Hay fever

In hay fever the allergen-reagin reaction occurs in the nose due to histamine released in response. This causes local vascular dilation with resultant increased capillary pressure, and it also causes increased capillary permeability. Both of these effects cause rapid fluid leakage into the tissues of the nose, and the nasal linings become swollen and secretary. Here again, the conventional treatment is to use anti histamine drugs which can prevent the swelling reaction. However, other products of the allergen- reagin reaction still cause irritation of the nose, still eliciting the typical sneezing syndrome despite drug therapy. Commonly the eyes are also affected in a similar manner.