Reliability of respiratory symptoms to diagnose atopy.

As reliance of responses to epidemiological questionnaires on atopic symptoms is doubtful, we studied the predictive value of these questions relative to atopy, defined by the presence of serum specific IgE, taking into account some extraneous variables such as age and sex. The study population included 2067 adults, 20-60 years old. The protocol consisted of a standardized questionnaire and an evaluation of serum specific IgE using the Phadiatop (Pharmacia Diagnostics, Uppsala, Sweden) test. The predictive value of each symptom suggestive of atopy was quite low, but was much dependent on age and sex. Women more often than men reported atopic symptoms in the absence of atopy. Similarly, the predictive value of each symptom decreased with age. Thus atopic symptoms do not have the same value as predictors of atopy. These findings have both clinical and epidemiological important implications.

Medication requirements and house dust mite exposure in mite-sensitive asthmatics.

To better understand the clinical consequences of exposure to house dust mites (HDM), we investigated the relationship between treatment requirements to control symptoms in mite-allergic asthmatic patients and HDM-allergenic levels in their mattresses. This study included 49 asthmatic subjects recruited from an outpatient clinic. The protocol consisted of a questionnaire about the number of asthma attacks and treatment requirements in the last 3 months. Patients provided a sample of house dust collected from their mattresses by a standardized vacuum cleaning procedure. Mean antigen P1 equivalent defined as the sum of major allergens Der pI and Der fI (Ag P1 Eq) level was 1.34 micrograms/g dust in patients who had no treatment, 5.4 micrograms/g dust in patients who took puffs of beta 2-agonists only when required and 17.8 micrograms/g dust in patients who required daily long-term treatment. Similar relationships were demonstrated between mean Ag P1 Eq levels and the number of asthma attacks. These data support the clinical role of allergenic exposure in HDM-allergic asthmatics.

Altitude and allergy to house-dust mites. A paradigm of the influence of environmental exposure on allergic sensitization.

To further investigate the possibility of a cause and effect relationship between exposure to house-dust mite (HDM) allergens and respiratory disease associated with dust mite sensitivity, we compared schoolchildren living in the Alps, where exposure to HDM is low, with those living at sea level, where it is high. The study included 933 schoolchildren from the fourth and fifth grades. The protocol included the standardized 1978 American Thoracic Society (ATS) questionnaire for children, skin testing using common aero-allergens and controls, and antigenic measurements of dust samples from mattresses (Group I antigen). The prevalence of asthma with positive skin test to HDM and the overall prevalence of positive skin test to HDM were significantly lower in mountain schoolchildren. The mean geometric HDM antigenic level in mattresses was much lower in the Alps (0.36 micrograms/g dust) than at sea level (15.8 micrograms/g dust). In contrast, the prevalence of hay fever and positive skin test to grass pollens as well as the overall prevalence of positive skin tests to grass pollens were significantly higher in the Alps. These data illustrate a striking relationship between exposure to environmental allergens and atopic sensitization.

Atopy and systemic reactions to drugs.

To elucidate whether systemic reactions (SR) to drugs should be included in the atopic status in epidemiological studies, we compared the distribution of atopy in subjects with or without a history of SR to drugs. The studied population comprised 2067 adults, 20 to 60 years old, visiting a health care center for a check-up examination. The protocol included a questionnaire related to history of SR to drugs and a Phadiatop test which evaluates on a blood sample the presence of specific IgE against common aeroallergens. Overall, 14.7% of the study group, including 66% women, reported reliable histories of SR to drugs. The cumulative prevalence of asthma, hay fever and childhood dermatitis was higher in the SR group. By contrast, the percentage of positive Phadiatop tests was similar in subjects with or without a history of SR. Thus atopy, defined by an objective criterion, i.e. the presence of specific IgE against common aero-allergens, is not associated with the occurrence of SR to drugs. Such a history should not be included as part of the atopic status.

Prevalence of allergy to Hymenoptera stings.

In this study, we evaluated the prevalence of systemic reactions to hymenoptera stings in an adult general population, 20-60 years old. The protocol included a standardized questionnaire, skin tests to venom in subjects reporting a history of systemic reaction, and in subjects reporting a history of severe local and systemic reactions, as well as in a control group, a radioallergosorbent test (RAST) to hymenoptera venoms. According to the questionnaire, 1.2% of the study population had a history of systemic reactions. Only 0.85% had both such a history and a positive skin test to venoms. RASTs were positive, for at least one venom, in 57% of subjects with a history of systemic reaction, 15.8% of subjects with a history of severe local reactions, and 6.0% of the control group. In conclusion, this study shows that systemic reactions are not uncommon in the general population. RASTs tests are not sensitive or specific enough to be considered, per se, for indications of allergy to venoms.

[Allergy to Hymenoptera. Incidence and degree of public knowledge]. / Allergie aux hyménoptères. Fréquence et degré d'information du public.

The prevalence of systemic reactions to hymenoptera stings in adults is unknown. To elucidate this point we interviewed 2.067 persons aged from 20 to 60 years who attended a medical screening centre. We asked them whether they had ever experienced a reaction this kind, what they knew about it and what they did, and we performed skin tests to hymenoptera venoms in those who gave a positive answer. The proportion of subjects who had had at least one type of systemic reaction after being stung was 1.2 per cent; 0.9 per cent of the subjects had both a history of reaction and a positive skin test. This figure is in keeping with those obtained in surveys carried out among children, but is does not tally with the mortality figures which probably are grossly under-estimated. The general population is not adequately informed of possible systemic reactions to hymenoptera stings, so that people often fail to consult, and the practitioners themselves do not advise their patients to see an allergologist for evaluation. Thus, adequate information of the general population and the physicians is badly needed.