[header] How to reduce allergic swelling [title] Take an antihistamine. [step] This will lower your body's response to the allergen, which can reduce your swelling. You can find an antihistamine over-the-counter, but your doctor could also prescribe one that best fits your needs. 
[substeps] Some antihistamines cause drowsiness. For daytime use, choose one that is labeled as non-drowsy.