Primarily, the most common cause of white pus is an infection, often induced by bacteria or any other foreign substances. In some cases, pus can be caused by a suppurative, or something that forces the pus to come out. White pus in itself is not a bad thing; it is actually a symptom of something foreign that the body is fighting against. It is also an indication that the immune system is functioning properly by defending the body from infections. Usually, pus is of a whitish to yellowish color, but it can appear to be greenish, bluish, or even brownish, depending on the bacteria and the pigment it is generating.
The reason why some pus is white is because it is usually made up of white blood cells. When the body experiences an infection, the bone marrow produces more white blood cells, all of which rush directly to the infection to fight off and “eat” the bacteria coming in. After the process, the white blood cells eventually die off and the waste matter both from the bacteria and the white blood cells on the infection site and becomes the pus. If the pus is located just beneath the skin, it can be called a “pimple,” such as often seen on the face. If the pus is located deeper into the tissues, doctors usually label this as an “abscess.”
An everyday situation in which one can experience the presence of pus is when one gets wounded. The surface, such as hard soil, on which the skin is scraped, usually contains different kinds of bacteria, which can then be transferred to the open wound. It is also not uncommon for debris, such as wood splinters, to get wedged in the skin. As a result, the white blood cells “attack” the foreign substances and the bacteria and create white pus. In some cases where foreign objects such as unsterilized needles or bullets go deeper within, it can form an abscess inside the tissue.
Visible white pus can also be caused by a suppurative agent that forces the infection to come to a “head” or a “point.” Doctors often advise their patients not to “pop” or drain the pus because it will eventually be reabsorbed by the body and flushed out as toxins by the liver or the kidney. If the pus, however, has remained in the area for an extended period, the dormant bacteria left in the pus may become active and cause worse infections, making it necessary for the pus to be drained. One can grind or boil the leaves and roots from different suppurative plants such as the banyan tree, sugar-apple tree, or the common grape vine and apply them externally to the infection site to induce suppuration. If the white pus is significantly visible, doctors can easily drain it out by using a syringe.