New swelling after a bite or sting

Symptoms that occur after an insect bite or sting are caused by the injection of venom or other substances into your skin. With minor bites, the reaction covers a small area. A bump rises on your skin at the site of the bite, the area may itch for a few hours, and the skin irritation and discomfort will go away over a few days. It is not uncommon for swelling from a bite or sting around a hand or foot to be worse during the second 24-hour period. Home treatment is often all that is needed.

A more serious reaction will cause redness and swelling beyond the bite site. A major reaction is defined as redness and swelling across two major joints, such as from below the ankle to above the knee or from below the elbow to above the shoulder. Moderate to severe swelling requires a visit to a health professional and often a prescription medication to reduce the swelling.

An allergic reaction can cause swelling elsewhere in the body besides the bite or sting site, especially on the face, tongue, throat, hands, and feet (angioedema). An allergic reaction requires emergency care.

It is often hard to tell the difference between an allergic reaction and signs of early infection. Both may cause redness and swelling. An infection often causes tenderness at the site of the infection. The redness and swelling of an infection often spreads and tends to move toward the body, following the lymph nodes. An allergic reaction often causes more itching than tenderness.