Atopy in wheezing infants always starts with monosensitization.

Previously, evidence has been provided that sensitization is frequent in asthmatic children and polysensitization represents the natural history of allergy. The aim of this study was to investigate whether polysensitization may occur primarily in infants with wheezing. Thus, 98 infants (<1 year of age) were studied at the onset of wheezing symptoms. All children underwent three visits (each including skin-prick test): at baseline and after 2 and 5 years. At onset of wheezing, approximately 20% of infants were sensitized, whereas at 6 years the percentage was >60%. The most important finding was that there was no polysensitized infant at baseline, whereas most of the sensitized children were polysensitized at 6 years. Moreover, the number of sensitizations increased with age. House-dust mites were the most important cause of allergic symptoms. Wheezing may disappear mainly in nonallergic children. In conclusion, this study provided the first evidence that respiratory allergy always starts with monosensitization and confirms previous studies concerning the natural history of allergy characterized by the progression toward polysensitization.

Allergic children have more numerous and severe respiratory infections than non-allergic children.

Allergic disorders are characterized by Th2-polarization, and hence physiological Th1-dependent mechanisms for fighting respiratory infections (RI) may be defective. This study aimed at evaluating the number and duration of RI in allergic and non-allergic children suffering from recurrent RI. One hundred seventeen children (4.02 +/- 1.0 yr, 72 males and 45 females) were studied during the spring, 46 were allergic. Allergic children showed a significantly higher number (mean 1.26 +/- 0.73) and longer duration of RI (8.92 days) in comparison with non-allergic group (0.94 +/- 1.37 and 4.85 days) (p = 0.0001 and p = 0.009, respectively). In conclusion, this study provides the evidence that allergic children have more numerous and severe RI than non-allergic children.

"Early" cat ownership and the risk of sensitization and allergic rhinitis in Ligurian children with respiratory symptoms.

BACKGROUND: Studies on the role of cat ownership in the development of allergy have lead to conflicting results, probably owing to heterogeneity of the populations evaluated. OBJECTIVE: To evaluate the possible effect of cat ownership on the frequency of sensitization and asthma or rhinitis in children living in Liguria, Italy, who attended a pediatric clinic for respiratory symptoms. METHODS: We enrolled 269 consecutive school-aged children in 12 months. Sensitization to aeroallergens by skin prick testing and the presence of respiratory symptoms (ie, asthma and rhinitis) were evaluated. To analyze the role of different independent variables in association with respiratory symptoms and sensitization, a multiple logistic regression analysis was performed. RESULTS: Of 269 children, 81 were exposed to cats at home in the first 2 years of life ("early" cat owners), 65 after the first 2 years of life ("late" cat owners), and 123 never ("never" cat owners). Early cat ownership was significantly associated with a lower risk of cat sensitization compared with never cat ownership (adjusted odds ratio [ORadj], 0.32; 95% confidence interval [CI], 0.14-0.74; P = .01). Early cat ownership was also associated with a significantly lower risk of allergic rhinitis than late cat ownership (ORadj, 0.43; 95% CI, 0.22-0.85) or never cat ownership (ORadj, 0.51; 95% CI, 0.28-0.92). No differences in the frequency of asthma were found among the 3 groups (P = .74) CONCLUSIONS: Cat ownership in early childhood can play an important role in preventing sensitization to cat and in lowering the frequency of allergic rhinitis, at least in children with the characteristics of the population studied.

The natural history of allergy: the development of new sensitizations in asthmatic children.

Allergy is an important risk factor for asthma in children as most of asthmatic children are sensitized. The aim of the study was to investigate the natural course of sensitizations in a group of children (340) at the onset of asthmatic symptoms. We subdivided children in three groups depending on the age at first visit (3-7-11 years) and followed them for 4 years. All children underwent three visits, each including skin prick test, every two years. In the 3-year age group (n = 133), 59% of children were sensitized at first visit, but the percentage increase to 88% at third visit. When looking only at allergic children at first visit (261), we demonstrated that polysensitization became higher than monosensitization since the age of 11. Analysis of sensitization distribution over the time revealed that house dust mites were prominent from the age of 3 years. Parietaria and grass pollens as well as olive pollen significantly increased, particularly during the 4-year follow-up in the 7-year group. Analysis of sensitization score demonstrated that the age range from 3 to 11 is at high risk to polysensitization. In conclusion, this study provides evidence that sensitization is frequent in asthmatic children, polysensitization represents the natural history of allergy and the type of immune response should appear different for each allergen.