Suggest Treatment For Swelling And Itching Due To Skin Allergy

Sir, My father is suffering from severe skin allergy due to which whole face is swelled and itching is irritating very much eyes cannot be open because of swelling, last few years this happened in the month of summer but swelling never happened. His age is 62 yrs, height is 5'11", weight is 80kg. No other disease. Please help my father he is in real discomfort.