a skin test with diluted 1:10 radiocontrast media has been used to predict ADRs. However, using this test in clinical practice is difficult because of its low sensitivity. SUBJECTS AND METHODS. This study enrolled 36 patients with a history of immediate ADR to radiocontrast media who visited the Allergy and Asthma Clinic of Severance Hospital from 2017 to 2018. Patients underwent intradermal testing (IDT) with five types of diluted (1:10) and undiluted radiocontrast media (iohexol, iobitridol, iopamidol, iopromide, and iodixanol). The IDT result was regarded as positive if at least one radiocontrast medium elicited a positive reaction. Positivity of IDT and sensitivity to the culprit radiocontrast medium were calculated and compared. For subsequent CT examinations with a radiocontrast medium, the contrast agent eliciting a negative skin reaction in IDT was selected, excluding the previous culprit radiocontrast medium. RESULTS. IDT positivity and sensitivity for the culprit radiocontrast medium at 1:10 dilution were 47.2% and 47.2%, respectively, whereas the positivity and sensitivity for the undiluted radiocontrast medium were 86.1% and 75.0%, respectively. The positivity and sensitivity were higher with frequent radiocontrast medium use or with severe reaction. Of 22 patients who underwent another CT examination with the contrast medium selected on the basis of IDT results, 21 (95.5%) did not experience an ADR. CONCLUSION. IDT to prevent ADR should be performed with undiluted radiocontrast medium. Selecting an alternative radiocontrast agent on the basis of IDT results can be clinically useful to prevent recurrent ADRs to radiocontrast media.

Results of Intradermal Skin Testing with Cefazolin according to a History of Hypersensitivity to Antibiotics.

BACKGROUND: The relationship between cephalosporin hypersensitivity and a history of ß-lactam hypersensitivity is unclear. We evaluated the usefulness of routine intradermal cefazolin skin testing and its relationship with the history of ß-lactam hypersensitivity. METHODS: The electronic medical records of patients who underwent intradermal cefazolin (0.3 mg/mL) skin testing without negative controls from January 2010 to January 2011 at Seoul National University Bundang Hospital were evaluated. The history of ß-lactam hypersensitivity of the patients was taken. Immediate adverse reactions after cefazolin injection were evaluated by searching the electronic medical records for key words and reviewing consultation documents of allergy specialists or dermatologists. The medical records of the patients were reviewed by an allergist. RESULTS: There were 13,153 cases of cefazolin skin testing over the 13-month study period. Among the 12,969 cases with negative skin test results, 8 had immediate hypersensitivity related to cefazolin (0.06%). The negative predictive value of cefazolin skin testing alone was 99.94%. The overall positivity rate of cefazolin skin tests was 1.4% (184/13,153). Of the cases with a history of allergy to ß-lactams, 15% (6/40) showed a positive cefazolin skin test result compared to only 1.36% (178/13,113) of cases with no such history (P < 0.001) including some false-positive tests. CONCLUSION: The results suggest that routine screening involving cefazolin skin testing without negative controls is not useful for all patients, but could be helpful for those with a history of ß-lactam hypersensitivity, although a large prospective study is needed to confirm this.

Incidence of cephalosporin-induced anaphylaxis and clinical efficacy of screening intradermal tests with cephalosporins: A large multicenter retrospective cohort study.

BACKGROUND: Few studies have investigated the incidence of anaphylaxis induced by individual or structurally similar cephalosporins. The aims of the study were to assess the incidence of cephalosporin-induced anaphylaxis and evaluate the clinical efficacy of screening skin tests. METHODS: In this retrospective cohort study, we obtained information on total cephalosporin use and cephalosporin-induced anaphylaxis in intravenous cephalosporin recipients in 12 general hospitals between 2013 and 2015. Cephalosporins were divided into 4 groups according to similar side-chain structures. The incidence of cephalosporin-induced anaphylaxis was assessed for each cephalosporin, cephalosporin generation, and side-chain group. To verify the efficacy of screening intradermal tests (IDT) with cephalosporin, the 12 hospitals were assigned to the intervention or control group depending on whether they performed screening IDT before the administration of cephalosporins. RESULTS: We identified 76 cases of cephalosporin-induced anaphylaxis with 1 123 345 exposures to intravenous cephalosporins (6.8 per 100 000 exposures), and the incidence of fatal anaphylaxis by cephalosporin was 0.1 cases per 100 000 exposures. The highest incidences of anaphylaxis occurred in the ceftizoxime (13.0 cases per 100 000 exposures) and side-chain group 1 (cefepime, cefotaxime, ceftizoxime, ceftriaxone, and cefuroxime; 9.3 per 100 000). There was no case of anaphylaxis induced by cefoxitin, cefmetazole, cefminox, and cefotiam. The clinical effectiveness of routine screening IDT was not significant (P = .06). CONCLUSIONS: The incidence of cephalosporin-induced anaphylaxis differed according to individual drugs and side-chain structure. Screening IDT showed no clinical efficacy at a population level.

Non-immediate-reading skin tests and prolonged challenges in non-immediate hypersensitivity to beta-lactams in children.

BACKGROUND: A minority of children reporting non-immediate reactions to beta-lactams (BLs) are allergic. Allergy workup usually includes late-reading (48-72 hours) skin tests (ST) and short (1-3 days) drug provocation tests (DPT), regardless of the chronology of the index reaction. The sensitivity of hyper-late-reading (≥6-7 days) ST and of prolonged DPT for the diagnosis of non-immediate hypersensitivity to BLs is yet to be determined. OBJECTIVES: To establish the diagnostic values of late-reading ST and hyper-late-reading ST and of prolonged DPT in children reporting non-immediate reactions to BLs. METHODS: Prospective assessment of children reporting non-immediate reactions to BLs with late- and additional hyper-late-reading intradermal (ID) and patch tests, and if negative, with prolonged DPT. RESULTS: Five hundred and fifty children reporting reactions to a single or several BLs (674 suspected BLs) were included. Non-immediate hypersensitivity to BLs was diagnosed in 63 children (11.5%), reporting 66 reactions (9.8%), based on responses in ST (n = 17, 25.8%: 5 to ID, 8 to patch tests, and 4 to both tests), DPT (n = 43, 65.2%), and clinical history (n = 6, 9.1%), including 3/9 children with severe cutaneous adverse reactions. Skin test positivity was observed after the 6-7th day in 14/17 children, and DPT positivity after a median time of 3 days. No severe reaction was observed after ST or during prolonged DPT. CONCLUSION: Additional hyper-late-reading of ST enhanced their positivity. However, their overall sensitivity remained weak, especially in non-severe cases. Prolonged DPT are safe and may improve the performance of DPT in the diagnosis of non-immediate hypersensitivity to BLs.

Standardization and Prevalence of the Booster Phenomenon: Evaluation Using a Two-Step Skin Test with 43 kDa Glycoprotein in Individuals from an Endemic Region of Paracoccidioidomycosis.

BACKGROUND: We estimated the occurrence rate of the booster phenomenon by using an intradermal test with 43 kDa glycoprotein in an endemic area of paracoccidioidomycosis in the central-west region of Brazil. METHODS: Individuals who had a negative result on a survey performed by using an intradermal test with 43 kDa glycoprotein in an endemic area of paracoccidioidomycosis underwent a second intradermal test after 10-15 days to determine the presence or absence of the booster phenomenon. Statistical analyses were performed using the Chi-square test, Chi-square for linear trend test, Student's t test, and binomial test; p < 0.05 was considered significant. RESULTS: For the first time, we reported the occurrence of the booster phenomenon to an intradermal reaction caused by 43 kDa glycoprotein at a rate of 5.8-8.4%, depending on the test's cutoff point. This suggests that a cutoff point should be considered for the booster phenomenon in intradermal tests with 43 kDa glycoprotein: a difference of 6-7 mm between readings according to the first and second tests, depending on the purpose of the evaluation. CONCLUSION: The results indicate that the prevalence of paracoccidioidal infection in endemic areas is underestimated, as the booster phenomenon has not been considered in epidemiological surveys for this infection.

Patients with breakthrough reactions to iodinated contrast media have low incidence of positive skin tests.

BACKGROUND: The term "breakthrough reactions" designates repeated hypersensitivity reactions to iodinated contrast media (ICM) despite premedication with glucocorticoids and antihistamines. We aimed to retrospectively evaluate the rate of positive skin test (STs) in our cohort of patients with previous breakthrough reactions to different ICMs. METHODS: A series of 35 patients, who experienced at least one breakthrough reaction to ICM and who underwent STs within 6 months from the reaction were studied, and results were compared to a control group of patients with a first hypersensitivity reaction occurred without premedication. Skin prick tests (SPT), intradermal tests (IDT) and patch tests (PT) at different dilutions, with a set of three to four ICM were performed. RESULTS: Of the 35 patients with prior breakthrough reactions, 57% had an immediate reaction (IR) and 43% had a non-immediate reaction (NIR). Patients who experienced the first hypersensitivity IR or NIR, later had one or more breakthrough IR or NIR, respectively. Overall, 29% (10/35) of patients with prior breakthrough reactions resulted positive to STs compared to 57% (16/28) of the control group (p < 0.05). No significant difference in allergy history, age, sex, other clinical / demographic features nor chronic use of ACE-inhibitor, beta-blockers or NSAIDs was observed. CONCLUSION: This preliminary finding suggests that patients with prior breakthrough reactions have significantly lower immunologically proven ICM reactions (positive STs) if compared to non-breakthrough patients. According to that, a considerable number of breakthrough reactions seems to be non-allergic hypersensitivity reactions or reactions which could be mostly prevented by a proper, well-timed skin testing. Larger prospective studies are needed to confirm these results, with a more careful analysis of patients' risk factors, a laboratory assessment that includes an in vitro allergy diagnostics, and hopefully a drug provocation test for selected cases.

Delayed Skin Testing for Systemic Medications: Helpful or Not?

Cutaneous adverse drug reactions collectively are delayed drug reactions such as morbilliform drug eruption and severe cutaneous adverse reactions (SCARs). Morbilliform drug eruption may wane over time, be the result of drug viral interactions, and be amenable to slow reintroduction or rechallenge, whereas SCARs are HLA class I restricted, T-cell-mediated reactions that demonstrate durable immunity and warrant lifelong avoidance. SCARs such as drug reaction with eosinophilia and systemic symptoms, Stevens-Johnson syndrome and toxic epidermal necrolysis, acute generalized exanthematous pustulosis, and generalized bullous fixed drug eruption often occur in the setting of multiple drugs dosed together. Collectively, they lead to significant morbidity, mortality, and drug safety concerns that could severely limit future treatment options. Currently, no single or combination of diagnostic tests for SCARs such as ex vivo or in vitro testing, in vivo (skin) testing, or other adjunctive tests such as HLA typing have 100% negative predictive value. In this "Controversies in Allergy Review" article, we review the current literature on delayed skin testing (patch and delayed prick/intradermal test) and critically assess the evidence base of its utility across different drugs and clinical phenotypes of delayed hypersensitivity reactions.

DRESS syndrome due to iodinated contrast media. A case report.

BACKGROUND: The most frequent non-immediate reactions described with iodinated contrast media (ICM) are mild to moderate, however, some cases of patients with severe non-immediate reactions, such as drug eruption with eosinophilia and systemic symptoms (DRESS) have been described. CASE PRESENTATION: An 84-year-old patient developed DRESS syndrome after administration of ICM ioversol. The patient fullfilled the RegiSCAR diagnostic criteria for DRESS (definite score = 6). He underwent intradermal skin testing (IDT) with the widest panel of ICM available at our center. IDT was positive with ioversol and iomeprol. A punch biopsy was performed on the positive IDT with the culprit drug (ioversol) and histopathology was compatible with a T-cell mediated mechanism. CONCLUSION: In this case, the IDT-positive biopsy was consistent with DRESS syndrome caused by T-lymphocyte activation, supporting the clinical diagnosis.

Comparison of Skin Prick Tests (SPT), Intradermal Tests (IDT) and In Vitro Tests in the Characterization of Insect Bite Hypersensitivity (IBH) in a Population of Lusitano Horses: Contribution for Future Implementation of SPT in IBH Diagnosis.

Thirty controls (C) and 30 IBH-affected (T) Lusitano horses were evaluated. T horses were included based on anamnesis and physical examination, supported by questionnaires. All horses were submitted to skin tests, Intrademal (IDT) and Skin Prick Tests (SPT), on the neck with 14 specific allergens, 13 recombinant proteins (r-proteins) from Culicoides nubeculosus (Cul n) and Culicoides obsoletus (Cul o) salivary glands and Culicoides nubeculosus Whole Body Extract (Cul n WBE). Addicionally, a cluster of six T and six C horses were also tested with Cul n 3 and Cul n 4 produced in insect cells and barley, as well as E. coli produced Cul o 3 and Cul o WBE. Allergen concentrations were 10 µg/mL for IDT and 100 µg/mL for SPT, and wheal diameters assessed at 20 min, 6 and 48 h. IDTs were considered positive when wheal diameter was ≥50% of the histamine wheal and SPT's ≥ 0.9 cm. In vitro tests, allergen-specific serum IgE and sulfidoleukotriene (sLT) release assay were also carried out. Results showed that Cul n WBE, Cul n 7, 8, 9, Cul o1P and Cul o 2P were the best performing allergens for SPTs (p ≤ 0.0001) for the 1st allergen panel and Cul o WBE, Cul n 3 Bar and Cul n 4 Bac (p ≤ 0.05) for the 2nd, presenting a higher discriminatory diagnostic potential than IDTs, at a concentration of 100 µg/mL, with readings assessed at 20 min. Regarding in vitro tests overall, the sLT release assay performed best.

[Reproducibilidad clínica de reacciones de hipersensibilidad a fármacos en pruebas de exposición controlada].

Objective: To assess the reproducibility of symptoms in drug challenge tests. Methods: The study included patients with positive cutaneous or challenge test throughout 2019. For each patient, clinical suspicion according to Karch-Lasagna algorithm was registered. Primary outcome was the reproducibility of symptoms in the provocation tests using a paired analysis of data with McNemar test. Results: Eighty-nine patients were included, 16 of them presented more than one positive test. Thirty were skin tests positive and 75 reacted to provocation tests. Eighty nine percent of patients who reacted in challenge test were probably or possibly reactors according to Karch-Lasagna scale. Symptoms of initial reaction did not differ from those triggered in challenge tests. Conclusions: Karch-Lasagna scale is useful in predicting the response to drug provocation tests. In most of the positive studies, results were suggested by clinical history and no differences were found between symptoms triggered in challenge test and that referred to in the previous reaction.

Objetivo: Evaluar la reproducibilidad de los síntomas en pruebas de exposición con fármacos. Métodos: Estudio retrospectivo, efectuado en pacientes con prueba cutánea o exposición positiva, atendidos en 2019. De cada paciente se registró la sospecha clínica según el algoritmo de Karch-Lasagna. El resultado principal fue la reproducibilidad de síntomas en las pruebas de exposición, mediante el análisis de datos emparejado con prueba de McNemar. Resultados: Se incluyeron 89 pacientes, y de estos 16 reportaron varias pruebas positivas. Se obtuvieron 30 pruebas cutáneas y 75 de exposición positivas. En el 89% de las pruebas de exposición positivas, las reacciones iniciales se clasificaron en probables o posibles, según la escala de Karch-Lasagna. Los síntomas reportados en la reacción inicial no difirieron de los de las pruebas de exposición. Conclusiones: La escala de Karch-Lasagna es un método útil para predecir la respuesta en las pruebas de exposición con fármacos. En la mayor parte de las pruebas positivas, los resultados fueron sugeridos por la historia clínica, sin diferencias entre la manifestación de síntomas en la prueba de exposición versus los referidos en la reacción inicial.

Skin Tests for the Exploration of Hypersensitivity Reactions Associated with Iodinated Contrast Media.

BACKGROUND: Iodinated contrast media (ICM) are responsible for multiple side effects, especially hypersensitivity reactions. These reactions can either be authentic allergies or non-allergic hypersensitivity reactions. Skin tests (prick and intradermal tests) are simple to perform and can be of great help, especially if the ICM needs to be re-used. The aim of the study was to assess the characteristics of the patients in whom skin tests were performed and the results of these tests. METHODS: This is a retrospective study from June 2014 to June 2019. All included patients had at least one episode of hypersensitivity reaction to ICM and underwent skin tests. RESULTS: We included 35 patients aged 18 to 85 years. The iopromide was the most implicated ICM. The reactions were mainly cutaneous (n=30) and immediate (n=27). The skin tests were negative, except for two patients. The re-use of ICM occurred in 11 patients: 9 with an ICM other than the one suspected and two patients with the same ICM. Among these patients, 5 did not have any premedication. Two of them had a second hypersensitivity reaction, the first with another ICM and the second with the same ICM. CONCLUSION: One of the main pillars of allergic exploration is ICM skin testing, not only to prevent a recurrence, but also to allow patients to benefit from ICM re-use, which are sometimes essential.