[The relation between rhinitis and allergic asthma. The action of antihistaminics on bronchial hyperreactivity]

The connections which maintain rhinitis and allergic asthma are less simple than it appears. If there is an indisputable relationship between rhinitis and asthma it is far from systematic. Several factors regulate this relationship. The sensitivity towards perennial allergens is more readily associated with asthma or non-specific bronchial hyper-reactivity than the sensitisation to seasonal allergens while both are connected to rhinitis. Several explanations can be touched upon: the size of the allergen dose, the duration of exposure, and polysensitisation. On the other hand the risk of developing asthma is much greater if there is an increase in the total IgE level. Finally the intensity of nasal inflammation may itself alter the intensity of the bronchial hyperreactivity. In spite of these connections and the efficacy of the recent anti-histamines on rhinitis, the known effects of anti-histamines on the bronchi remain marginal.