[Recurrence of drug eruption after renewed injection of iodinated contrast medium in patients with known allergic contraindications]. / Récidives de toxidermies après nouvelle injection de produit de contraste iodé chez des patients allergiques connus.

BACKGROUND: Iodinated contrast media (ICM) are used extensively by both radiologists and cardiologists. Injection of such products can induce immediate hypersensitivity reactions, some of which are IgE-mediated, and delayed hypersensitivity reaction with all types of drug eruptions being reported. Allergy tests, whether patch-tests or intradermal tests, are useful to confirm whether patients are allergic. At the end of these tests, depending on the reaction (chronology and clinical symptoms) and the results of the skin tests, patients are given an allergy card as well as a detailed certificate indicating the various ICM contraindicated and those allowed. OBSERVATIONS: We report herein three cases of patients experiencing a confirmed allergic eruption after injection of ICM, and whose recommendations and contraindication were not taken into consideration, leading to recurrence of eruption after renewed ICM injection. DISCUSSION: The three cases we report herein underscore the lack of knowledge concerning eruptions induced by ICM, particularly among radiologists. Better dissemination of information about the existence of such reactions appears necessary amongst the medical professionals concerned.

Immediate hypersensitivity to iodinated contrast media: diagnostic accuracy of skin tests and intravenous provocation test with low dose.

BACKGROUND: The diagnosis of HSR to iodinated contrast media (ICM) is challenging based on clinical history and skin tests. OBJECTIVE: This study evaluates the negative predictive value (NPV) of skin tests and intravenous provocation test (IPT) with low-dose ICM in patients with suspected immediate hypersensitivity reaction (HSR) to ICM. METHODS: Thirty-seven patients with suspected immediate hypersensitivity reaction to ICM were included retrospectively. Skin tests and a single-blind placebo-controlled intravenous provocation test (IPT) with low-dose iodinated contrast media (ICM) were performed. RESULTS: Skin tests with ICM were positive in five cases (one skin prick test and five intradermal test). Thirty-six patients were challenged successfully by IPT, and only one patient had a positive challenge result, with a grade I reaction by the Ring and Messmer classification. Ten of 23 patients followed up by telephone were re-exposed to a negative tested ICM during radiologic examination; two experienced a grade I immediate reaction. CONCLUSIONS & CLINICAL RELEVANCE: For immediate hypersensitivity reaction to ICM, the NPV for skin tests and IPT with low dose was 80% (95% CI 44-97%).

[A study of 19 cases of allergy to heparins with positive skin testing]. / Étude de 19 cas d'allergie aux héparines prouvée par des tests cutanés.

BACKGROUND: Allergic hypersensitivity to unfractioned or low-molecular-weight heparins is uncommon but is known, and in particular the most common form is localized dermatitis, although such cases have seldom turned into maculopapular exanthema. Since cross-reactions with other heparins are frequent, identification of therapeutic alternatives is essential. PATIENTS AND METHODS: This retrospective study included patients referred to the Department of Dermatology and Allergology at Tenon Hospital between 2000 and 2012 with suspicion of allergy to unfractionated heparin (UFH) or low-molecular-weight heparin (LMWH) and sensitized to at least one heparin (i.e. positive skin tests to at least one heparin). The heparins and hirudins used were tested in the forearm by means of intradermal skin tests. All patients were contacted in 2012 to establish whether they had used some form of heparin since the cutaneous allergy tests. RESULTS: Nineteen patients had at least one positive skin test for heparin; 1 patient had presented anaphylactic shock, while 18 others had presented localized eczema (12) or generalized dermatitis (6). The heparin most often responsible for these adverse reactions was enoxaparin (13/19). An LMWH was responsible in most cases (18 vs. 1 with UFH). Of these 18 patients, 16 also presented positive skin tests for UFH, 9 for synthetic heparinoid and 1 for hirudin. 11/19 patients were tested for fondaparinux (a synthetic pentasaccharid) and all had negative skin tests. 5/7 patients with negative skin tests had taken fondaparinux without any visible reaction, whereas 2 who also tested negative experienced localized eruption at the injection site. DISCUSSION: Our results underline the greater frequency of delayed hypersensitivity reactions compared with immediate reactions to heparins. Skin tests can help to identify substitution molecules. Fondaparinux might be an alternative but certain diagnosis relies on rechallenge.

Comparison of two basophil activation markers CD63 and CD203c in the diagnosis of amoxicillin allergy.

BACKGROUND: To confirm allergy to beta-lactam (BL), a basophil activation test in flow cytometry based on CD63 up-regulation was described. CD203c is a more recent basophil activation marker and up to day there is no consensus about which marker is the more sensitive one. CD203c has not yet been evaluated in the diagnosis of BL allergy. OBJECTIVE: The aim of the study was to compare the reliability of CD203c to CD63 for the diagnosis of amoxicillin (AX) allergy, which is nowadays the most frequent BL allergy. METHODS: Twenty-seven patients with an immediate positive skin test (ST) to AX, 20 had had anaphylaxis with AX and 7 had urticaria and/or angioedema, were compared with 14 controls with no allergy to BL and to six patients with delayed positive ST to AX. RESULTS: In the anaphylaxis group, AX induced up-regulation of CD203c in the basophils of 12 patients out of 20 (60%) and of CD63 in four patients (20%) (P<0.02). Two patients out of seven with urticaria or angioedema had a positive result with CD203c and CD63. In patients who had anaphylaxis, ampicillin (AMP) induced CD203c up-regulation in eight out of 12 (67%) patients tested, and CD63 up-regulation in 4 out of 12 (33%) (all patients who had anaphylaxis could not be tested with AMP). False-positive results were observed with CD203c as well as CD63, and for 10 patients indeed this was confirmed by a negative drug provocation test. The origin of conflicting results between CD63 and CD203c might be at least the targeting of basophils based on anti-IgE labelling. Among IgE(+) gated cells, by means of CD33, a marker of monocytes, a contamination up to 50% by monocytes was detected. In contrast to CD63, CD203c is an activation marker specific of basophils with a basal low-level expression in resting basophils. Thus, IgE and CD203c double targeting of basophils avoids the contamination by monocytes. CONCLUSION: CD203c seems to be a more sensitive activation marker of basophils than CD63 for the diagnosis of amoxicillin allergy.

[Anaphylactic reactions to aprotinin: intradermal diagnostic tests] . / Réaction anaphylactique à l'aprotinine: intérêt diagnostique des tests intradermiques.

A 66-year-old patient, undergoing heart surgery, developed an anaphylactic reaction following the first administration of a test-dose of aprotinin. Skin tests were performed six months later. Prick-tests with 10(-2) and 10(-1) aprotinin dilutions were negative but intradermal reaction with a 10(-3) dilution was clearly positive. The level of aprotinin specific IgE was high, both in the serum obtained before surgery and in the one sampled on the day of the testing. As no reaction was observed during the tests, skin-testing and specific IgE appear to be an interesting alternative to a potentially dangerous test-dose, but they both need further evaluation.

Latex allergy diagnosis: in vivo and in vitro standardization of a natural rubber latex extract.

For the diagnosis of IgE-mediated (immediate) hypersensitivity to natural rubber latex (NRL), skin prick testing with extracts of latex gloves has been widely used, but such extracts are difficult to standardize. The present study aimed to produce on an industrial scale an NRL extract from freshly collected NRL and to evaluate, calibrate, and standardize the extract by both in vivo and in vitro testing. The source material, latex of the rubber tree, Hevea brasiliensis (clone RRIM 600), was frozen immediately after collection in Malaysia and shipped in dry ice to Stallergènes SA, France. Protein and allergen profiles were analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), immunoblotting, isoelectric focusing (IEF), crossed immunoelectrophoresis (CIE), and crossed radioimmunoelectrophoresis (CRIE). Allergen quantification was effected by RAST inhibition. The capacity of the preparation to elicit immediate hypersensitivity reactions in vivo was measured by skin prick testing in 46 latex-allergic patients and 76 nonallergic control subjects. SDS-PAGE and immunoblot profiles of the extract and an NRL standard (E8) provided by the US Food and Drug Administration were almost identical, disclosing several distinct IgE-binding proteins with apparent molecular weights of 14, 20, 27, 30, and 45 kDa, conforming to reported molecular weights of several significant NRL allergens. An arbitrary index of reactivity (IR) of 100 was assigned to the extract at 1:200 dilution (w/v), having a protein content of 22 micrograms/ml. Skin prick testing of latex-allergic patients and controls using the extract at 100 IR revealed 93% sensitivity, 100% specificity, 100% negative predictive value, and 96% positive predictive value. In conclusion, a skin prick test reagent for diagnosis of type I NRL allergy was successfully standardized. The reagent was demonstrated to contain most, if not all, of the currently known clinically significant NRL allergens, and it showed high sensitivity and specificity.

The allergenic properties of fresh and preserved Hevea brasiliensis latex protein preparations.

The allergenic properties of the proteins of two lyophilized fractions of fresh natural rubber latex obtained by ultracentrifugation, the C serum and the sedimented bottom or lutoid fraction, have been compared with those of the serum proteins of two samples of high ammonia latex (HAL) [A]HALS obtained from HAL stored for more than 1 year, and [M]HALS derived from HAL stored for 6 weeks before ultracentrifugation and lyophilization. The most potent source of allergenic polypeptides both for skin prick testing of latex-sensitive patients and for immunoblots of their blood serum was the lutoid fraction of fresh latex. Skin prick tests and immunoblots of patients' sera showed that the allergenicity of the ammoniated latex decreased during storage. Skin prick tests using fractions of [A]HALS, C serum and lutoid proteins obtained after passage through a Sephacryl S300 column showed that the components of all three preparations which eluted in the largest volumes were almost equally effective in provoking the largest number of responses. Immunoblots of the sera of 43 latex-sensitive individuals showed that the majority (66%) of sera of the adult allergic patients reacted with a polypeptide of 19 kD. No characteristic pattern of binding latex polypeptides could be recognized in the sera from patients who were also asthmatic or from those who had an anaphylactic response to latex proteins.

Hypersensitivity to azathioprine mimicking gastroenteritis. Absence of recurrence with 6-mercaptopurine.

Hypersensitivity mimicking gastroenteritis is a rare complication of azathioprine therapy for which the mechanism is unknown. We report a case of devastating diarrhoea and vomiting due to azathioprine treatment in which hypersensitivity to the imidazole moiety of azathioprine was demonstrated. This has important therapeutic implications: in this situation, 6-mercaptopurine, which is the portion of azathioprine responsible for the cytotoxic therapeutic effect, can be administered without recurrence of side-effects.