Tranexamic acid as maintenance treatment for non-histaminergic angioedema: analysis of efficacy and safety in 37 patients.

Angioedema (AE) is a clinical syndrome characterized by localised swelling lasting several hours. The swelling is often recurring and can be lethal if it is located in the laryngeal region. Much progress has been made recently in the treatment of acute episodes, but no consensus has been reached on maintenance treatment. We have performed a national retrospective observational study to assess the use of tranexamic acid (TA) as maintenance treatment for non-histaminergic AE [hereditary AE (HAE) or idiopathic non-histaminergic AE]. Records for 64 cases were collected from 1 October 2012 to 31 August 2013; 37 of these were included (12 HAE with C1-inhibitor deficiency, six with HAE with normal C1-inhibitor and 19 idiopathic non-histaminergic AE). When treated with TA over six months, the number of attacks was reduced by 75% in 17 patients, 10 patients showed a lower level of reduction and 10 had the same number of attacks. In no instances were symptoms increased. No thromboembolic events were observed, and the main side effects were digestive in nature. Thus, TA, which is well tolerated and inexpensive, appears to be an effective maintenance treatment for some patients with HAE or idiopathic non-histaminergic AE.

Benefits of progestin contraception in non-allergic angioedema.

BACKGROUND: Hereditary angioedema attacks can be induced or worsened by oral contraceptive containing oestrogens. OBJECTIVES: The purpose of this study was to assess the impact of progestin contraceptives on angioedema attacks. METHODS: We conducted a French retrospective, multi-centre study of progestin contraception in women with non-allergic angioedema, including hereditary angioedema type I, II and III and idiopathic angioedema. Patients were classified into four groups according to frequency of attacks. We evaluated the effects of progestin on the mean number of attacks and compared the number of patients in each group before and under progestin contraception. The influence of hormonal factors on the course of angioedema was also assessed. RESULTS: Fifty-five women were included: mean age was 32.1 years (16-52) and mean follow-up 32.4 months (SD:29). Fourteen women were classified as type I (25.4%), two as type II (3.6%) and 19 as type III (34%) and 20 were idiopathic (36%). Seventeen patients were taking a low dose progestin-only pill (POP), 24 antigonadotropic progestins (AGP) and 14 both successively. Total or partial improvement was observed in 81.8% (45/55) of the patients and more frequently in those on an AGP agent (34 patients, 89.5%) than on POP (19 patients, 61.3%) (P = 0.013). CONCLUSIONS & CLINICAL RELEVANCE: This is the first study evaluating the interest of antigonadotropic progestin contraception in a series of women with non-allergic angioedema. Progestins, especially antigonadotropic progestins, appear to convey a marked benefit in most cases. Antigonadotropic progestins could thus be recommended as adjuvant treatment in childbearing women with non-allergic angioedema.

Anaphylaxis to pork kidney is related to IgE antibodies specific for galactose-alpha-1,3-galactose.

BACKGROUND: Carbohydrate-specific IgE antibodies present on nonprimate mammalian proteins were incriminated recently in delayed meat anaphylaxis. The aim of this study was to explore whether anaphylaxis to mammalian kidney is also associated with galactose-α-1,3-galactose (αGal)-specific IgE. METHODS: Fourteen patients with anaphylaxis to pork or beef kidney underwent prick tests to meat and kidney. Some patients also underwent skin tests to Erbitux(®) (cetuximab). IgE antibodies to αGal, swine urine proteins, beef and pork meat, serum albumin proteins, cat, and rFel d 1 were measured by ImmunoCAP(®). The αGal levels were estimated in meats and kidney by ELISA inhibition assay. Cross-reactivity between αGal and pork kidney was studied with the ImmunoCAP(®) inhibition assay. RESULTS: Among the 14 patients, 12 presented with anaphylactic shock. Reactions occurred within 2 h from exposure in 67% of patients. Associated risk factors were observed in 10 cases, and alcohol was the main cofactor. Three patients underwent an oral challenge to pork kidney, and anaphylaxis occurred after ingestion of small quantities (1-2 g). Prick tests to kidney were positive in 54% of patients. All tested patients showed positive skin tests to Erbitux(®). All patients tested positive for IgE to αGal, with levels ranging from 0.4 to 294 kU/l. IgE binding to αGal was inhibited by raw pork kidney extract (mean, 77%; range, 55-87%), which showed a high amount of αGal determinants. CONCLUSIONS: Pork or beef kidney anaphylaxis is related to αGal IgE. Its peculiar severity could be due to an elevated content of αGal epitopes in kidney.

An apple a day ... chronic glossitis in a 4-year-old boy.

We report a case of chronic glossitis in a 4-year-old boy due to scurvy. The boy showed up in our department with a patchy depapillated tongue. A detailed dietary history revealed an unbalanced diet without any fruit or vegetable. The biological investigations showed a low serum ascorbic acid. The boy was treated by oral ascorbic acid during 15 days. The glossitis improved within one week and serum levels of vitamin C returned to the normal range. In industrial countries, scurvy became a rare disease in healthy children. However, since a few years, cases are reported in children and teenagers with unbalanced diet coming from economically favoured families. These extreme cases are one of the signs of a more general deterioration of dietary habits in paediatric populations in our societies. This emphasizes the importance of effective nutritional education programs aimed towards both parents and children.

A novel immunoassay using recombinant allergens simplifies peanut allergy diagnosis.

BACKGROUND: Double-blind placebo-controlled food challenge (DBPCFC) is currently considered the gold standard for peanut allergy diagnosis. However, this procedure that requires the hospitalization of patients, mostly children, in specialized centers for oral exposure to allergens may cause severe reactions requiring emergency measures. Thus, a simpler and safer diagnosis procedure is needed. The aim of this study was to evaluate the diagnostic performance of a new set of in vitro blood tests for peanut allergy. METHODS: The levels of IgE directed towards peanut extract and recombinant peanut allergens Ara h 1, Ara h 2, Ara h 3, Ara h 6, Ara h 7, and Ara h 8 were measured in 3 groups of patients enrolled at 2 independent centers: patients with proven peanut allergy (n=166); pollen-sensitized subjects without peanut allergy (n=61), and control subjects without allergic disease (n=10). RESULTS: Seventy-nine percent of the pollen-sensitized patients showed IgE binding to peanut, despite their tolerance to peanut. In contrast, combining the results of specific IgE to peanut extract and to recombinant Ara h 2 and Ara h 6 yielded a peanut allergy diagnosis with a 98% sensitivity and an 85% specificity at a positivity threshold of 0.10 kU/l. Use of a threshold of 0.23 kU/l for recombinant Ara h 2 increased specificity (96%) at the cost of sensitivity (93%). CONCLUSION: A simple blood test can be used to diagnose peanut allergy with a high level of precision. However, DBPCFC will remain useful for the few cases where immunological and clinical observations yield conflicting results.

Processing-dependent and -independent pathways for recognition of iodinated contrast media by specific human T cells.

BACKGROUND: One to three percent of patients exposed to intravenously injected iodinated contrast media (CM) develop delayed hypersensitivity reactions. Positive patch test reactions, immunohistological findings, and CM-specific proliferation of T cells in vitro suggest a pathogenetic role for T cells. We have previously demonstrated that CM-specific T cell clones (TCCs) show a broad range of cross-reactivity to different CM. However, the mechanism of specific CM recognition by T cell receptors (TCRs) has not been analysed so far. OBJECTIVE: To determine how T cells specifically recognize CM. METHODS: CM-specific TCCs were generated from human blood of three CM-allergic patients and a specific TCR was transfected into a mouse T cell hybridoma. Functional analysis such as proliferation assays, IL-2 secretion assays, and calcium influx experiments were performed using irradiated, glutaraldehyde-fixed, CM-pre-incubated, human leucocyte antigen (HLA)-DR-matched or -mismatched antigen-presenting cells (APCs), and HLA-blocking antibodies. RESULTS: We identified two mechanisms of T cell stimulation: some TCCs and the transfectant reacted to CM independent of uptake by APCs because proliferation/IL-2 secretion occurred in the presence of glutaraldehyde-fixed APCs, and intracellular calcium increased within seconds after drug addition. Other TCCs required functional APCs, compatible with uptake and presentation of CM on MHC-class II molecules, as implied by three findings: (1) glutaraldehyde fixation of APCs abrogated presentation; (2) CM could not be washed away from CM-pre-incubated APCs; and (3) the optimal pulsing time was 10-20 h. Because allogeneic, MHC-matched, CM-pulsed APCs could induce proliferative responses as well, the ability of CM uptake and presentation is not unique to APCs from patients with CM-induced delayed hypersensitivity. CONCLUSION: Our data suggest that CM may be stimulatory for T cells either by direct binding to the MHC-TCR complex or by binding after uptake and processing by APCs. This questions the assumed inert nature of CM.

Prospective study of sensitization and food allergy to flaxseed in 1317 subjects.

BACKGROUND: Foods containing flaxseed proteins rich inpolyunsaturatedfatty acids are new on the market. OBJECTIVES: In a population of patients attending the allergology department, we evaluated the frequency of sensitization to flaxseed, characterized allergens and looked for modifications related to industrial processing. METHODS: Natural, heated and extruded flaxseeds were tested using prick-in-prick tests (PIP using the fresh seed), SDS PAGE, immunoblots, immunoblot inhibition and Fourier Transform Infrared (FTIR) spectroscopy. RESULTS: PIP tests to natural flaxseed were positive in 5.8% of the 1317 patients. 73 of 77 PIP-positive patients were atopic. There was cross-reactivity with five seeds. peanut, soybean, rapeseed, lupine and wheat, and with rape pollen. Immunoblot inhibition by bromelain confirmed the presence of specific IgE to cross-reactive carbohydrate determinants (CCD). 0.15% of this population presented with food allergy to flaxseed and positive PIP to heated and extruded flaxseed. Two sera showed that clinically relevant allergens in industrial products had MW between 25 and 38 kDa. Sensitization to processed flaxseed characterized only the allergic subjects. FTIR spectroscopy showed major modifications in 3 and alpha structures following industrial processing. CONCLUSION: Positive prick tests to natural flaxseed were mainly due to cross-reactions. Flaxseed allergy is rare and could be detected by PIP to heated extruded flaxseed. Increasing consumption callsfor monitoring of clinical risk.

Skin testing in patients with hypersensitivity reactions to iodinated contrast media - a European multicenter study.

BACKGROUND: Iodinated contrast media cause both immediate and nonimmediate hypersensitivity reactions. The aim of this prospective study was to determine the specificity and sensitivity of skin tests in patients who have experienced such reactions. METHODS: Skin prick, intradermal and patch tests with a series of contrast media were conducted in 220 patients with either immediate or nonimmediate reaction. Positive skin tests were defined according to internationally accepted guidelines. Seventy-one never-exposed subjects and 11 subjects who had tolerated contrast medium exposure, served as negative controls. RESULTS: Skin test specificity was 96-100%. For tests conducted within the time period from 2 to 6 months after the reaction, up to 50% of immediate reactors and up to 47% of nonimmediate reactors were skin test positive. For immediate reactors, the intradermal tests were the most sensitive, whereas delayed intradermal tests in combination with patch tests were needed for optimal sensitivity in nonimmediate reactors. Contrast medium cross-reactivity was more common in the nonimmediate than in the immediate group. Interestingly, 49% of immediate and 52% of nonimmediate symptoms occurred in previously unexposed patients. Many of these patients were skin test positive, indicating that they were already sensitized at the time of first contrast medium exposure. CONCLUSIONS: These data suggest that at least 50% of hypersensitivity reactions to contrast media are caused by an immunological mechanism. Skin testing appears to be a useful tool for diagnosis of contrast medium allergy and may play an important role in selection of a safe product in previous reactors.

Nonsteroidal anti-inflammatory drug hypersensitivity syndrome. A multicenter study. I. Clinical findings and in vitro diagnosis.

BACKGROUND: We present the results obtained from the largest series of in vitro diagnostic tests ever reported in patients with clinically validated hypersensitivity to acetylsalicylic acid (ASA)/nonsteroidal anti-inflammatory drugs (NSAID) compared with various categories of controls tolerating ASA/NSAIDs. This multicenter study, which was performed within the framework of the European Network for Drug Allergy (ENDA) group, showed that the basophil activation test (BAT), particularly when used with the 3 NSAIDs aspirin (ASA), diclofenac (DIC), and naproxen (NAP), allows us to confirm the diagnosis of NSAID hypersensitivity syndrome. The results of the cellular allergen stimulation test (CAST) frequently correlate with those of the BAT, although not always. An unexpected finding was that basophil activation by NSAIDs is not an all-or-nothing phenomenon restricted to clinically hypersensitive patients, but that it also occurs in a dose-related manner in some NSAID-tolerant control individuals.Therefore, NSAID hypersensitivity appears as a shift in the normal pharmacological response to NSAIDs. These findings allow us to formulate a new rational hypothesis about the mechanism of NSAID hypersensitivity syndrome, a mechanism that most authors continue to describe as "unknown." METHODS: We enrolled 152 patients with a history of hypersensitivity to NSAIDs and 136 control participants in 11 different centers between spring 2003 and spring 2006. Flowcytometric BAT was performed. RESULTS: The most noteworthy results of our study were that 57% of 140 patients presented very clear-cut positive BAT results to multiple NSAIDs, and 16% were entirely negative. In about 27% of cases, positive results were obtained with 1 or 2 concentrations of a single NSAID. There is clearly a correlation between the results of BAT and CAST. CONCLUSIONS: BAT seems particularly indicated in patients with a clinical history of NSAID intolerance, and in whom a provocation test is not advisable for ethical, clinical, or other reasons. Clear-cut positive results can be considered as confirming a history of NSAID hypersensitivity, although negative results may not exclude it.

Pre-lethal anaphylaxis to carboxymethylcellulose confirmed by identification of specific IgE--review of the literature.

BACKGROUND: Carboxymethylcellulose (CMC) is used extensively in the pharmaceutical and food industries on account of its various properties. Anaphylactic reactions are rare. It has been reported principally after intra-articular infiltration of sustained-release corticosteroids containing CMC and, very rarely, after barium enema. METHODS: A case of pre-lethal anaphylactic shock after barium enema was studied by prick-test, intra-dermal reaction (IDR), leukocyte histamine release test (LHRT), basophil activation test (BAT), cystein-leukotriene release test (CAST) and dot-blot analysis. RESULTS: IDR to CMC was positive at a concentration of 10 microg/ml. BAT and CAST were positive. Specific IgE were identified using dot-blot analysis. DISCUSSION: This is the third report of CMC-specific IgE and the second of anaphylaxis to CMC associated with a barium suspension in contact with GI tract mucosa. CMC as an excipient in medicinal products may therefore be a risk factor for severe anaphylaxis after injection or following contact with GI tract mucosa. Sensitization and allergic reactions by CMC in food additives have to be considered.

A murine model of cow's milk protein-induced allergic reaction: use for safety assessment of hidden milk allergens.

BACKGROUND: Masked allergens in processed food products can lead to severe allergic reactions following unintentional ingestion. We sought to develop a murine model for the detection of hidden cow's milk proteins (CMP). This study aimed to induce cow's milk allergy in mice, to characterize the anaphylaxis induced by CMP in this model, and to validate its reliability using three margarines manufactured with (A) or without (B, C) milk, sharing the same production line. MATERIALS AND METHODS: Three-week-old BALB/c mice were sensitized intragastrically with CMP plus cholera toxin and boosted 6 times at weekly intervals. CMP-sensitization status was monitored by skin tests, and measurement of CMP-specific IgE and IgG1 levels. On day 44, the minimal threshold of clinical reactivity to CMP in terms of anaphylaxis was determined by performing a dose response of intraperitoneal CMP challenge. Under the same conditions, anaphylaxis was evaluated in CMP-sensitized mice after challenge with protein extracts of margarines A, B or C. RESULTS: Sensitization to CMP was demonstrated by positive skin tests and increased CMP-specific IgE and IgG1. The minimal clinical reactivity threshold corresponding to 0.1 mg CMP elicited detectable anaphylaxis evidenced by clinical symptoms, a decrease in breathing frequency, and increased plasma histamine upon challenge. Similarly, challenges with margarine A containing CMP demonstrated anaphylaxis, whereas those with B or C did not elicit any detectable allergic reaction. CONCLUSION: This study shows that our murine model of CMP-induced anaphylaxis is useful for investigating the allergenic activity and the assessment of margarines with respect to milk.

The economic costs of severe anaphylaxis in France: an inquiry carried out by the Allergy Vigilance Network.

BACKGROUND: The prevalence of severe anaphylaxis, between 1 and 3 per 10,000, has increased sharply over recent years, with a rate of lethality of 1%. The economic burden is unknown. OBJECTIVE: The aim of this study was to estimate the economic costs of anaphylaxis, including direct costs of treatment, hospitalization, preventive and long-care measures, and the indirect cost: absenteeism. METHODS: Analysis of 402 patients of anaphylaxis declared by 384 allergists was reported to the Allergy Vigilance Network. The global cost was estimated from the national data of hospital admissions: ICD-10 coding available for 2003, 2004 and 2005. RESULTS: Three work/classroom days were lost per patient. Diagnosis required oral challenge with hospitalization in 18% of cases. The estimated mean total cost was 1895 euros for food- and drug-related anaphylaxis (5610 euros for the most severe), and 4053 euros for Hymenoptera anaphylaxis. National statistics recorded 2575 patients in 2005; 22% more than in 2003. The estimated annual cost was 4,789,500 euros. The possible reasons for this being an under-estimate include: data coming only from hospitalized patients, poor identification by medical teams unfamiliar with ICD-10 codes, peri-operative anaphylaxis being insufficiently declared, rush-immunotherapy and maintenance treatments for Hymenoptera anaphylaxis. Similarly, the extra cost of cow milk substitutes, as well as insurance costs where deaths are followed by litigation were not taken into account. CONCLUSIONS: The mean cost of anaphylaxis was 1895-5610 euros in nonfatal patients. The prevalence was under-estimated because of many biases, leading to under-estimation of the national cost. Further studies would be necessary to evaluate the value of preventive strategies.

Oral desensitization in children with milk and egg allergies obtains recovery in a significant proportion of cases. A randomized study in 60 children with cow's milk allergy and 90 children with egg allergy.

BACKGROUND: Food allergy is treated by avoidance diets in order to prevent anaphylactic reactions and to cure chronic associated symptoms. However, the natural history is left unchanged. OBJECTIVE: To search for a beneficial effect of an oral desensitization protocol to allergenic foods in IgE-dependent milk or egg allergies in children. METHODS: 60 children with documented cow's milk allergy (13 months-6.5 years), and 90 children with egg allergy (12 months-8 years), were consecutively included after 6-12 months of avoidance diet, if a SBPCFC to 60 ml milk (60 ml) or to 965 mg of raw egg white was negative. They were randomized for uninterrupted avoidance or oral desensitization (group A or OD). Six months later, a new SBPCFC was performed with, up to 200 ml of milk or 7g of raw egg white. Prick tests and specific IgE levels were carried out simultaneously. RESULTS: Data were obtained for 57 children with CMA (30 A and 27 OD), and 84 children with EA (35 A and 49 OD). The two groups (AD or OD group) were similar with regard to means of ages, the size of PT wheals and the level of IgEs at baseline. MILK ALLERGY: A SBPCFC to milk was positive in 11.1% of those following OD vs. 40% after A (p < .025). The size of PT decreased after OD and increased after A (-3.4 mm vs. +0.84 mm; p < .002). EGG ALLERGY: The SBPCFC to egg was positive in 30.6% after OD vs. 48.6% after A (p < .1). After 6 months, in the OD group, the mean size of the PT and the level of specific IgE were significantly reduced compared to the A group. In the A group, the threshold of reactivity was often lower, or more serious symptoms were observed. CONCLUSION: Oral desensitization helps the egg and milk allergic children to overcome their allergies. Since the avoidance of these foods is likely to increase sensitization as well as to lower the threshold of reactivity, an active treatment is required. Further attempts to standardize the procedures of oral desensitization are expected.

Risk of allergy to food proteins in topical medicinal agents and cosmetics.

The risk of allergy to food proteins in cosmetics and topical medicinal agents is poorly evaluated. IgE dependent contact urticaria and contact dermatitis are observed. Eleven cases (7 infants and 4 women) are reported. Wheat, egg, oats, milk, peanut proteins are incriminated by prick-tests or atopy patch-tests. Cases are related to a previous food allergy and other ones may indicate primary sensitization to topical creams mainly used for skin care of atopic dermatitis. A consecutive exercise induced anaphylaxis to wheat and a long lasting sensitization to wheat have been observed. A clear and accurate identification of food allergens in cosmetics and topical agents is necessary. Given the hyper-permeability of infant skin, topical products containing food proteins of known allergenicity are contra-indicated for neonates, and for infants with atopic dermatitis, which may be associated with skin hyper-permeability.

Food-dependent exercise-induced anaphylaxis--update and current data.

Exercise-induced anaphylaxis (EIA) is defined as the onset of allergic symptoms during, or immediately after, exercise, the clinical signs being various degrees of urticaria, angioedema, respiratory and gastrointestinal signs and even anaphylactic shock. Food-dependent exercise-induced anaphylaxis (FDEIA) introduces food in the syndrome and is revealed by a chronological sequence in which food intake, followed by exercise, induces symptoms after a varying period. When the food intake and the exercise are independent of each other, there are no symptoms. FDEIA is not very frequent. Identifying the culprit food allergen depends on the patient's eating habits. Crustaceans and wheat flour are the two commonest but others foods can be implicated. The patho-physiology of FDEIA has not been clearly established but it appears to result from degranulation of mast cells. As with food allergy, FDEIA diagnosis is based on interview, skin and biological tests and challenge. For the clinical signs of allergy, antihistamines, corticosteroids and epinephrine may be administered. Prophylaxis aims to prevent a recurrence; the patient should be given an emergency kit to deal with any recurrent episode. After the food allergen has been identified, it should be avoided for at least 4 to 5 hours before any exercise.

The risk of systemic reactions to skin prick-tests using food allergens: CICBAA data and literature review.

Prick-tests to foods are usually carried out as the first step in the diagnosis of food allergy. Severe anaphylaxis accounts for 4.9 % of allergies in children and occurs more frequently in adults, raising the possibility of systemic reactions to prick-tests in highly sensitized people. Several studies published in the literature have used commercial extracts. As for airborne allergens, concentrations causing a skin reaction of 15 mm do not present a risk of systemic reactions. Prick-tests to native foods--prick-in-prick tests--have been less extensively studied. The CICBAA1 data, from 1,138 food allergic patients of all ages, cover 34,905 prick-in-prick tests to foods. The wheal of these prick-tests has been regulary registered. The risk of systemic reactions can be evaluated at 0.008 %. There were no severe reactions and anti-histamine and corticosteroid therapy were sufficient. These results are similar to those of the large study in 2000 carried out by Devenney in neonates (0.005%). A review of the literature reveals only a few severe reactions in adults. The authors draw attention to the necessary precautions: temporary contra-indication for skin prick-tests in children and adults with grade 3 or 4 asthma, with particular attention to such foods as all kinds of nuts, fish, etc.

Food allergens submitted to compulsory food labelling in the 50 highest-selling drugs in France.

Many active ingredients and excipients present in allopathic drugs derive from food allergens normally associated with compulsory food labelling. This study was undertaken to evaluate the presence of these components in the various pharmaceutical formulations of the 50 highest-selling drugs in French pharmacies in 2002 (in quantity and/or value), and to assess their labelling on the packaging of these drugs. The 174 pharmaceutical formulations of 86 drugs were studied and the composition of each one was identified using data-processing software. An excipient deriving from an allergen with obligatory labelling in food is present in 58.6% of the studied pharmaceutical formulations. Almost one third (32.2%) of these medications are correctly labelled since the excipients in question are already known to have adverse effects. This study demonstrates the actual presence of components derived from allergens with compulsory food labelling in the 50 highest-selling p maceutical products in France (in value and/or volume). Given the absence of clear labelling of food allergens in drugs, allergologists must inform both the medical and public communities of this potential risk. It is equally important that the pharmaceutical laboratories implement clear, informative labelling of food allergens, similar to that of the food industry.

Prevalence of peanut sensitization in a population of 4,737 subjects--an Allergo-Vigilance Network enquiry carried out in 2002.

A total of 4,737 people consulting allergologists were routinely tested for peanut sensitization. The study involved 84 allergologists in the Allergo-Vigilance Network over a period of 30-60 consecutive days. Investigation procedures were identical. Results classified subjects into four groups according to the clinical history and prick-tests to common inhalants: group 1: subjects suspected of having a food allergy; group 2: subjects with ongoing atopic disease; group 3: subjects with an underlying predisposition to atopy, as showed by one or more positive results to prick-tests with airborne allergens; group 4: non atopic subjects. The sensitization rates were 22.7%, 8.7%, 4%, and 0.4% respectively. Assuming that 25% of the French population is allergic the rate of sensitization to peanut in the general population should be between 1% and 2.5%. Considering a ratio of 3.3 between sensitization and clinical allergy as plausible, the prevalence of peanut allergy could be 0.3% to 0.75% of the French population. This figure is lower than that for the UK, the US and Canada (0.8% to 1.5%). The correlation between the data in this study and those from previous epidemiological studies validates the methodology used in this type of enquiry. One of the aims of the Allergo-Vigilance Network set up in 2001 is to collect data from a large number of people. We present here the results of a study carried out in 2002 by 84 allergologists in the Allergo-Vigilance Network. The primary aim was to assess the prevalence of peanut sensitization in the French population seeking treatment for various allergic disorders. The second objective was to determine whether there was any difference in risk of peanut sensitization in people with ongoing atopic disease, in those with an underlying predisposition to atopy (shown by positive prick-tests) and finally in non atopic people.