Does antihistamine treatment treat insect bites?

An insect bite can trigger a local immune response with itch, redness, and swelling. An oral antihistamine may dampen the itch and reduce the urge to scratch. The bump can still take time to settle, and the medicine does not kill an insect left in the skin, remove a retained stinger, or clear bacteria introduced through broken skin. Reactions vary with the insect and with your sensitivity.

Gently wash the area, use a cool compress, and avoid scratching. Follow the product directions if you use an antihistamine, and check whether it can cause drowsiness before driving or combining it with alcohol or other sedating medicines. Watch the size, warmth, pain, and drainage of the area. A pharmacist or clinician can help choose treatment when the itch is persistent or the bite is uncertain.

Call emergency services for trouble breathing, swelling of the mouth or throat, faintness, or a rapidly spreading reaction after a bite or sting. Seek medical care if redness and warmth spread, pain increases, pus develops, or fever appears. Assessment is also sensible after a bite near the eye, inside the mouth, or from an unknown animal or insect.

Does this look like a simple bite reaction? Should I use an antihistamine, and could it make me drowsy? What changes would suggest infection or a severe allergy?