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Results for “Radioallergosorbent Test”

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At least 307 records · Page 17Linked to original sources

PubMed1989

Absorption of egg antigens by the gut observed by oral Prausnitz-Küstner (Walzer) reaction in atopic dermatitis.

Sera from 50 children (27 boys and 23 girls, under the age of 3 years) with atopic dermatitis allergic or not to hen's egg shown by skin test or radioallergosorbent test (RAST) were passively transferred to recipients which were then challenged with injection of egg antigen (Prausnitz-Küstner (P-K) test) or with ingestion of a raw egg (oral P-K test). Thirty-one patients showed positive P-K reaction with serum titers from 2 to 8,192. Fifteen of the P-K positive cases were also positive in the oral P-K test with titers from 2 to 256. The ratio of the oral P-K titer and the P-K titer in each positive case was from 1:2 to 1:32. The results indicate that a high percentage of atopic dermatitis patients with egg allergy have IgE antibody in the serum capable of reacting with an ingested egg.

Antigens↗

PubMedDate not supplied

Psyllium anaphylaxis.

Allergic reactions from handling psyllium have been reported since 1970. Health professionals and workers in laxative-manufacturing plants are at greatest risk. Sensitized people are at risk of life-threatening anaphylactic reactions. Two illustrative cases are presented. The first is A 39-year-old female dialysis nurse with a 3-year history of nasal and eye symptoms from exposure to psyllium. She obtained an over-the-counter psyllium bulk laxative, took it for constipation and developed flushing, tachycardia, urticaria, angioedema, laryngeal edema, and lightheadedness. An epicutaneous skin test and radioallergosorbent test for psyllium were both strongly positive. The second is a 42-year-old female nurse with a history of asthma who had allergic nasal and eye symptoms while dispensing psyllium. She received a prescription for crystallized psyllium, took it by mouth, and developed immediate flushing, tachycardia, urticaria, and angioedema. With subsequent ingestion of psyllium she had, in addition, severe wheezing, lightheadedness, and loss of consciousness. A psyllium epicutaneous skin test was strongly positive. These patient reports illustrate the risk of severe allergic reactions in sensitized people. Ingestion by sensitized people, such as from a routine postoperative and postpartum order, is potentially dangerous.

Adult↗

PubMed1994

Comparison of Naphcon-A and its components (naphazoline and pheniramine) in a provocative model of allergic conjunctivitis.

A double-masked, randomized, parallel group, placebo-controlled study demonstrated the efficacy of Naphcon-A (naphazoline HCl 0.025% and pheniramine maleate 0.3%). Seventy-two patients with a documented positive skin test or radioallergosorbent test were recruited. Three groups of 24 patients each received 1 drop of Naphcon-A instilled in one eye, and 1 drop of either naphazoline, pheniramine, or placebo in the other eye. After the instillation of test medication, a titrated dose of ragweed antigen was administered bilaterally, and ocular signs and symptoms were evaluated 10, 30, and 120 minutes later. All patients (excluding 4 who had persistent symptoms attributable to ragweed) were rechallenged with ragweed antigen at 120 minutes to assess the duration of action of the test medications. Naphcon-A was significantly more effective than placebo, naphazoline, and pheniramine in reducing redness. Naphcon-A and pheniramine were equally effective in relieving itching.

Adult↗

PubMed1999

Food allergy and food intolerance in childhood.

Food intolerance is a reproducible adverse reaction to a specific food ingredient that is not psychologically based. Food allergy is a form of food intolerance in which there is evidence that the response is caused by an immunological reaction to food. Other mechanisms of food intolerance include enzyme defects (e.g. lactase deficiency), pharmacological effects (e.g. histamine), toxic properties (e.g. haemagglutinating lectins) and irritants (e.g. spices). Food allergy in children is a highly contentious subject and there is often a striking lack of published evidence from which to base clinical decisions. The true prevalence of food allergy in children is unknown, although there is evidence of an increasing incidence of allergic reactions to some foods, especially peanuts. Our understanding of why some children are unable to tolerate certain foods (e.g. cow's milk, egg), or how they grow out of this intolerance, is very poor. Symptoms of food allergy in children are diverse and include vomiting, poor weight gain, abdominal pain, malabsorption, cough, wheeze, rhinitis, atopic eczema, urticaria and angioedema. Despite the lack of objective data to support the notion that food intolerance contributes to behaviour in children, this is a belief firmly held by many parents and some professionals. The gold standard for diagnosing food intolerance is the double-blind placebo-controlled food challenge (DBPCFC). There is often a poor correlation between the results of food provocation tests and those of skin prick tests of radioallergosorbent tests for specific food antibodies. For proven food allergy, elimination diets are the mainstay of management. In children these must be closely supervised to avoid nutritional deficiency and compromise of growth. Some children who have had severe (anaphylactic) reactions after food need to have a supply of self-injectable adrenaline made available to their parents and teachers and must also practice strict avoidance of the offending food.

Diet↗

PubMedDate not supplied

Severe tomato allergy (Lycopersicon esculentum).

Although tomatoes are a commonly consumed food, severe allergic reactions to tomatoes are unusual or rarely reported. Previously reported allergic manifestations to tomato include urticaria/angioedema, dermatitis, oral allergy syndrome, rhinitis, and abdominal pain. The aim of this study was to report two patients with significant immediate hypersensitivity reactions to tomato and characterize the responsible allergen. We reviewed the history and documentation of tomato-specific immunoglobulin E (IgE) of two patients with adverse symptoms after ingesting tomato. Fresh tomato extracts prepared from the skin, seeds, and flesh of red, ripe tomatoes were evaluated for total protein content and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was performed to characterize the tomato protein. IgE enzyme-linked immunosorbent assay (ELISA) using the patients' serum against the various tomato extracts was accomplished and IgE immunoblot was performed. Percutaneous skin tests or radioallergosorbent tests (RASTs) were positive to tomato in both patients. Both adults experienced laryngeal edema and one had anaphylaxis. Similar total protein contents were found in each of the tomato extracts and gel electrophoresis revealed similar protein profile for skin and seed extracts with protein bands discernible at molecular weights of 21, 33, and 43 kDa. One patient reacted specifically to a 43-kDa protein band on IgE immunoblot. The two cases show that severe allergic reactions to tomato occur in adults and one is associated with IgE binding to a 43-kDa protein.

Adult↗

PubMed2004

Clinical presentations of patients sensitive to natural rubber latex.

BACKGROUND: Eczematous reactions to natural rubber latex (NRL) have been associated with both immediate and delayed hypersensitivity. OBJECTIVE: To determine clinical cases that might require testing for immediate sensitivity or patch testing for delayed hypersensitivity to latex fabric. METHODS: Patients with suspected sensitivity to NRL were given in vitro testing by radioallergosorbent test (RAST) or ImmunoCAP test and if negative, were prick-tested. If prick-test results were negative and the patients were still available, patch testing was done with latex glove fabric. Case histories of persons with positive results on RASTs, ImmunoCAP tests, prick tests, and patch tests were reviewed for clinical presentation and relevance. RESULTS: Of 92 persons with positive responses, 26 had positive RAST results, 26 had positive ImmunoCAP test results, 33 had positive prick-test results, and 7 had a positive patch-test result. Presentations included hand urticaria or eczema (46 patients), eyelid dermatitis (14), shoe dermatitis (10), atopic eczema (6), waistband dermatitis (5), clothing dermatitis (3), contact eczema to elastic in a mask (2), urticaria to a phlebotomy tourniquet, and eczema over the elbows and from an elastic bandage used for occlusive dressing therapy. Several other presentations were less likely to be relevant. CONCLUSION: Persons with putative contact dermatitis in areas that may come into contact with NRL deserve not only to be patch-tested with rubber chemicals but also to be tested for immediate sensitivity and, if results are negative, to be patch-tested with NRL.

Adolescent↗

PubMed1990

Food allergy and atopic eczema.

As a contributing factor, certain foods can provoke skin lesions in some patients with atopic eczema. In newborns with an increased risk of atopy, exclusive breastfeeding during the first months of life and delayed introduction of solid food seem to inhibit or to retard the manifestation of atopic disease. The pathomechanism of provocation of eczema by food has not yet been elucidated. The frequent finding of specific immunoglobulin E (IgE) antibodies to the offending food items suggests that immediate type allergic reactions may be involved. Furthermore, other allergic or nonimmunologic (pseudo-allergic) mechanisms have to be considered. History taking, skin tests, and radioallergosorbent test (RAST) may provide some information with regard to eliciting food, but these procedures usually are not sufficient to obtain a conclusive diagnosis. Oral challenge tests have to be performed in a controlled manner in order to identify food items that are not tolerated and thus have to be avoided. As most of the patients react only to one or two food items and as these often differ from one patient to another, undirected exclusion diet regimens are unnecessary and unethical. Furthermore, such diets bear the risk of malnutrition and of anaphylactic reactions after reintroduction of allergenic food. Dietary recommendations in atopic eczema have to be based on a careful allergological workup of the individual patient.

Dermatitis, Atopic↗

PubMed1995

Diet regimen in the treatment of food allergy.

Adverse reactions to food may be mediated by immunological or non immunological mechanisms. The term "food allergy" describes an event in which a definite immunopathological process can be demonstrated and a cause and effect relationship must be present. Symptoms and signs of food allergy may appear in any organ system, depending in part on the age of the subject and on the allergen involved. At present it is generally agreed that the only effective therapy for food allergy is strict elimination of the offending food antigen. Institution of a food elimination diet should be considered comparable to prescribing a medication, which carries along definite risk-benefit ratio. Consequently, appropriate diagnostic measures base on history, skin test, or radioallergosorbent test (Rast) and blind food challenges, must be utilized before implementing special diets. The allergist and other health care professionals must recognize the advantages of elimination diets (improvement of symptoms) as well as disadvantages (increase of the time required to purchase food and prepare meals, impossibility to eat at restaurants, at friends' houses or at school with consequent possible social isolation, nutritional disorders) and choose the most appropriate elimination diet.

Child↗

PubMed1996

Design of an optimally-diagnostic skin test solution for diagnosis of sensitivity to timothy grass (Phleum pratense) pollen.

BACKGROUND: Although most of the common allergen extracts that are used for diagnosis of type 1 hypersensitivity are now well standardized, this gives no assurance that they are within the concentration range that gives the best chance of a true diagnosis. OBJECTIVE: The objective of this study was to identify the most appropriate concentration range of timothy grass pollen Phleum pratense extract to diagnose sensitivity to this pollen correctly through skin-testing. METHODS: Dilutions of a well-standardized extract were made and used to skin test "true' positive and "true' negative populations of subjects as identified by case history, challenge tests and radioallergosorbent test (RAST). Weal diameters were measured and the data were submitted to receiver operating characteristics (ROC) analysis. For any particular weal size cut-off, the optimal diagnostic concentration (ODC) range was thus calculated. RESULTS: A 3 mm weal diameter cut-off was chosen as an appropriate size for routine diagnosis. Therefore the ODC range at this diameter was used to establish a product target concentration and specification for formulation of the diagnostic reagent. This method of allergen extract standardization can lead to a true-biological unitage that can be used for labelling purposes. CONCLUSION: The optimum concentration range at which to formulate an allergen extract, in terms of an in vitro immunologically based assay, can be determined by carrying out ROC analysis of the results of clinical studies as described in this communication. Diagnostic units (DU), are now used by us for labelling of such final formulations which conveys the information that the product is at the most appropriate concentration for diagnosis.

Allergens↗

PubMed1997

Immediate and delayed skin allergy from cow dander.

BACKGROUND: Cow dander is the most common cause of occupational contact urticaria in Finland. Occasionally cow dander also causes allergic contact dermatitis, which can be revealed by patch testing with cow dander. OBJECTIVE: A patient with a combined type I and type IV allergy to cow dander is the subject of this report. RESULTS: She had intense pruritus, whealing, and severe dermatitis, but no respiratory symptoms. Skin tests and radioallergosorbent test indicated that she had both type I and type IV allergy to cow dander. CONCLUSION: Increasing numbers of cases with both type I and type IV allergy are reported, but the mechanism is not clear. In our clinic, we classify immediate reactions as contact urticaria if the clinical picture involves whealing, and as protein contact dermatitis if dermatitis dominates the clinical picture. If delayed allergic patch test results are obtained, we consider it allergic contact dermatitis.

Allergens↗

PubMed1998

Use of immunotherapy in a primary care office.

Immunotherapy has been used for over 80 years. It is a safe and effective therapeutic intervention for allergic rhinitis, but its use in the treatment of asthma is more controversial. Patients with unstable asthma are at increased risk of adverse effects from immunotherapy; therefore, if immunotherapy is used in such patients, it should be instituted cautiously. Indications for immunotherapy include evidence of IgE-mediated disease and positive results on skin tests or radioallergosorbent test (RAST). In addition, before immunotherapy is considered, measures to avoid exposure to offending agents and drug therapy should have failed to provide relief of symptoms. Before administering immunotherapy in the office, physicians should be knowledgeable about the use of immunotherapy and the treatment of anaphylaxis, and should have ready access to the equipment needed to avert anaphylaxis.

Asthma↗

PubMed1992

Comparison of the residual allergenic activity of six different hydrolyzed protein formulas.

The residual allergenic activity of protein hydrolysates contained in marketed "hypoallergenic" infant formulas can be determined both by in vivo methods (skin prick tests, provocation tests) and by in vitro methods (radioallergosorbent test, radioallergosorbent inhibition, crossed radioimmunoelectrophoresis, basophil histamine release). In general, whey hydrolysates containing a high percentage of larger peptides have the highest capacity to induce positive skin test and provocation test results, and to bind to human serum IgE antibodies of cow milk-sensitive children. Casein hydrolysates appear to have very little residual allergenic activity. Before hypoallergenic formulas are prescribed for cow milk-sensitive children, individual testing (e.g., skin test, challenge tests) is recommended.

Child↗

PubMed1984

Allergy to semisynthetic penicillins in cystic fibrosis.

Allergic reactions to anti-Pseudomonal penicillin derivatives are an increasing problem in therapy of cystic fibrosis lung disease. We evaluated 15 patients, ages 12 to 37 years, with documented allergic reactions to carbenicillin, ticarcillin, or piperacillin. Intradermal skin test reactions were positive for benzylpenicillin in seven patients, penicilloyl-polylysine in one, and ticarcillin or piperacillin in eight, for a total of 11 of 11 tested. Results of radioallergosorbent testing to penicilloyl conjugates were positive in eight of 14 patients and equivocal in four others. Overall, skin tests or RAST results were positive in 13 of 15 patients. All patients were desensitized with a semisynthetic penicillin by continuous serial intravenous infusion of 10-fold dose increments, beginning with 10(-6) of the therapeutic dose. Desensitization was successful in 25 of 26 instances. After intravenously administered therapy, maintenance of desensitization with dicloxacillin orally was unsuccessful in four of six patients. We conclude that (1) allergy to semisynthetic penicillins in cystic fibrosis usually is IgE mediated; (2) such allergy can be evaluated by skin testing; (3) it can be safely and in most cases successfully treated by intravenous desensitization; and (4) allergic patients should be desensitized on each subsequent admission for intravenously administered therapy.

Adolescent↗

PubMed1997

Allergic diagnosis: skin testing and rast.

In a minority of patients with allergic rhinitis, diagnosis of the offending allergens is necessary for control of symptoms. Skin endpoint titration (SET) testing, the most advanced form of skin testing, and the radioallergosorbent test (RAST) are the only two diagnostic tests that give quantitative results upon which to base immunotherapy. Patients who undergo diagnostic testing must understand the commitment involved in a program of immunotherapy. This review hopes to enable clinicians to better understand the techniques of skin testing and RAST and how and when these tests may be of use to their patients suffering from allergic rhinitis.

Humans↗

PubMed1983

Value of the case history in the diagnosis of allergic state and the detection of allergens.

Detailed histories taken in eighty-one patients suffering from perennial asthma and rhinitis were analysed independently by three trained allergists and their conclusions were compared to the results of three tests: (1) concentration of total serum IgE; (2) skin tests and (3) radioallergosorbent test (RAST). In eleven patients (14%), the three investigators disagreed when estimating the allergic nature of the symptoms. Ten out of forty-four patients (23%), unanimously predicted not to be allergic, had high levels of total serum IgE and skin tests and RAST clearly positive for one or more allergens. The allergists suspected 47% of the allergens detected by skin tests and 55% of those detected by RAST. The case history was the test which most often gave information at odds with that suggested by the other three tests. Our study indicates therefore that a case history not even suggestive of allergy should be complemented by additional tests.

Adolescent↗

PubMed1979

Anaphylaxis to sunflower seed.

The clinical and immunological investigation of three patients with an acute anaphylaxis after ingesting commercial varieties of sunflower seeds is presented. Specific IgE-mediated hypersensitivity has been demonstrated in all three patients to sunflower seed extract by history, direct skin tests, and positive radioallergosorbent test (RAST) titers. RAST inhibition was positive in two patients tested. Similar tests on controls were negative.

Acute Disease↗

PubMed1984

Allergy to ethylene oxide in chronic hemodialysis patients.

Almost a decade ago, a single chronic hemodialysis patient in Hamilton, Ontario, Canada, who was experiencing recurrent acute reactions during hemodialysis was found to have become allergic to ethylene oxide gas (EO). This observation recently provided a stimulus to examine the possibility that others exhibiting acute allergic-type reactions during hemodialysis might be similarly sensitized. Serum was obtained from 27 reacting patients and tested in a radioallergosorbent test (RAST) for antibodies to EO. The test was positive for 22 of these sera. EO-related specificity of the antibodies was confirmed. However, EO sensitization was not found in other hemodialysis patients with isolated eosinophilia. In a survey of the current Hamilton chronic hemodialysis population for EO-related antibodies, 9% had a positive allergy skin test and 12% had a positive RAST. The sensitized individuals had no distinctive symptoms. The lesser sensitivity of the skin test contrasts with usual findings in allergic individuals; however, the use of histamine and codeine in chronic hemodialysis and peritoneal dialysis patients might well explain a reduced sensitivity of the EO-related allergy skin test. Chronic peritoneal dialysis could not be invoked as a source of sensitization. None of these patients had a positive skin test or RAST for EO-related antibodies that could be attributed to peritoneal dialysis.

Antibodies↗

PubMed1980

Inhalant allergy due to crickets.

Two employees developed allergic rhinitis and bronchial asthma which was occupationally related to raising crickets. Skin tests, bronchial challenge, radioallergosorbent test (RAST), in vitro histamine release and a passive transfer test supported the presence of type I hypersensitivity to cricket allergens. Skin tests of other employees and patients of an allergy clinic suggested that cricket emanations are potent allergens.

Antibody Specificity↗