A link between skin and airways regarding sensitivity to fragrance products?

BACKGROUND

Exposure to volatile fragrances is commonplace and may be related to various eye and airway symptoms. Skin exposure to fragrances is known to cause perfume contact allergy and eczema, but it is unknown whether eye or airway symptoms elicited by fragrance products are associated with contact allergy or eczema.

OBJECTIVES

To investigate if eye and airway symptoms elicited by fragrance products are associated with perfume contact allergy or hand eczema in a population-based sample.

METHODS

A questionnaire on eye and airway symptoms elicited by fragrance products was mailed to 1189 individuals who had recently participated in a Danish population-based study of allergic diseases. Results from the questionnaire about localization and character of the symptoms were compared with data on patch testing and 1-year prevalence of hand eczema collected during the health examination.

RESULTS

Positive, independent and significant (P < 0.05) associations were found between eye and airway symptoms elicited by fragrance products and perfume contact allergy (adjusted odds ratios 2.0-3.7) and hand eczema (adjusted odds ratios 1.6-2.6). In further analysis, similar and consistent results were found regarding severity of the symptoms. No associations were found between nickel contact allergy and the symptoms. Female sex and psychological vulnerability were independently associated with eye and airway symptoms elicited by fragrance products, but adjustment in multivariate analysis did not change the results regarding perfume contact allergy and hand eczema.

CONCLUSIONS

Individuals with perfume contact allergy and/or hand eczema, as opposed to those without, have more frequent and more severe eye or airway symptoms after exposure to volatile fragrance products. Having hand eczema has the greatest impact on reporting eye and airway symptoms elicited by fragrance products.

House dust mites and their allergens at selected locations in the homes of house dust mite-allergic patients

BACKGROUND

Knowledge of the occurrence of house dust mites (HDM) and their allergens in domestic locations is important when planning intervention.

OBJECTIVE

The aim of this study was to describe the distribution of HDMs and their allergens before intervention in multiple locations in the homes of newly diagnosed HDM-allergic patients with a known high Der 1 concentration in their mattress dust.

METHODS

Dust was collected from ten locations in the homes of eight HDM-allergic patients. Dust was analysed for allergen content with ELISAs for Der f 1, Der p 1 and Der m 1; and HDM were counted. Total allergen concentrations ( micro g Der 1/g dust) were expressed as the sum of Der f 1, Der p 1 and Der m 1.

RESULTS

On mattresses the median concentration was 86 micro g Der 1/g dust (range 30-288) and 188 mites/g dust (range 12-1910). Der 1 exceeded 10 micro g/g dust in mattresses (8/8), duvets/pillows (3/8), a bedroom carpet (1/1), a living room carpet (1/6), upholstered furniture (2/8) and a curtain (1/5). Uncarpeted floors, upholstered furniture, bookshelves and walls had significantly lower Der 1 concentration than the mattresses. The relative contribution of Der p 1, Der f 1 or Der m 1 to Der 1 was related to homes, rather than to the location. Der m 1 only occurred in minute amounts.

CONCLUSION

For HDM intervention, our results indicate that priority should be given to the removal of allergens from mattresses, and in addition from carpets, duvets/pillows and upholstered furniture. Dust from walls, uncarpeted floors, bookshelves and curtains appear to contribute insignificantly to the domestic HDM allergen load.

Side-effects of insect venom immunotherapy: results from an EAACI multicenter study. European Academy of Allergology and Clinical Immunology

BACKGROUND

The effect of venom immunotherapy (VIT) is well documented, but fear of systemic side-effects (SE) may prevent its use. The study aimed to analyze the character and frequency of SE and risk factors.

METHODS

In a prospective study, 19 European centers included patients starting on VIT for systemic reactions to insect stings. Various dose regimens were applied.

RESULTS

Data from 840 patients with a total of 26 601 injections were obtained. Seventy-one percent were treated with Vespula-venom extract and 27% with honeybee-venom extract. Twenty percent of patients had SE corresponding to 1.9% of injections during dose increase and 0.5% during the maintenance phase. The vast majority of the 280 reactions were mild: only one-third required medical treatment. Injected or inhaled adrenaline was applied in six patients, of whom only one had a drop in blood pressure and collapse. Female sex, bee-venom extract, and rapid dose increase, but not severity of insect sting reactions, increased the risk of SE. The severity of SE was less in males but was not related to age, treatment phase, species of insect, or severity of insect sting reactions.

CONCLUSIONS

The frequency of SE was low, and the majority of these could be managed without treatment. Risk was increased in females, in bee-venom-treated patients, and in those with rapid dose increase.

Allergen-specific immunotherapy in birch- and grass-pollen-allergic rhinitis. II. Side-effects

BACKGROUND

Allergen-specific immunotherapy (IT) involves the risk of side-effects. Different side-effect profiles have been reported for different allergens, and it would be of great benefit to be able more precisely to predict patient- and allergen-related risk factors.

METHODS

Fifty-two patients with rhinoconjunctivitis and allergy to birch as well as grass pollen participated in a 3-year IT study, with a baseline year followed by 2 years of treatment. During the first treatment year, the patients received double-blinded IT with either birch (Betula verrucosa) or grass (Phleum pratense) pollen extracts adsorbed to aluminum hydroxide. The following year, the other allergen extract was added. Assessment of systemic reactions (SRs) was performed, and related to patient pretreatment parameters such as seasonal symptoms and medication requirement, skin prick test (SPT), conjunctival provocation test (CPT), nasal provocation test (NPT), total and specific IgE, basophil histamine release (HR), eosinophil count (EOS), eosinophil cationic protein (ECP), and eosinophil protein X (EPX).

RESULTS

In total, 44 and 47 patients started IT with birch- and grass-pollen extracts, respectively. All SRs occurred during the dose-increase phase. No life-threatening SRs were observed. There were a higher number of patients with SRs during IT with grass pollen than IT with birch pollen, 21 vs five patients (P<0.001), with SRs to 3.3% of grass-pollen injections compared to 0.7% of birch-pollen injections (P<0.0001). The SRs of birch-pollen IT were mild, consisting of rhinoconjunctivitis and oral-pharyngeal itching, whereas asthma and urticaria episodes were observed in the grass-pollen IT. No difference was found in sensitivity to birch and grass, when measured by SPT, CPT, NPT, specific IgE, or HR, and no difference was found in age, duration of allergic symptoms, prevalence of asthma, mean seasonal birch/grass symptom score, eye-drop use, or antihistamine or prednisolone intake between the group with and without subsequent SRs to IT. No difference was found in EOS, serum ECP, or EPX, between the group with and without subsequent SRs to IT.

CONCLUSIONS

IT with grass-pollen extract seems to be associated with a higher number and more severe SRs than birch-pollen IT. Neither demographic data nor diagnostic tests of allergy such as specific IgE, HR, SPT, CPT, and NPT could identify the patients with subsequent SRs.

Allergen-specific immunotherapy in birch- and grass-pollen-allergic rhinitis. I. Efficacy estimated by a model reducing the bias of annual differences in pollen counts

BACKGROUND

Evaluation of the efficacy of allergen-specific immunotherapy (IT) with pollen extracts is complicated by annual variation in pollen intensity. Our study aimed to evaluate the efficacy of birch and grass IT, taking into consideration these variations.

METHODS

After 1 year of observation, 52 patients with rhinoconjunctivitis and allergy to birch as well as grass pollen were allocated to double-blinded clustered IT with aluminum-adsorbed extract produced from either birch (Betula verrucosa) pollen or grass (PIleum pratense) pollen. After 1 year of treatment, the patients continued IT with their original extract and also received the other extract. During the three consecutive pollen seasons, the rhinoconjunctivitis symptom score and the use of antihistamines, eye-drops, and oral prednisolone were recorded. Longitudinal data analysis was used to investigate the relation between different pollen counts and the magnitude of clinical efficacy.

RESULTS

An effect of IT was found on symptom score, antihistamine intake, and eye-drop use for both birch and grass (P values <0.05). The mean reduction in symptom score/medication by IT ranged from 24% to 95%, depending on mean seasonal pollen counts. A minimum mean seasonal grass-pollen count of 20-30 pollen grains m3 was required for the efficacy of grass IT to emerge.

CONCLUSIONS

A model was developed for evaluation of efficacy in longitudinal IT studies, taking the differences in annual pollen counts into consideration. The model showed a significant beneficial role of pollen IT in rhinoconjunctivitis patients allergic to birch and grass pollen.

Effect of two different types of vacuum cleaners on airborne Fel d 1 levels

BACKGROUND

Vacuum cleaners may increase the level of airborne allergens by leakage through the cleaners or by disturbance of floor dust by the exhaust air produced.

OBJECTIVE

The aim of this study was to evaluate the short-term effect of vacuum cleaning with two different types of cleaners on airborne cat allergen analyzed by a biologic and by an immunochemical test.

METHODS

Ten homes with cats were cleaned in random order with a 1-week interval by a traditional canister type vacuum cleaner (T) and a semi-stationary vacuum cleaner (S) that conducts the air to the exterior through a valve in the wall. Airborne particles were collected by air sampling for 2 hours and cat allergen, Fel d 1, was quantified biologically by basophil histamine release test (HR test) and immunochemically by enzyme linked immunosorbent assay (ELISA).

RESULTS

Using the S resulted in smaller amounts of airborne cat allergen than the T (mean 2.1 ng/m3 air (range .8 to 12.5) versus 5.2 ng/m3 (1.3 to 13.3), P < .002 measured by ELISA). Results from ELISA and HR test correlated well (r = .91, P < .001).

CONCLUSIONS

The use of S with exhaust to the outside of the dwelling gave rise to less airborne low particle size allergen during the cleaning procedure than a T method. The basophil histamine release test could be a valid alternative method to establish allergen content in environmental samples especially in allergen systems with no available monoclonal antibodies.

[Allergy to dust mites]

House dust mites are the most important indoor allergens in our region. During recent years more dwellings have become infested, most likely as a result of increased indoor humidity due to reduced ventilation. Among Danish adults, 14% have developed IgE against mites. The allergens are stable and can remain for years. Keeping the humidity low (< 45%) during winter months is the most important limiting factor for mite growth. It can be accomplished by ventilation and heating. If bedding, pillow, eiderdown and covering mattress are washedat temperatures > 55 degrees C mites are killed and allergens removed. In addition mattress covers seem to be useful, although guidelines for quality assessment are lacking. Reduction in mite exposure will reduce development of allergy in all age groups especially in the newborn period. Immunotherapy can be offered in rhinitis and moderate asthma when sufficient allergen reduction cannot be accomplished.

[House dust mite allergens and mite allergy in Copenhagen dwellings. A cross-sectional study]

The aim of the study was to investigate the influence of various environmental factors on occurrence of house dust mite allergens and the influence of allergen exposure on mite allergy. Ninety-two persons from a population study filled in a questionnaire, were skin prick and lung function tested and dust samples were collected from their mattresses for analyses. Two out of five patients with asthma had a positive skin reaction to house dust mite allergen in contrast to five out of 87 non-asthmatics. Fifty-nine per cent of the dust samples contained (group 1) mite allergen > 2 micrograms/g dust. Such mattresses were older (median 7 years, range 1-22) than mattresses with less allergen (median 4 years, range 1-20). In the six bedrooms reported to be humid or mouldy, mattresses contained high concentration of mite allergens. No other parameter investigated could predict the allergen contents. In almost all cases dust analyses are crucial to be able to advise patients with house dust mite allergy.

Skin symptoms in patients with atopic dermatitis using enzyme-containing detergents. A placebo-controlled study

Detergent enzymes may cause skin irritation and occasionally hypersensitivity reactions. The potential hazards of these enzymes have led some physicians to advise atopic dermatitis patients against the use of enzyme-enriched detergents. A three-phased randomised, double-blind, cross-over experiment was designed to question this recommendation. Each period was of 1 month's duration. In the first phase patients continued using their normal washing detergent. In phase II patients used trial detergent with or without added enzymes, and during phase III patients were given the opposite trial detergent. A total of 25 patients completed the study. The primary efficacy parameters were inter-period changes in corticosteroid usage and changes in SCORAD. Secondary efficacy parameters were altered subjective symptoms scored during the final 2 weeks of each interval. Analyses of all data revealed no statistical differences in any of the primary or secondary parameters comparing treatment and placebo periods. Our data therefore seem to exclude that atopic dermatitis may exacerbate during 1 month's exposure to enzyme-enriched detergents. Since no significant irritant capacity was detected in atopic dermatitis patients, it is unlikely that consumers with "normal skin" will experience any skin discomfort when enzyme-enriched detergents are used.

Exposure chamber for allergen challenge. A placebo-controlled, double-blind trial in house-dust-mite asthma

Exposure chambers have proven to be valuable tools in the study of reactions to aeroallergens, and in monitoring the efficacy of antiallergic therapy. In the present study, 15 house-dust-mite-allergic asthmatics and five nonallergic volunteers were challenged in a recently developed exposure chamber. The trial was performed double-blinded with house-dust-mite allergen or placebo. Patients with allergy to house-dust mite (Dermatophagoides pteronyssinus) (Der p) were included by positive skin prick test, allergen-specific IgE, and conventional bronchial allergen challenge, with nebulizer and mouthpiece. In the exposure chamber, a total allergen dose corresponding to 1200 ng Der p 1 was applied. All participants kept diaries, recording peak expiratory flow rates, symptoms, and medication in periods of at least 2 weeks before and after each challenge. Twelve of the 15 asthmatics reacted with asthmatic symptoms with a median change in FEV1 of -16.4% when exposed to the allergen, but not to placebo, in the exposure chamber. Three patients had only minor symptoms during both chamber exposures and experienced no impairment of pulmonary function. Late-phase reactions were less frequent (one vs three) after the exposure chamber challenges, as compared to the traditional challenges. None of the healthy subjects reacted to the challenges. In conclusion, our exposure chamber was able to elicit symptoms in allergic subjects, and this ability was obtained with only minor amounts of house-dust-mite allergen. The described method could prove to be a more physiologically relevant model to monitor individual responses to aeroallergens.

Antihistamine premedication in specific cluster immunotherapy: a double-blind, placebo-controlled study

BACKGROUND

Specific immunotherapy treatment in allergic diseases involves a risk of systemic side effects. A double-blind, placebo-controlled study was performed in 45 patients allergic to pollen to determine whether pretreatment with loratadine could reduce the number and severity of systemic reactions during the dose-increase phase of cluster immunotherapy.

METHODS

The patients received cluster immunotherapy with a standardized birch (Betula verrucosa) or grass (Phleum pratense) pollen extract adsorbed to aluminum hydroxide. The immunotherapy schedule involved seven visits and 14 injections to reach a maintenance dose of 100,000 standardized quality units. Loratadine, 10 mg, or placebo tablets were administered 2 hours before the first injection at each visit.

RESULTS

A total of 720 injections were given (309 injections in 21 patients receiving loratadine and 411 injections in 24 patients receiving placebo). The median numbers of injections to reach maintenance dose were 15 (range, 14 to 18) in the loratadine group and 16 (range, 14 to 23) in the placebo group (p = 0.037). The numbers of patients with systemic reactions were seven (33%) and 19 (79%) in the loratadine and placebo groups, respectively (p = 0.002). Twenty-five reductions caused by systemic reactions were observed in the placebo group in contrast to nine in the loratadine group (p = 0.047). No life-threatening systemic reactions were observed in either group. Systemic reactions were, however, more severe in the placebo group, mainly because of a significantly higher incidence of urticaria (10 vs 1, p = 0.022).

CONCLUSION

Pretreatment with loratadine seems to reduce both the number and severity of systemic reactions in specific cluster immunotherapy.

Allergen-induced histamine release in intact human skin in vivo assessed by skin microdialysis technique: characterization of factors influencing histamine releasability

BACKGROUND

The purposes of the study were to characterize allergen-induced histamine release in intact human skin in vivo by using a novel microdialysis technique and to study covariates influencing histamine releasability.

METHODS

Hollow microdialysis fibers were inserted into the upper dermis in 15 timothy-sensitivity subjects. Up to 12 fibers were inserted in each subject. Each fiber was perfused with Krebs-Ringer's solution at a rate of 3.0 microliters/min. Three to four serial dilutions of allergen were applied to the skin by intracutaneous injections or skin prick test above individual fibers. Samples were collected in two 2-minute fractions before skin challenge and in 10 consecutive samples for 20 minutes after skin challenge. Histamine was assayed spectrofluorometrically.

RESULTS

A significant dose-response relationship for histamine release was demonstrated with intracutaneous tests and skin prick tests. The time to reach peak histamine release after an intracutaneous test was 4 to 8 minutes, compared with 12 to 14 minutes for a skin prick test. Histamine release correlated significantly with wheal size. Intrasubject coefficient of variation on histamine release was about 20%. A substantial intersubject variation in histamine releasability was observed. Seventy to seventy-five percent of the variation could be accounted for by a combination of gender, total and allergen-specific IgE, and an in vitro basophil histamine release test.

CONCLUSIONS

Using a skin microdialysis technique, we have described in detail histamine release in intact human skin by allergen. The microdialysis method proved to be a reproducible technique for monitoring histamine release in allergic skin reactions and for studying histamine releasability of skin mast cells in vivo.

Exposure chamber for allergen challenge. The development and validation of a new concept

Exposure chambers have proven to be valuable tools in studying allergic diseases. The chamber provides a controlled environment and maintains conditions for measuring the amount of allergen inducing symptoms in allergic subjects. The aim of the present study was to develop and test an exposure chamber. The chamber was constructed as an airtight tent, made of transparent polyethylene, easy to adapt to the shape of an existing room, easy to clean, and providing exact allergen-dosage control. Airflow to the interior of the tent was controlled by a variable inlet ventilator fitted with a micropore filter and balanced by a variable high-volume air-sampler on the outlet side. Trace material and allergen were administered as aerosols with a nebulizer connected to the inlet pipe. Samples were obtained from interior surfaces and filters at the outlet. Two different methods were used to test the concept. One method used a colored, neutral trace substance (phenol red indicator) measured photometrically on extracts from filters. Secondly, house-dust mite allergen (Dermatophagoides pteronyssinus) was applied, with samples analyzed by an ELISA technique. The results demonstrated the ability of the system to administer and sample allergen with a high degree of reproducibility. A clinical pilot trial proved the capability of the system to initiate symptoms in allergic subjects.

[Diagnosis of allergy in bee-keepers. A 1-year prospective study]

Thirty-six Danish bee-keepers were clinically investigated by means of a questionnaire before and after the bee season 1990. Their serum was assayed for IgE and IgG antibody reacting with bee venom, and skin prick tests were performed prior to the season. Thirty-six percent had previously reacted abnormally, either with a systemic reaction (SR) (25%) or a large local reaction (LLR) (11%). Retrospectively, eight of the nine bee-keepers with SR had upon re-exposure developed a normal reaction, in spite of the fact that seven of them had specific IgE and/or a positive prick test at subsequent examination. At follow up 38% of the persons who had previously had a SR reacted with a SR or a LLR on the first sting in the season. Two of eight with previous SR reacted with SR during the observation period in spite of a negative prick test and no specific IgE. Of the bee-keepers who had previously only reacted normally there were no systemic of large localised reactions during the observed period, although six showed signs of IgE-sensitization. The results confirm the problems of identifying patients where immunotherapy is superfluous in the group with previous SR and IgE sensitization.

Histamine-releasing serum factors as a predictor of the outcome of insect sting reactions. Results from a multicentre study

Cord blood cells were incubated (passively sensitized) with sera from 27 patients with previous systemic reactions to insect stings. Histamine release (HR) from these cells was measured following exposure to venom extracts at increasing concentrations. The aim was to see whether this parameter could predict more efficiently than RAST and skin test the outcome of a subsequent re-sting. Results showed that HR from passively sensitized cells tended to reflect skin sensitivity and specific IgE levels. If patients were not re-stung during the follow-up period, HR from the passively sensitized cells frequently decreased whereas an increase was seen (in 6/13) when using sera collected after re-sting. In conclusion HR from passively sensitized cord blood cells could not satisfactorily predict re-sting reactions in the serum donors.

Airway calibre as a confounder in interpreting bronchial responsiveness in asthma

BACKGROUND

The relation between airway responsiveness to constrictor agents and forced expiratory volume in one second (FEV1) is important when interpreting change in airway responsiveness after an intervention. The aim of the study was to analyse the relation between FEV1 as a percentage of predicted values (% predicted) and airway responsiveness between and within asthmatic subjects.

METHODS

Results of non-specific bronchial challenge tests were pooled from two randomised crossover studies comparing the effect of a non-sedative antihistamine with placebo in 35 patients with moderate asthma. The design of the two studies was similar: the provocative concentration of either histamine (first study) or methacholine (second study) resulting in a 20% decrease in ventilatory capacity (PC20) was repeated at two week intervals while patients were treated with the antihistamine or placebo. The dose of inhaled corticosteroid was gradually reduced during the study. Data were analysed with PC20 as the dependent variable in a general linear model so that the influence on PC20 of inhaled corticosteroid dose, antihistamine, and choice of bronchoconstricting agent could be separated from the influence of FEV1% predicted.

RESULTS

The correlation coefficient between mean PC20 and mean prechallenge FEV1 for each patient was 0.45. In the general linear model two thirds (65%) of the variation in PC20 was due to variation between subjects. One third of the within subject variation in PC20 could be explained by variation in prechallenge FEV1% predicted (a change in FEV1 of 27% predicted was associated with one doubling or halving of PC20). Treatment with the antihistamine had no influence on PC20, except when histamine was used as the bronchoconstricting agent. The dose of inhaled corticosteroid had a small but significant effect.

CONCLUSIONS

The variation in a patient's PC20 over time (several months) is related to changes in FEV1% predicted. Variation in FEV1% predicted explains less of the variation in bronchial responsiveness between subjects where a patient specific factor, which is probably related to the pathogenesis of bronchial asthma, seems to dominate.