Place ice wrapped in a washcloth on a wasp sting for approximately 20 minutes each hour, according to WebMD. Wash the site with soap and water, and then apply antibiotic ointment. Use ibuprofen for pain and an antihistamine for itching.
Wasps do not leave their stingers behind, according to KidsHealth. While this means there is no stinger to remove, the wasp is able to sting the individual several times. Stings near the mouth and those that cause a large skin rash or excessive swelling require medical attention. If the individual has had an allergic reaction to a sting in the past or shows signs of a serious reaction, use an epinephrine injector after the sting, and call for emergency assistance or transport the victim to the nearest emergency room. The doctor is likely to prescribe a sting kit, including an epinephrine injector, that the victim keeps with him at all times.
Individuals who suffer 10 or more stings in a single incident should also receive medical care and observation even if they do not experience a severe reaction, according to WebMD. This observation sometimes requires admission to the hospital. The patient's doctor usually orders blood tests for the patient while he is at the hospital.