After being stung by a wasp and experiencing allergic reactions, the first step is to treat the sting site. You can wash the wound with soap and water or an alkaline solution to reduce the absorption of toxins. Additionally, thoroughly disinfect with iodine. Also, inspect the sting site for any remaining stinger; if present, remove it to decrease further toxin absorption and alleviate symptoms. For skin allergies, oral antihistamines such as levocetirizine or loratadine can be taken to ease symptoms. If the allergic skin reaction is severe and covers a large area, and oral medications are ineffective, intravenous administration of antihistamines such as dexamethasone, calcium gluconate, and high doses of vitamin C can be considered for treatment to relieve symptoms. It is also important to watch your diet and avoid spicy, irritating foods and seafood. (Please follow medical advice regarding medication use.)