Minimal persistent inflammation is a physiopathological phenomenon induced by the presence of an anti-inflammatory cell infiltrate together with ICAM –1 expression in the epithelial cells in the absence of clinical symptoms. The second-generation antihistaminies have been shown to exert an anti-inflammatory effect. This effect is greater when the drug is administered continuously. No studies have been specifically designed to clarify the indication of treatment on a continuous basis or upon demand. Second generation antihistaminies were developed for safe treatment of allergic rhinitis and urticaria. They are highly selective for the H1 receptor. Of the second-generation antihistaminies, desloratadine has the highest binding affinity for the receptor. Desloratadine and fexofenadine do not impair psychomotor functioning and are comparable with placebo in terms of somnolence. Nowadays, individualisation of treatment according to the particular characteristics of each patient seems to be the best approach.