Discriminant analysis in allergic rhinitis and asthma: methacholine dose-response slope allows a good differentiation between mild asthma and rhinitis

Total serum immunoglobulin E levels in a case-control study in asthmatic/allergic patients, their family members, and healthy subjects from India

BACKGROUND

Total immunoglobulin E (IgE) is an important indicator of allergic disorders. However, its role in allergic patients in India has not been evaluated in relation to atopic status for a reference range as compared with healthy subjects.

OBJECTIVE

The aim of the study was to establish serum IgE levels in a diseased group, study its relationship with atopy, and to compare the same with healthy volunteers in Indian subjects.

METHODS

Four hundred and eighty asthmatics/allergic patients, 100 first-degree relatives of asthmatics, and 120 unrelated normal healthy volunteers from Delhi region were recruited for the study. Atopy was established by family history and skin test to common indigenous allergens and, total and specific IgE measurements. Statistical analysis was performed with the help of SPSS software program.

RESULTS

The mean IgE levels were the highest in asthmatic patients and the lowest in the control healthy group. IgE was significantly high in the male than the female healthy volunteers (P<0.05), but not in the diseased group. Prosopis juliflora among pollen allergens and Alternaria alternata among fungal allergens were important sensitizers in allergic patients with 34.7% and 17.7% skin positivity, respectively. Atopic status and asthma were found to be the best predictor of IgE, which was highly significant (r(2)=0.239, P<0.00001). However, at 95% confidence interval as many as 50% of asthmatic patients had their IgE values in the normal range.

CONCLUSION

The IgE levels in Indian allergic patients is significantly related to atopy, but due to wide overlap of IgE levels in patients and healthy subjects, its diagnostic significance in Indian population seems to be limited.

Psychologische Aspekte der Allergischen Rhinitis

Zusammenfassung. Theoretischer Hintergrund und Fragestellung: Die allergische Rhinitis ist die häufigste atopische Erkrankung, ihre Prävalenz scheint stetig zuzunehmen. Wie bei anderen chronischen Erkrankungen ist ein Einfluss psychischer Faktoren auf das Krankheitsgeschehen wahrscheinlich. Methode: Die vorliegende Übersichtsarbeit stellt Befunde aus 70 Jahren Forschung zur Psychologie der allergischen Rhinitis zusammen. Diese werden in ein Gliederungsraster integriert, das die Einordnung biopsychosozialer Bedingungsfaktoren erlaubt und die Manifestation auf verschiedenen Verhaltens- und Erlebensebenen berücksichtigt. Ergebnisse und Schlussfolgerungen: Krankheitsverhalten, Laienstörungskonzepte, Neurotizismus und psychophysiologische Stressreaktivität stellen psychologische Aspekte dar, die zur Chronizität der Erkrankung und zur subjektiven Beeinträchtigung beitragen. Es besteht in diesem Bereich noch erheblicher Forschungsbedarf.

Age of onset and the characteristics of asthma

OBJECTIVE

The aim of this study was to evaluate the characteristics of asthma in patients with different ages of disease onset.

METHODOLOGY

Five hundred and four asthmatic patients (303 males and 201 females) were divided into five groups based on age of onset (group I, age of onset < 15 years old; group II, 15-24 years old; group III, 25-44 years old; group IV, 45-64 years old; and group V, > 64 years old). The relationship between age of onset and the characteristics of asthma, including lung function, reversibility, atopic status and the incidence of coexistent allergic rhinitis was assessed. Multivariate analysis, adjusted for the duration of disease, gender, educational level, smoking status, and degree of previous inhaled corticosteroid treatment, was performed.

RESULTS

Thirty per cent of the patients developed asthma before they were 14 years old (group I), and the percentages of those developing asthma at other ages of onset were: group II, 12%; group III, 29%; group IV, 21% and group V, 8%. In all, 57.6% of the asthmatic patients had coexistent allergic rhinitis; younger patients tended to have this comorbidity. The pulmonary function of older onset asthma patients was worse than that of early onset patients. The multivariate analysis showed that there was a positive correlation between the reduction of pulmonary function and duration of the disease (P < 0.001), but there was no relationship between pulmonary function and gender (P = 0.502), educational level (P = 0.734), smoking pack-years (P = 0.902), or degree of use of inhaled corticosteroid treatment (P = 0.586).

CONCLUSION

Asthma is a heterogeneous disease with a wide variety of presentations. This study provides information about the disease characteristics and their relationship with age of onset. Further study is necessary to determine why these differences exist.

Hypertonicity of the challenge solution may increase the diagnostic accuracy of histamine challenge

There is significant overlap in the responsiveness to direct airway challenges, such as the histamine challenge, between asthmatic and non-asthmatic subjects, which decreases their accuracy in the diagnosis of asthma. To minimise this overlap, a new test, hypertonic histamine challenge, was developed. Fifteen healthy subjects, 16 subjects with steroid-naive asthma, and 16 asthmatic subjects undergoing inhaled corticosteroid treatment underwent inhalation challenges with hypertonic saline, isotonic histamine, and hypertonic histamine, using an ultrasonic nebuliser and 2-min tidal breathing method. The increase in histamine solution tonicity decreased the histamine PC20 values only in the steroid-naive asthmatic subjects (1.1 (0.5-2.7) vs. 0.5 (0.2-1.2) mg/ml, P = 0.047). Using 1mg/ml as the cut-off value, the sensitivity, specificity, and accuracy of the hypertonic histamine challenge to detect steroid-naive asthma was 81%, 100%, and 90%. The respective values for the isotonic histamine challenge were 56%, 100%, and 77%. Furthermore, there was a statistically significant difference in the hypertonic histamine PC20 between steroid-naive and steroid-treated asthmatic subjects, which could not be detected in the isotonic histamine PC20. The hypertonic histamine PC20 was highly repeatable, with a single determination 95% range of +/-1.35 doubling concentrations. The hypertonic histamine challenge was safe but provoked more cough and throat irritation than the other two challenges. In conclusion, compared with a conventional, isotonic histamine challenge, hypertonic histamine challenge may be more accurate in the diagnosis of asthma and also, more capable to detect the effects of inhaled corticosteroid treatment.