The most common cause of pus in the nose is an infection located somewhere inside the nasal cavity. Often this is caused by a primary disease that eventually develops into a sinus infection. Other times, a sore or pimple can cause pus in the nose that comes from the sore itself. When it is caused by a sinus infection, other symptoms are often present. Most sinus infections will go away on their own without treatment, but some may need antibiotic treatment.
A common reason for pus in the nose is a sinus infection. These usually occur when one has a cold or other respiratory illness. Bacteria or viruses can build up in the nasal cavities and cause severe headaches, nasal congestion, runny nose, and sometimes pus drainage. Not all sinus infections will cause pus in the nose that can be seen. Some people may also mistake pus for excessive mucus production in the nose.
Sinus infections are often treated with antibiotics, but they are not effective in all cases. Infections caused by viruses, rather than bacteria, will not respond to antibiotics. Patients who have a sinus infection should rest as much as possible and blow their nose frequently to remove some of the bacteria or viruses. In most cases, infections will heal naturally after a few days. Over time, serious infections can spread to the ears and lead to an ear infection.
Another possible cause of pus in the nose is a sore or pimple inside the nasal cavity. This could occur due to an injury, or a blocked pore or duct in the case of a pimple. Folliculitis, or infection of the hair follicles, can also occur. Staph bacteria are commonly found in the nose and can sometimes lead to pore or sweat gland infections. This would lead to a pimple-like rash commonly seen on the face. Blackheads can also occur inside the nose.
If the pus is being caused by a sore inside the nose, it will usually resolve over time. Severe ulcers may need to be treated with an antibiotic ointment or oral antibiotics. Pain and bleeding can also occur. If the sores last more than a week or heal and then return, a doctor should be notified. More sores will not cause pus to come out of the nose unless they have become severely infected. Pimples can "pop" and cause a small amount of pus to come out of the nostril.