A sore with pus is caused by an infection. Bacterial skin infections can cause pain, inflammation, redness, and pus formation. In addition to local symptoms of infection, systemic signs of infection can occur including fever, body aches, chills, and nausea. Such a sore is generally treated with oral antibiotics, topical antibiotics, or the combination of both types. Treating a sore with pus must be done only by a qualified health care provider to avoid complications.
The color of pus can vary, but is typically white or yellow, though it may also be green, bloody, or very dark. Pus also has a foul odor and is thick in texture. Someone who has a sore with pus should not disturb it by trying to lance the sore with a pin or other sharp object. Even if the object has been sterilized, this is still a dangerous practice because not only can lancing worsen the infection, it can also cause tissue damage. Other methods of treating a sore containing pus include soaking it in warm water every few hours, keeping it covered to avoid bacterial contamination, and taking pain relievers for pain and inflammation.
Boils and carbuncles can also cause a sore with pus. These skin conditions are often located on the back, but can appear on the face, armpits, and genital region. In addition, boils and carbuncles and are sometimes the result of an infected hair follicle. Conditions such as impetigo and staph infections can also cause sores that contain pus. Viral and fungal infections can also skin sores, but they do not produce pus and therefore are not treated with antibiotics.
If a sore with pus appears in the mouth as the result of an infected tooth, a dentist needs to be consulted. An abscessed tooth requires oral antibiotics and possibly oral surgery to drain the abscess. In some cases, the tooth will need to be extracted to prevent complications. Tooth abscesses can be very painful, and if over-the-counter pain relievers fail to reduce pain, the dentist may prescribe narcotic pain relievers.
The health care provider may elect to drain or lance the sore so that the pus can be safely drained. Expressing pus from a wound can alleviate pressure and relieve pain. The procedure is usually minor and only requires a small amount of local anesthetic or numbing gel to numb the area. Following the procedure, the wound is then typically dressed with a sterile bandage to which an antibiotic ointment has been applied.