The presence of pus in a lesion is generally a sign of:

The presence of pus — a fluid containing white blood cells, bacteria, and tissue debris — is generally a sign of a bacterial infection. A cosmetologist who sees pus in a lesion on the skin, scalp, or around a nail should not perform the service over the area and should refer the client to a physician, since the area is infected and working on it could spread the infection. Recognizing pus as a sign of infection ties together infection control and scope-of-practice judgment on the exam.