I found this "What are allergies to insect stings?" at Yahoo news. I think it is very useful of us because sometimes we do not know about it. It said that :
When you are stung by an insect, poisons and other toxins in the insect's venom enter your skin. It is normal to have some swelling, redness, pain, and itching at the site of a sting. An allergic reaction to the sting occurs when your body's immune system overreacts to substances called allergens that are in the venom of stinging insects.
You may not always develop an allergic reaction the first time you are stung. Even if your first reaction to a sting is mild, allergic reactions can get worse with each sting. Your next reactions may become more severe or even life-threatening.
What causes an allergic reaction to insect stings?
An allergic reaction to an insect sting is caused by sensitivity to allergens in the venom of the insect. Your immune system overreacts to these allergens as though they are harmful, foreign substances in your body.
A few types of stinging insects—such as bees, wasps, hornets, yellow jackets, and fire ants—cause most allergic reactions to insect stings.
What are the symptoms?
Symptoms of an allergic reaction can range from mild to severe. Reddening or swelling around the site of a bite is a normal reaction to the insect venom. Minor, localized allergic reactions cause redness, swelling, fatigue, mild tenderness, nausea, itching, and a low fever, but they do not usually require treatment with epinephrine. Mild reactions are not usually an indication that you need allergy shots (immune therapy) to prevent a worse reaction should you be stung again.
A more serious allergic reaction can spread throughout your entire body (systemic reaction) and cause symptoms such as itching, hives, or swelling of the tongue, throat, or other body parts. A life-threatening allergic reaction called anaphylaxis can cause severe symptoms such as confusion, difficulty breathing, shock, and sometimes death.
How are allergies to insect stings diagnosed?
An allergic reaction to an insect sting is diagnosed by a physical exam and a medical history. Once you have recovered from the allergic reaction, you may be given allergy tests to find which types of insect stings you are allergic to and how sensitive you are to the allergens.
How are they treated?
Treatment for insect sting allergies depends on the severity of your reaction. Mild local and systemic reactions can often be treated with cold packs and medications for pain, swelling, and itching. A severe reaction (anaphylaxis) is potentially life-threatening and requires emergency care.
Avoiding future insect stings can prevent allergic reactions. If you have severe allergic reactions, you should carry an allergy kit, which includes antihistamine tablets and an epinephrine injection. You may also want to seek treatment with a series of allergy shots (immunotherapy) to reduce or eliminate your sensitivity to the insect venom.
