In 2001-2002, a longitudinal study on the risk of atopic sensitization in children was conducted by the Pneumo-Allergology and Pediatrics departments of the CHU Saint-Pierre Hospital and at the Neonatology Department of the Queen Fabiola Children's University Hospital (HUDERF). The aim of the study was to study bacteria and endotoxins in airborne dust in Brussels homes in order to evaluate their impact on the development of allergic diseases in newborns.

Between December 2000 and August 2002, 114 children (67 from HUDERF and 47 from CHU St-Pierre) were included in the study. These were eutrophic children without acquired pathology or known genetics.

Simultaneously a microbial habitat assessment was performed based on a detailed description and on endotoxin assays in the airborne and deposited dust (mainly mattress).These data can be used to define habitats with high or low contamination.Samples for microbial analyzes (Gram positive and negative and mold) were also carried out.

Preliminary results suggested:

1. A protective effect of airborne dust endotoxins on the risk of developing atopic dermatitis in children at 6 and 12 months of life,
2. An effect of endotoxins promoting the occurrence of wheezing in children after 6 months.

In this current, new study, the investigators will recontact the children who were included in the 2003 study. The goal is to evaluate them clinically and allergically and associate the risk of sensitization / allergic diseases with the microbial exposure of the habitat, measured during the neonatal period.

Siblings and parents who were exposed during the same period will also be evaluated.

Inclusion Criteria:

Children who participated in the study conducted in 2001-2002, their parents and the siblings who were exposed to the same environment at this period.

Exclusion Criteria:

None

Children who participated in the study conducted in 2001-2002, their parents and the siblings who were exposed to the same environment at this period.