Prevention of Asthma With Levocetirizine 18 Month Treatment in Infants (12 - 24 Months) Suffering From Eczema (Atopic Dermatitis) and Sensitized to Grass Pollen and/or House Dust Mite (HDM)

Inclusion Criteria: Inclusion criteria which must be verified during screening visit (V1): * Children of either sex aged between 12 and 24 months * Subjects suffering from symptoms of Atopic Dermatitis (AD) lasting cumulatively for at least 2 months since birth * Modified Severity Scoring of Atopic Dermatitis (SCORAD) Index \>= 10 * Subjects whose biological mother or father, or one sibling has a well-documented history of atopy (AD, allergic rhinitis or asthma) Inclusion criteria which must be verified during randomization (V2): * Results of the Radio-allergosorbant (RAST) test for grass pollen (GP) and house dust mite (HDM) are available and Immunoglobulin E (IgE) level against GP \>= 0.35 kUA/l and/or IgE level against HDM ≥ 0.35 kUA/l * Safety laboratory results are within the normal range of the central laboratory or considered as not clinically significant or study disease related by the Investigator Exclusion Criteria: Exclusion criteria to verify at screening visit (V1): Are to be excluded from the participation in the study, those children who * Have height or weight below the 5th percentile * Have experienced at least one episode of wheezing when aged 6 months or over * Have suffered at age 6 months or over, from at least one nocturnal cough episode consisting of 3 (or more) consecutive nights resulting in sleep disturbances in a clinical setting where asthma is likely and other conditions have been excluded * Have chronic pulmonary diseases of any type, such as, but not limited to, cystic fibrosis, or any cranio-facial abnormality, e.g., cleft palate * Have a personal history of sleep apnea or who have siblings with a history of sleep apnea * Are treated with any immunomodulator medication such as, e.g., cyclosporin, cyclophosphamide or FK 506 (Tacrolimus) * Have received or are receiving allergen - specific immunotherapy * Suffer from concomitant dermatological disease/condition other than atopic dermatitis, that might interfere with the evaluation of the clinical response for atopic dermatitis * Have an insufficient wash-out period for the following medications: * Intranasal or systemic antihistamines: 3 days, * Intranasal or systemic decongestants: 3 days, * Loratadine, Desloratadine: 10 days, * Chromones: 2 weeks, * Oral corticosteroids: 1 month, * Chronic use (i.e. cumulatively up to 2 weeks within the last 3 months) of inhaled/intranasal corticosteroids: 1 month, * Ketotifen: 1 month, * Astemizole: 6 weeks * Have been treated with any antihistamine, including ketotifen, with daily intake for more than 2 consecutive months in the last 6 months before screening Subject Exclusion criteria to verify at randomization visit (V2): • Intake of any prohibited medication listed above during the selection period