A comparison of the effect of diphenhydramine and desloratadine on vigilance and cognitive function during treatment of ragweed-induced allergic rhinitis.

BACKGROUND: Decrements in cognitive performance are associated with the use of sedating antihistamines. Most, but not all, second-generation antihistamines have been found to be nonsedating. OBJECTIVE: To examine the central nervous system (CNS) profile of a new second-generation antihistamine, desloratadine. METHODS: Subjects with ragweed-induced allergic rhinitis (aged 18-60 years) who demonstrated a predetermined severity of symptoms after priming with ragweed pollen in the Environmental Exposure Unit were randomized to receive a single dose of desloratadine, 5 mg; diphenhydramine, 50 mg; or placebo. A comprehensive battery of repeatable, automated neuropsychological tests was administered to subjects before treatment (symptomatic baseline) and 90 minutes after taking study medication. RESULTS: Both desloratadine (P = .04) and diphenhydramine (P < .01) alleviated the symptoms of allergic rhinitis compared with placebo, but treatment with diphenhydramine was associated with clinically meaningful decrements on all vigilance parameters (P < .05 for desloratadine-diphenhydramine contrasts). Also, subjects treated with diphenhydramine performed significantly worse than subjects given desloratadine or placebo across all cognitive domains evaluated. Most effect sizes for the mean desloratadine and diphenhydramine differences were between 0.4 and 0.8 (moderate to high). Stanford Sleepiness Scale scores also indicated significantly more somnolence with diphenhydramine vs desloratadine or placebo (P < .001). There were no significant differences on any of the cognitive parameters between subjects treated with desloratadine and those given placebo. CONCLUSIONS: Desloratadine improved ragweed-induced allergic rhinitis symptoms without adversely affecting performance. Diphenhydramine improved allergic rhinitis symptoms but caused significant decrements in vigilance and cognitive functioning. Thus, efficacy of antihistamine treatment must be balanced against the associated effects on CNS functioning.     

Effects of seasonal allergic rhinitis on selected cognitive abilities.

BACKGROUND: Many allergy patients complain of slowed thinking, memory problems, and difficulty sustaining attention during their allergy seasons. OBJECTIVE: This study evaluated the effect of symptomatic allergic rhinitis on speed of cognitive processing, ability to divide and sustain attention, working memory, and recent verbal memory. METHODS: Symptomatic ragweed-allergic rhinitis patients and nonatopic control subjects did cognitive testing in, out of, and in ragweed seasons. RESULTS: Test results indicate that, during ragweed seasons, allergic patients experience subtle slowed speed of cognitive processing but not deficits in attention and recent memory. Some patients also have difficulties in working memory. CONCLUSIONS: These findings suggest that having allergic reactions to ragweed pollen causes significant cognitive difficulties in a subgroup of patients.     

Circulating basophils in normal subjects and in subjects with hay fever

The relationship of hay fever symptoms and changes in the number of circulating basophils was studied in 12 subjects clinically sensitive only to ragweed and in 10 nonatopic subjects before, during, and after the ragweed season. Total white blood counts, absolute basophil counts, and symptom scores were recorded twice weekly from mid-June through October, 1974, and compared with the ragweed pollen count. The results indicated that the absolute and relative number of basophils were significantly elevated (p < 0.001) in the hay fever group when symptoms occurred. As the symptom score of the allergic group increased during the ragweed season, the number of basophils also increased, only to decrease to control values when symptoms subsided. The basophil counts of the atopic group were significantly higher than those of the nonatopic group during the control periods. The nonatopic group also showed a significant elevation of basophils during the ragweed season, but to a much lesser extent than the atopic group. It is concluded that: (1) subjects with symptomatic hay fever have a significantly elevated absolute and relative basophil count which correlates with the exacerbation and remission of symptoms; (2) nonatopic subjects also have a small but significant elevation of basophils during the ragweed season; and (3) the elevation of basophils in the atopic group during symptoms is significantly greater than in the nonatopic group during the ragweed season.     

Grass pollen immunotherapy as an effective therapy for childhood seasonal allergic asthma

BACKGROUND: Few studies have investigated the use of specific immunotherapy (SIT) for childhood seasonal allergic asthma. OBJECTIVE: We sought to examine the efficacy and safety of SIT with Alutard SQ grass pollen (Phleum pratense Alutard SQ; ALK-Abelló, H?rsholm, Denmark) in children with seasonal allergic asthma. METHODS: A randomized, double-blind, placebo-controlled study assessing the efficacy of grass pollen SIT over 2 pollen seasons was performed. Children (3-16 years) with a history of seasonal allergic asthma sensitized to grass pollen (P pratense) and requiring at least 200 microg of inhaled beclomethasone equivalent per day were enrolled. Subjects with symptomatic asthma or rhinoconjunctivitis outside the grass pollen season were excluded. The primary outcome measure was a combined asthma symptom-medication score during the second pollen season. Secondary outcome measures included end-point titration skin prick testing and conjunctival and bronchial provocation testing to allergen, sputum eosinophilia, exhaled nitric oxide, and adverse events. RESULTS: Thirty-nine subjects were enrolled. Thirty-five subjects provided data for analysis. The use of SIT was associated with a substantial reduction in asthma symptom-medication score compared with that after placebo (P = .04). There were also significant reductions in cutaneous (P = .002), conjunctival (P = .02), and bronchial (P = .01) reactivity to allergen after SIT compared with that after placebo. The 2 groups had similar levels of airway inflammation, despite a trend toward less inhaled steroid use in the active group. No serious adverse events were reported, and no subjects withdrew because of adverse events. CONCLUSION: The study has shown that SIT is effective and well tolerated in children with seasonal allergic asthma to grass pollen.     

Effect of progression of disease on cognitive performance in HIV/AIDS

BACKGROUND: HIV infection causes a range of cognitive and behavioral symptoms that become more frequent and severe as the immune system deteriorates and symptomatic illness ensues. OBJECTIVE: To determine the impact of disease progression on cognitive abilities of Nigerian Africans who present in the HIV/AIDS clinic of the University Teaching Hospital, Benin City, Nigeria, using the CD4 levels as the measure of disease progression. METHODS: A total of 288 subjects comprising 96 randomly selected symptomatic AIDS patients, 96 randomly selected asymptomatic HIV-positive patients and 96 HIV-negative controls participated in the study. Enzyme-linked immunosorbent assay (ELISA) method was used to detect HIV infection, and CD4 levels were obtained for all subjects. The Community Screening Interview for Dementia (CSI 'D') was used to assess cognitive performance of subjects. Subjects were matched for age, sex and level of education. RESULTS: Each category of subjects comprised 48 males and 48 females. The mean ages were 32.94 +/- 8.0 years, 31.47 +/- 6.7 years and 33.56 +/- 7.1 years for the controls, asymptomoatic HIV-positive and symptomatic AIDS subjects respectively (p = 0.127). The mean CD4 levels were 684 +/- 44/microL (controls), 284 +/- 62/microL (asymptomatic HIV positive) and 142 +/- 36/microL (symptomatic AIDS). The mean CS1 'D' scores were 66.46 +/- 1.90 (controls), 66.31 +/- 2.14 (asymptomatic HIV positive) and 56.62 +/- 4.23 (symptomatic AIDS). CONCLUSION: Cognitive abilities of HIV/AIDS patients decline as the disease progresses. This is reflected in the cognitive performances of the symptomatic AIDS patients. The lower the CD4 levels, the worse the cognitive deficits. There was, however, no significant difference in the performance of asymptomatic HIV-positive patients and the controls.     

Pharmacologic prophylaxis of allergic rhinitis: Relative efficacy of hydroxyzine and chlorpheniramine

The efficacy of hydroxyzine and chlorpheniramine in preventing exacerbations of ragweed allergic rhinitis was compared in a double-blind, randomized manner. Ninety-five subjects with positive skin tests, a history of two previous symptomatic seasons, and discontinuation of immunotherapy for at least 1 yr received either hydroxyzine 150 mg/day, chlorpheniramine 24 mg/day, or placebo during the 1978 ragweed season. Subjects in the placebo group experienced annoying or disabling sneezing 50% of days during the period of highest pollen counts whereas those in the chlorpheniramine and hydroxyzine groups experienced this symptom with equal severity only 22% and 12% of days, respectively. Suppression of rhinorrhea and itchy nose was similar although less dramatic. Both antihistamines were more effective than placebo in altering conjunctivitis, but neither decreased the frequency or severity of nasal stuffiness. Skin tests to ragweed decreased in diameter during the season by 38%, 13%, and 3% among patients receiving hydroxyzine, chlorpheniramine, and placebo, respectively. Frequent drowsiness occurred initially in subjects taking both antihistamines but did not persist. Thus, prophylactic antihistamine therapy effectively prevents most symptoms of seasonal allergic rhinitis without persistent drowsiness. These data further suggest a therapeutic advantage for hydroxyzine over chlorpheniramine in the doses used.     

Suppression of seasonal allergic rhinitis symptoms with daily hydroxyzine.

The effectiveness of hydroxyzine in the suppression of allergic rhinitis symptoms was evaluated using a double-blind, parallel study design during the 1977 ragweed season. Forty-three subjects with positive ragweed skin tests and a history of an exacerbation of symptoms during August and September of the previous two years were randomly assigned to receive either hydroxyzine or placebo. Subjects scored the severity and duration of symptoms in a daily diary and adverse effects were evaluated from a structured interview at two-week intervals. Although drowsiness and dry mouth were frequent initially among the hydroxyzine-treated patients, these minor side effects rapidly disappeared as the dose was slowly increased, and all but one subject tolerated 150 mg/day. Subsequently, during the period of the highest ragweek pollen counts, the hydroxyzine-treated group spent significantly more days free of symptoms or with only mild sneezing, rhinorrhea, and eye symptoms than subjects who took placebo (p less than 0.05). Thus, hydroxyzine appeared to be well tolerated on a continuous daily basis and was effective in suppressing most of the symptoms of seasonal allergic rhinitis. Comparison of hydroxyzine with antihistamines more traditionally used for allergic rhinitis appears warranted.     

A controlled study of the effectiveness of the Rinkel method of immunotherapy for ragweed pollen hay fever

In a double-blind study, we compared the effects of the Rinkel method of immunotherapy with ragweed pollen extract and placebo on symptoms of ragweed hay fever and immunologic parameters in 24 ragweed-sensitive patients. Each had a skin-test end point by Rinkel serial dilution titration to ragweed pollen extract at 1:312,500 w/v or greater dilution, a 2+ skin test to ragweed AgE at 0.1 μg/ml or greater dilution, and in vitro leukocyte histamine release by ragweed pollen extract. None had had immunotherapy for at least 7 yr. Patients matched on the basis of leukocyte histamine release by ragweed were assigned to two treatment groups (12 patients in each group). One group received ragweed pollen extract, and the other, placebo, both administered by the Rinkel method between June and October, 1978. Treatment doses were derived from skin-test end points. The median maintenance (“optimal dose”) for patients receiving ragweed pollen extract was 0.53 ml of 1:312,500 w/v and the mean cumulative dose of ragweed pollen extract given during the study contained 0.094 μg of ragweed AgE. Symptom-medication scores of all patients rose and fell with ragweed pollen counts. No significant differences were observed in mean daily symptom-medication scores, antiragweed IgG or IgE levels, leukocyte histamine release by ragweed, total IgE levels, or skin-test end-point dilutions with ragweed pollen extract between the group receiving ragweed pollen extract and the group receiving placebo. Despite the absence of specific effect on symptom-medication scores and measured immunologic variates, 10 of the 12 ragweed-treated patients and 10 of the 12 placebo-treated patients were of the opinion that their hay fever symptoms during the ragweed pollen season were less severe in 1978 than in 1977 and that they had been helped by Rinkel method immunotherapy. Under the conditions of the study, Rinkel method immunotherapy with ragweed pollen extract was no more effective than placebo given in an imitation of the Rinkel method.     

Effects of seasonal allergic rhinitis on fatigue levels and mood

OBJECTIVE: Many allergy patients complain of fatigue, moodiness, and dysphoria during their allergy seasons. This study evaluated the effect of symptomatic allergic rhinitis on both fatigue level and mood. METHOD: Symptomatic ragweed allergic rhinitis patients on no medications and healthy control subjects completed the Multi-Dimensional Fatigue Inventory and the Positive Affect-Negative Affect mood rating scales in an in-out-in ragweed season research design. RESULTS: During ragweed seasons, allergic patients reported higher levels of general fatigue and mental fatigue, but not physical fatigue, as well as reduced motivation. Patients described experiencing feelings of greater sadness and reduced pleasurable engagement. Increased anxiety or emotional distress was not reported. CONCLUSIONS: These findings suggest that having allergic reactions to ragweed pollen causes significant fatigue and mood changes in at least a subgroup of patients. Psychoneuroimmunology and medical genetics research suggests that allergic reactions engender biochemical changes that directly affect the central nervous system.     

Nasal secretory antibody to inhalant allergens in allergic and non-allergic patients

Nasal washings were obtained from normal and ragweed allergic (immunized and non-immunized) subjects. All specimens contained `blocking'' antibodies as measured by their ability to inhibit antigen E induced histamine release from human leucocytes. The antibody was largely of the IgA class (secretory antibody). There was little difference between the blocking activity of normal, allergic and immunized allergic subjects. All patients also had blocking secretory antibody against grass pollen group I antigens to which they were not clinically sensitive. There was no correlation between the level of anti-grass and anti-ragweed activity; moreover, no antibody activity was demonstrated against an allergen (pitressin) to which the subjects had not been exposed. A modest but significant rank correlation was found between the level of serum and nasal anti-ragweed activity in the allergic immunized patients, but no relationship obtained between the clinical severity of symptoms referable to ragweed exposure and the level of nasal antibody. It is concluded that all subjects environmentally exposed to pollen allergens develop nasal blocking antibodies; the level of this antibody bears little relationship to parenteral immunization and no detectable relationship to the clinical severity of ragweed hay fever.     

Randomized controlled trial of ragweed allergy immunotherapy tablet efficacy and safety in North American adults

BackgroundRagweed is an important cause of allergic rhinitis with or without conjunctivitis (AR/C) in North America and elsewhere. Allergen immunotherapy enabling safe patient self-administration is considered an unmet clinical need. Allergy immunotherapy tablet (AIT) treatment has shown promising efficacy and safety for grass allergy but has not been assessed for ragweed allergy.ObjectiveTo evaluate efficacy and safety of 2 short ragweed AIT doses in patients with AR/C.MethodsAdults with ragweed pollen–induced AR/C were randomized 1:1:1 to daily ragweed AIT (6 or 12 Amb a 1 units) or placebo before, throughout, and after ragweed season (approximately 52 weeks). Patients could use predefined allergy rescue medications in season. Efficacy end points included peak and entire season total combined score (TCS) and its components daily symptom score (DSS), and daily medication score (DMS). Safety assessments included adverse events.ResultsA total of 565 patients were randomized. During peak season, the 6– and 12–Amb a 1 unit ragweed AIT doses showed 21% (?1.76 score) and 27% (?2.24 score) improvement in TCS vs placebo (P < .05). The 6– and 12–Amb a 1 unit AIT doses significantly improved DSS and DMS vs placebo (P < .05). Peak and entire season efficacy were comparable. The 12–Amb a 1 unit AIT dose reduced peak-season TCS vs placebo by 21% and 25% in subgroups with and without local application-site reactions, respectively. Most treatment-related adverse events were mild, oral reactions; no systemic allergic reactions were reported. One patient in the 6–Amb a 1 unit group received epinephrine at an emergency facility for sensation of localized pharyngeal edema.ConclusionIn this trial, ragweed AIT was effective and well tolerated in ragweed-allergic North American adults.Trial Registrationclinicaltrials.gov Identifier: NCT00783198.     

The reduction of rhinitis symptoms by nasal filters during natural exposure to ragweed and grass pollen

BACKGROUND: Prototype nasal filters were developed to collect inhaled pollen. This study evaluated the efficacy of the filters for prevention of rhinitis symptoms during acute outdoor pollen exposure. METHODS: A randomized double-blind design was used. Subjects (n=46) with a history of autumn exacerbation of rhinitis and positive skin test to ragweed, Bermuda and/or Bahia grass wore either active or placebo nasal filters for 2 h in autumn in a park containing these species. Major and Total Symptoms scores were recorded at 0, 30, 60, 90 and 120 min. RESULTS: Subjects wearing active nasal filters had significantly reduced scores, at all time-points compared with placebo group (all P <0.05). Of 14 individual symptoms measured, seven were significantly reduced (number of sneezes, runny nose, itchy nose, sniffles, itchy throat; itchy eyes and watery eyes) and another three showed a trend towards lower severity. The nasal filters also enabled the resolution of existing symptoms. Maximal difference in symptoms was seen immediately after subjects had spent 20 min sitting beside a large patch of ragweed. CONCLUSION: This is the first clinical trial of a nasal filter. The results suggest it has potential for enhancing rhinitis management during acute allergen exposure.     

Allergen-Induced Synthesis of Interleukin-5, but not of IgE, is a Key Mechanism Linked to Symptomatic Episodes of Seasonal Allergic Rhinitis in Sensitized Individuals

Some individuals with detectable levels of Japanese cedar (Criptomeria japonica) pollen-specific immunoglobulin (Ig)E in serum have no apparent nasal symptoms during the pollen season. The response of CD4⁺ T-helper (Th) cells to the pollen allergen might differ fundamentally between asymptomatic and symptomatic individuals who are already sensitized to the pollen. The aim of this study was to discern the possible differences in responses of peripheral blood mononuclear cells (PBMCs) to the pollen allergen between asymptomatic and symptomatic subjects who have been sensitized to the pollen. This study included 20 non-atopic healthy volunteers (non-atopic group) and 48 patients who had detectable levels of the pollen-specific IgE before the pollen season in 1997. In the review of nasal symptoms during the pollen season 1997, 24 patients had typical symptoms of seasonal allergic rhinitis (symptomatic group), and the remainder had no seasonal aggravation of nasal symptoms (asymptomatic group). Peripheral blood mononuclear cells (1.0 × 10⁷ cells/well) were obtained from each individual during the pollen season and cultured in the absence or presence of 12.5 μg of Cry j 1 for 4 days. The concentrations of IgE, interleukin-5 (IL-5), and interferon-gamma (IFN-γ) in the culture supernatants were measured. The levels of IgE produced by Cry j 1-stimulated PBMCs of the asymptomatic and symptomatic groups were significantly higher than those of the non-atopic group, but did not differ between the asymptomatic and symptomatic groups. The levels of IL-5 produced by Cry j 1-stimulated PBMCs did not differ significantly between the non-atopic group and the asymptomatic group, but the levels of IL-5 were significantly higher in the symptomatic group than in the asymptomatic group as well as the non-atopic group. The levels of IFN-γ produced by Cry j-1 stimulated PBMCs did not differ significantly among the three groups. In conclusion, our study has suggested that Japanese cedar pollen-induced synthesis of IL-5, but not of IgE or IFN-γ, is likely to be a key mechanism linked to the symptomatic episode of seasonal allergic rhinitis in individuals sensitized to the pollen.     

Birch and ragweed pollinosis north of Milan: a model to investigate the effects of exposure to "new" airborne allergens

BACKGROUND: The effects of sudden and massive exposure of the general population to novel airborne allergens are not known. This study aimed to investigate the clinical effects of two "new" allergens, ragweed and birch, in an area north of Milan during the last 15 years. METHODS: We reviewed the records of 2571 monosensitized patients seen during the last 10 years in two allergy units north of Milan. Data included age at onset of allergic symptoms, and family history of allergic diseases. In this sample, 500 were allergic to grass, mite, birch, and ragweed; 293 to pellitory; 167 to mugwort; 100 to Alternaria; and 11 to plantain. RESULTS: Birch pollen-allergic patients and ragweed pollen-allergic patients showed a similar mean age at onset (35.3 years vs. 35.1 years; P = NS), but were significantly older than all other groups of patients (P < 0.001). Patients allergic to ragweed and birch pollen, 304 and 323 respectively, were >30 years at the onset of allergic symptoms. A family history of allergic disorders among first degree relatives was far less frequent among patients allergic to birch pollen (29%) or ragweed pollen (27%) than among patients sensitive to all other airborne allergens, except those allergic to mugwort pollen (P < 0.001). In both ragweed and birch groups, a positive family history was significantly more common among subjects < 30 years than in those > 30 years at onset of respiratory allergy (81/196 (41%) vs. 54/304 (18%), P < 0.001 for the ragweed group; 80/177 [45%]vs. 65/323 (20%), P < 0.001 for the birch group). CONCLUSION: Exposure of the general population of this area to two new airborne allergens resulted in the onset of respiratory allergy in many older people who lacked any relevant predisposing factor. Although we cannot exclude the possibility that those who became allergic had been exposed to birch or ragweed pollen elsewhere, a more likely explanation is a specific susceptibility that remains viable until the subject encounters the "right" allergen.     

Canadian trial of sublingual swallow immunotherapy for ragweed rhinoconjunctivitis.

BACKGROUND: Sublingual swallow immunotherapy has been increasingly recognized as a safe and efficacious alternative to parenteral specific immunotherapy. OBJECTIVE: To determine the safety and efficacy of sublingual swallow immunotherapy ragweed allergen extract for rhinoconjunctivitis treatment starting just before and continuing through the ragweed pollen season. METHODS: This randomized, double-blind, placebo-controlled study was performed in children and adults with a documented history of allergic rhinoconjunctivitis during ragweed season at 9 Canadian allergy centers. Active treatment was standardized extract of ragweed allergen administered as sublingual swallow drops at increasing doses starting shortly before the pollen season and maintenance doses continued daily during the season. Primary efficacy variables were symptom and medication scores, and secondary variables included global evaluation of efficacy and immunologic measurements. RESULTS: Eighty-three patients were included in the safety analysis; 76 patients were included in the intent-to-treat analysis. Nine placebo recipients and 1 treatment recipient withdrew for lack of efficacy (P = .004). Nine patients in the treatment group withdrew because of adverse events, none serious (P = .003). Investigator evaluation of efficacy showed that significantly more patients improved and fewer deteriorated in the treatment group vs the placebo group (P = .047). Ragweed IgE and IgG4 levels increased significantly in treatment recipients vs placebo users (P < .001). Sneezing and nasal pruritus approached significant improvement in the treatment group vs the placebo group (P = .09 and .06, respectively). Quebec City experienced low pollen counts. Excluding Quebec City, significant improvement was seen for these 2 symptoms (P = .04). CONCLUSION: Sublingual swallow immunotherapy seems to be safe and efficacious for ragweed rhinoconjunctivitis even when started immediately before the ragweed pollen season.     

Effect of environmental exposure on bronchial sensitivity to antigen.

Bronchial sensitivity to grass and ragweed extracts was determined in four adult asthmatic subjects at the beginning and end of the grass and ragweed pollen seasons. 4 subjects with ragweed sensitivity had increased bronchial sensitivity to ragweed antigen at the end of the ragweed season. 2 of 3 grass sensitive subjects demonstrated increased bronchial sensitivity to grass antigen after the grass pollen season. This study suggests that natural environmetnal exposure to pollen antigens may induce priming in the lung.     

Influence of natural exposure to pollens and domestic animals on airway responsiveness and inflammation in sensitized non-asthmatic subjects

BACKGROUND: Atopy may be a risk factor in the development of asthma. Indoor allergens are considered to be more potent asthma inducers than outdoor ones such as pollens. Lower airway inflammation may be present in non-asthmatic subjects during natural exposure to relevant allergens and may eventually lead to the development of asthma. AIMS: To document seasonal variation in lower airway responsiveness and inflammation in sensitized non-asthmatic subjects, during natural exposure to allergens, and to determine whether it is more marked in those exposed to animals to which they are sensitized. METHODS: Twenty-two atopic subjects were seen during and out of the pollen season. All (but the controls) were sensitized to domestic animals, and to trees, grasses or ragweed. Eleven were not exposed to animals at home and 8 were exposed. They were compared with 3 normal controls. A respiratory questionnaire was administered, allergy skin prick tests, spirometry, methacholine challenge, blood and induced sputum with differential cell counts were obtained during the pollen season for all subjects. These tests were repeated out of the pollen season. RESULTS: Throughout the study, none of the subjects had asthma symptoms. Mean PC(20) was significantly lower in subjects exposed to animals compared with unexposed subjects or controls, both during and out of the pollen season. In season, subjects exposed to animals had significantly higher sputum eosinophil numbers than unexposed or normal control subjects. CONCLUSIONS: Non-asthmatic atopic subjects show variable degrees of airway responsiveness and inflammation. However, subjects exposed to animals show higher airway eosinophilia, which may suggest they are at increased risk of developing airway hyperresponsiveness and asthma.     

Ragweed allergy immunotherapy tablet MK-3641 (Ragwitek®) for the treatment of allergic rhinitis

ABSTRACT

Introduction: Allergic rhinitis (AR) is among the most common chronic conditions affecting both children and adults. It is the cause of significant morbidity from the symptoms and interference with sleep. It results in major impairment of performance both at school and at work. In the U.S. and certain parts of Europe, ragweed pollen is a major cause of seasonal AR. In 2014, the U.S. Food and Drug Administration (FDA) approved a sublingual ragweed tablet (MK-3641) for use in adults with ragweed-induced AR.

Areas covered: This paper will review the impact of ragweed-induced AR and available treatments including subcutaneous immunotherapy and studies with MK-3641. The principal search method was PubMed.

Expert commentary: One dosing finding, two 28-day safety and two 52-week safety and efficacy studies have been conducted with MK-3641. The 12-U (12μg Amb a 1) tablet was the most effective. Local application site reactions were common but usually not serious. Only one, non-serious systemic reaction was reported in four safety studies. MK-3641 is a safe and effective treatment for ragweed-pollen-induced AR when treatment is initiated ≥ 12 weeks prior to the onset of the ragweed pollen season.     

IgE-mediated allergy to phytase -- a new animal feed additive

BACKGROUND: Although fungal phytase is frequently used as an additive to animal feed few investigations of its allergenic property have been conducted. METHODS: Fifty-three subjects occupationally exposed to powdered phytase from Aspergillus niger were studied. Exposure data and symptoms were registered by the company physician. RESULTS: Thirty-eight subjects complained of work-related respiratory symptoms and 14 of them showed phytase-specific IgE antibodies; only one asymptomatic subject revealed such antibodies. IgE antibodies were significantly more frequently found in the high-exposure group (technical centre) when compared with the low-exposure group (laboratories, experimental animal husbandry). Phytase-specific IgG antibodies were present in 19 symptomatic (50%) and five (33%) asymptomatic subjects. CONCLUSIONS: Our results demonstrate that powdered fungal phytase is a highly sensitizing substance whose inhalation exposure should be avoided. Hypersensitivity symptoms could be prevented by means of extensive hygienic measures and ongoing medical surveillance.     

Controlled trials with four per cent cromolyn spray in seasonal allergic rhinitis*

Thirty-two patients with seasonal allergic rhinitis due to weed pollen were treated beginning prior to the weed pollen season of 1974 with either 4% cromolyn sodium or placebo nasal spray. The patients were followed on treatment with symptom diary cards and bi-weekly physician examinations for a period of 10 weeks. Radioallergosorbent (RAST) titres for the major weeds in the Denver area (ragweed, Russian thistle, and sage) were determined before the weed pollen season, and one and three months after the weed pollen season. There was no significant difference in symptom scores between the 4% cromolyn sodium- and placebo-treated groups, nor objective evidence on bi-weekly examinations by a physician to suggest differences in the two groups. Significant differences in favor of the 4% cromolyn-treated group were noted in the amount of antihistamines taken for symptomatic relief during the weed pollenating season, suggesting some protective effect of the drug. The clinical significance of this finding is not clear. Selecting patients with high baseline RAST titres for one or more of the major weeds did not alter the results of the study. In a second double-blind study twenty-two patients reporting to the allergy clinic with symptomatic seasonal allergic rhinitis due to weeds were randomly assigned to receive 4% cromolyn sodium or placebo nasal spray and followed through the weed pollen season. There was no difference between the two groups in either symptom scores or use of antihistamines for asymptomatic relief.