"Nasal Allergen Challenge (NAC): Practical Aspects and Applications from an EU/US perspective: A Workgroup Report of the AAAAI Rhinitis, Rhinosinusitis and Ocular Allergy Committee"

Nasal allergen challenge (NAC) is applied in a variety of settings (research centres, specialty clinics and hospitals) as a useful diagnostic and research tool. NAC is indicated for diagnosis of seasonal and perennial allergic rhinitis, local allergic rhinitis, occupational rhinitis, to design the composition of allergen immunotherapy in polysensitized patients and to investigate the physio-pathological mechanisms of nasal diseases. NAC is currently a safe and reproducible technique, although it is time and resource consuming. NAC can be performed by a variety of methods, but the lack of a uniform technique for performing and recording the outcomes, represents a challenge for those considering NAC as a clinical tool in the office. The availability of standardized allergens for NAC is also different in each country. The objective of this workgroup report is to review the current information about NAC, focusing on the practical aspects and application for diagnosis of difficult rhinitis phenotypes (e.g. local allergic rhinitis, occupational rhinitis), taking into account the particular context of practice in the United States and the European Union.

Long-term safety and efficacy of triamcinolone acetonide aqueous nasal spray for the treatment of perennial allergic rhinitis

This 12-month, multicenter, open-label study to assess the long-term safety and efficacy of triamcinolone acetonide (TAA) aqueous nasal spray for perennial allergic rhinitis (PAR) symptom relief was a continuation of a 4-week, double-blind study. Patients who received TAA Aqueous (220 micrograms/day) during the 4-week, double-blind study continued with the same treatment for the open label study; those randomized to placebo during the 4-week, double-blind study received TAA Aqueous (220 micrograms/day) for the open-label study. Dose reduction to 110 micrograms/day was allowed if it was felt that symptom relief would be maintained. Safety was assessed by daily diary entries and clinical laboratory results. Long-term efficacy was assessed by visual analog scale (VAS). Of the 172 patients who began the open-label study, 94.2 percent completed 3 months of treatment, 83.6 percent completed 6 months, and 62 percent completed 12 months. PAR symptom relief improved progressively throughout the study. Adverse events were generally mild or moderate and consistent with long-term use and winter symptoms. The most common adverse events were pharyngitis (32 percent of patients), rhinitis (28.5 percent), headache (22.1 percent), and epistaxis (18 percent). Adverse events related to the local effects of the study medication were similar to those observed in long-term studies with TAA aerosol. The aqueous nasal spray formulation of triamcinolone acetonide was well tolerated and continued to relieve nasal symptoms with long-term use in adolescent and adult patients with PAR.

Triamcinolone acetonide aqueous nasal spray for the treatment of patients with perennial allergic rhinitis: a multicenter, randomized, double-blind, placebo-controlled study

In this multicenter, randomized, double-blind, placebo-controlled study, 178 patients with symptoms of perennial allergic rhinitis (PAR) were treated with either triamcinolone acetonide (TAA) Aqueous nasal spray (220 micrograms once daily) or placebo for 4 weeks. Symptoms of PAR (nasal stuffiness, nasal discharge, sneezing, nasal index, and nasal itching) were evaluated throughout the treatment period through the use of patient diaries. In addition, both patients and physicians completed independent global evaluations of treatment efficacy at the conclusion of the study. TAA Aqueous provided clinically and statistically (P < or = 0.05) greater improvements in nasal stuffiness, sneezing, nasal index, and nasal itching over the 4-week study period than did placebo. Significant improvements in sneezing (P = 0.022) were observed as early as the first day (within 12 to 16 hours based on treatment in the morning and assessment of symptoms at bedtime), and in the nasal index (P = 0.009) by the third day after treatment with TAA Aqueous. Patients' and physicians' global evaluations of overall efficacy were concordant: 65% of patients rated their nasal symptoms greatly or somewhat improved with TAA Aqueous compared with 48% in the placebo group; physicians rated 66% of patients as having greatly or somewhat improved symptoms with the study drug compared with 48% of patients who received placebo. Adverse events were mild and the incidences were comparable for both groups; no significant changes in vital signs or clinical laboratory parameters were observed. This study demonstrated that TAA Aqueous administered once daily was well tolerated and provided relief of PAR symptoms in adults and adolescents.

Latex allergen in respirable particulate air pollution

OBJECTIVE

Urban air samples contain numerous irregular respirable black particles, which may be airborne tire fragments. A major component of tires is natural latex. Proteins of natural latex can act as adjuvants and as antigens capable of eliciting immediate hypersensitivity, making their presence in particulate air pollution an important clinical issue.

METHODS

Particulate air pollutants were collected by volumetric sampling devices and characterized by optical microscopy, chemical solubility tests, and mass spectrometry. Extracts of rubber tire fragments were tested for elutable latex antigens by antibody inhibition assays.

RESULTS

Identification of latex in air samples and milled material from automobile tires was supported by mass spectrometry results and was further confirmed by physical appearance and chemical solubility studies. Competitive immunoassay confirmed the presence of extractable latex antigens from rubber tire fragments.

CONCLUSIONS

Latex antigens are extractable from rubber tire fragments, which are abundant in urban air samples. Given the adjuvant and sensitizing effects of latex, these airborne particles could contribute, through direct and indirect mechanisms, to the increase in both latex sensitization and asthma. The impact of these particles should be considered in the issue of morbidity and mortality rates associated with respiratory diseases and air pollution.

Immunoassay of specific IgE: use of a single point calibration curve in the modified radioallergosorbent test

Interest in immunoassay standardization has prompted development of specific IgE assays reporting results related to the international IgE reference. To examine the single point calibration curve employed in the modified RAST assay (MRT) to convert MRT counts to IgE units, independent dilutions of a 25 kU/L total IgE reference and nine allergic sera (three each for short ragweed, cat, and timothy) were made in horse serum and assayed. In a log-log plot, the single point curve was, by definition, linear over its entire range; the dilution curve was curvilinear because of reagent system saturation, which was at 7 kU/L. Curves were not parallel (P less than .001). Allergen-specific dilution curves showed saturation points at values similar to or less than the total IgE system. The linear portions of these curves paralleled the total IgE dilution curve but not the single point curve. This lack of parallelism would have resulted in varying magnitudes of error in estimation of IgE antibody levels in the upper and lower assay ranges, and would imply a lower detection limit for IgE than that which the assay actually has. Modified RAST assay is not appropriate in research or a clinical situation in which accurate quantitative results are needed. Modified RAST assay would furthermore be an inappropriate means of assigning units to proposed reference preparations for standardization.

The histamine content of allergen extracts

The histamine content of 108 inhalant, food, and venom extracts from four commercial sources was measured by chemical (glass fiber-based) and immunologic (competitive RIA) methods. Histamine was present in 64 of 76 inhalant extracts (range, 0.005 to 7.4 micrograms/ml), 20 of 26 food extracts (range, 0.16 to 23 micrograms/ml), and six of six venoms, 100 micrograms/ml (range, 1.0 to 38 micrograms/ml). Histamine was removed by treatment with diamine oxidase or dialysis of an extract. Repeat assay of selected extracts after addition of known amounts of histamine in the glass fiber-based method produced additive results, and glycerin- or phenol-extract preservatives did not affect assay performance. Timed extractions of dried-pollen grains demonstrated maximal histamine content at 30 seconds, suggesting that histamine is an inherent component of at least some pollens. Histamine found in some allergen extracts could, under extreme circumstances, produce false-positive results in skin testing and in basophil histamine release assays, and could affect the result of research that uses intact pollen or allergen extracts.

Comparison of skin testing and three in vitro assays for specific IgE in the clinical evaluation of immediate hypersensitivity

A new assay, Pharmacia CAP System (PCS), for allergen-specific IgE (sIgE) was evaluated in 198 new patients presenting with respiratory symptoms to an urban allergy practice. An experienced allergist examined each patient and clinically assessed sensitivity to timothy, short ragweed, Alternaria tenuis, cat, or D. farinae. Puncture and selected intracutaneous skin tests (ST) with these inhalant extracts were then performed. The physician again rated the likelihood of clinical sensitivity to each inhalant, and serum was obtained for sIgE measurements by Phadebas RAST, modified RAST, and PCS. Results of the three in vitro tests (IVT) correlated well with each other and generally agreed with physician assessments and ST results. Individual differences for extracts and assay methods were identified. A few patients with negative ST had positive IVT, but more patients with positive ST were negative by IVT. Modified RAST had greater sensitivity but less specificity than the other two IVT. Analysis of receiver operating characteristic curves showed that sensitivity of the three assays when compared at the 95% level of specificity, did not differ. This result suggests that the cutoff criterion for a positive modified RAST result is too low and should be reevaluated. Skin tests remain the most sensitive and specific test available. The Pharmacia CAP System is a clinically useful assay for sIgE and appears to be a clear advancement for IVT technology.

Assessment of nasal patency by rhinoscopic measurement of cross sectional nasal airway area: correlation with subjective nasal symptoms

Assessment of nasal patency by the recording of nasal symptom scores was compared with an objective method of determining nasal airway area using a fiberoptic rhinoscope. Sixty patients with active allergic rhinitis and nasal congestion requiring treatment were studied. Nasal symptoms were recorded and nasal airway area was measured before and at fixed time intervals after administration of either pseudoephedrine or oxymetazoline. Both methods detected a decongestant response to both drugs, and the symptom of congestion correlated with the measured nasal airway area. Rhinoscopic measurement of cross sectional nasal airway area is an objective method that may be used to complement other methods for evaluation of nasal patency.

Anaphylaxis to piñon nuts

A 21-year-old white male developed life threatening systemic anaphylaxis within seconds of ingesting a small amount of a cookie containing piñon nuts. Skin testing, ELISA, and basophil histamine release studies demonstrated piñon nut-specific IgE. Electrophoresis of the piñon nut extract demonstrated 30 bands, three of which (in the 66 to 68,000 dalton range) bound IgE in the patient's serum in an immunoblot. Ingestion challenge was not performed due to the severity of the patient's reaction. Although used for centuries in certain cultures, piñon nuts are now being eaten more frequently in the American diet. Physicians should be aware of the potential for anaphylactic reactions following ingestion of this food.

Evaluation of the safety and efficacy of multiple doses of azelastine to adult patients with bronchial asthma over time

Azelastine is a new oral antiasthma agent with bronchodilating and antiallergic properties. This 12-wk study compared azelastine (2, 4, 6, and 8 mg) and placebo given twice a day in asthmatics 12 to 60 yr of age requiring daily bronchodilator therapy. Patients were allowed albuterol aerosol, short-acting theophylline, and pseudoephedrine only as needed. The study was completed by 221 asthmatic subjects. No significant differences in symptoms, medication, or pulmonary function existed between groups at baseline. Analysis of the zero hour FEV1 before azelastine administration on eight occasions during the 12 wk of therapy indicated an increasing slope for azelastine 6 mg that was statistically different from that of placebo; similarly, the slope for azelastine 4 mg showed the same trend, but it did not reach statistical significance. All azelastine groups had significant reductions of as-needed medication after 1 wk; only in the 4-mg and 6-mg groups was this reduction sustained for 12 wk. Asthma symptom scores and peak expiratory flow measurements remained stable in the azelastine groups despite significant reductions in concomitant medication administration. Side effects were minor and included: altered taste (30.1 to 51.9%), drowsiness (6.0 to 16.9%), and dry mouth (3.8 to 6.1%). The occurrence of these adverse events decreased with time throughout the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Sensitivity to sulfited foods among sulfite-sensitive subjects with asthma

Eight individuals with asthma who had been diagnosed as sulfite sensitive on the basis of double-blind capsule-beverage challenges were subjected to challenges with various sulfited foods, including lettuce, shrimp, dried apricots, white grape juice, dehydrated potatoes (as mashed potatoes), and mushrooms. Four of these patients failed to respond to challenges with any of the sulfited foods. The other four patients experienced a decrease in pulmonary function on double-blind challenges with sulfited lettuce. Two of three of these patients reacted to challenges with dried apricots and white grape juice; the fourth patient has not yet been challenged with these products. Only one of these four patients reacted to challenges with dehydrated potatoes and mushrooms, and, in this case, the response to double-blind challenges with dehydrated potatoes was not consistent. None of the sulfite-sensitive subjects with asthma responded to challenges with sulfited shrimp. It is concluded that sulfite-sensitive subjects with asthma will not necessarily react after ingestion of sulfited foods. The likelihood of a reaction is dependent on the nature of the food, the level of residual sulfite, the sensitivity of the patient, and perhaps on the form of residual sulfite and the mechanism of the sulfite-induced reaction.

Vocal cord dysfunction: the importance of psychologic factors and provocation challenge testing

We present three case reports involving patients with vocal cord dysfunction. The onset of symptoms in one case was coincident with a generalized cutaneous reaction to penicillin with laryngeal involvement. The other cases had been misdiagnosed as food allergy and chemical sensitivity. We describe the psychologic factors in these cases in terms of the primary and secondary gain operative in the somatoform disorder of conversion reaction and emphasize the importance of belief and learned sensitivity in the induction of symptoms. The necessity of considering psychologic factors and the use of blinded, controlled, provocation challenges to evaluate subjective symptomatology is underscored. This study emphasizes the heterogenicity of clinical presentations involving vocal cord dysfunction and illustrates the value of fiberoptic-assisted examination of laryngeal function in conjunction with provocation challenge testing in establishing causal relationships for specific clinical symptoms.

Viral contamination of intradermal skin test syringes

Intradermal skin tests are often performed using a common syringe with multiple needles. Bacterial contamination of intradermal skin test syringes can occur as a result of apparent siphoning caused by needle changing. The bacterial contamination of the syringe can be prevented by flushing the contaminated needle prior to changing. In this study, two different needle changing techniques were examined using a polio virus contaminant. Viral contamination of the syringe was not prevented by flushing the infected needle prior to removal. All syringes were contaminated with virus regardless of needle changing technique. We, therefore, cannot recommend the continued use of a common syringe for intradermal skin tests between patients regardless of needle changing technique.

Rhinolaryngoscopy in the allergy office

Rhinolaryngoscopy is a valuable diagnostic and treatment assessment tool for the allergist. We present a method for office use of the rhinolaryngofiberscope and review our experience with 400 consecutive examinations.

Inhaled metabisulfite sensitivity

Sensitivity to an inhaled sulfite-containing solution was evaluated in 13 asthmatics and ten nonasthmatic controls. Three of the 13 asthma patients were known to be sensitive to ingested sulfite and ten were not sensitive. All three sulfite-sensitive patients developed bronchospasm following sulfite inhalation challenges. Four of the ten asthmatics not sensitive to ingested sulfite developed bronchospasm following sulfite inhalation. The control subjects showed no reaction to inhaled sulfite. This study demonstrated that all asthmatics sensitive to ingested sulfite developed bronchoconstriction with inhaled sulfite. Furthermore, sensitivity to inhaled sulfite was more common than sensitivity to ingested sulfite in asthmatic patients. Possible reasons for this difference are discussed.

Presence of sulfur dioxide in commonly used bronchodilator solutions

We detected a significant amount of SO2 released from commercially used bronchodilators, including isoproterenol (Isuprel; Breon Laboratories, Inc., New York, N. Y.), metaproterenol (Alupent; Boehringer Ingelheim, Ridgefield, Conn., or Metaprel; Dorsey Laboratories, Lincoln, Neb.), isoetharine (Bronkosol; Breon Laboratories, Inc., New York, N. Y.), and racemic epinephrine (Micronefrin; Bird Corp., Palm Springs, Calif.). During standard nebulization of these agents, SO2 concentration varied from 0.1 to 6.0 ppm. These levels are known to be bronchoconstrictive in asthmatic patients. We believe clinicians should be aware of this observation when sulfite-containing bronchodilators are used.