Treatment for a nasal septal abscess is similar to that of other bacterial infections. Aggressive broad spectrum antibiotics may be used after the infected area has been drained of fluids.

Potential complications of a nasal septal abscess include cavernous sinus thrombophlebitis, septal perforation, or saddle deformity due to cartilage necrosis.

Both sex are equally affected

Any age group can develop a parapheryngeal abscess but it is most commonly seen in children and adolescents. Adults who are immunocompromised are also at high risk.

Skin abscesses are common and have become more common in recent years. Risk factors include intravenous drug use with rates reported as high as 65% in this population. In 2005 in the United States 3.2 million people went to the emergency department for an abscess. In Australia around 13,000 people were hospitalized in 2008 for the disease.

RPA is usually caused by a bacterial infection originating from the nasopharynx, tonsils, sinuses, adenoids or middle ear. Any upper respiratory infection (URI) can be a cause. RPA can also result from a direct infection due to penetrating injury or a foreign body. RPA can also be linked to young children who do not have adequate dental care or brush their teeth properly.

Closing an abscess immediately after draining it appears to speed healing without increasing the risk of recurrence. This may not apply to anorectal abscesses. While they heal faster, there may be a higher rate of recurrence than those left open.

Infection can occur from:

- Pharynx: acute and chronic infection of tonsil and adenoids

- Teeth: dental infection occurs from lower last molar tooth

- Ear: bezold abscess and petrositis

- Other space: infection of parotid retropharyngeal space

- External trauma: penetrating injuries of neck, injection of local anaesthetic

Nasal septal hematoma is a condition affecting the nasal septum. It can be associated with trauma.

Because the septal cartilage has no blood supply of its own and receives all of its nutrients and oxygen from the perichondrium, an untreated septal hematoma may lead to destruction of the septum. Immediate drainage is necessary. Failure to recognise septal hematomas, or treat in a timely fashion, can cause a saddle nose deformity.

To treat a septal haematoma it is incised & drained to prevent avascular necrosis of the septal hyaline cartilage which depends on diffusion of nutrients from its attached nasal mucosa. Small hematomas can be aspirated with a wide-bore needle. Large hematomas are drained by an incision parallel to nasal floor. Systemic antibiotics are given after the incision and drainage to prevent local infection.

Abscesses are caused by a high-density infection of (usually) common bacteria which collect in one place or another for any variety of reasons. Anal abscesses, without treatment, are likely to spread and affect other parts of the body, particularly the groin and rectal lumen. All abscesses can progress to serious generalized infections requiring lengthy hospitalizations if not treated.

Historically, many rectal abscesses are caused by bacteria common in the digestive system, such as E. coli. While this still continues often to be the case, there has recently been an uptick in the causative organism being staphylococcus, as well as the difficult to treat community-acquired methicillin-resistant S. aureus. Because of the increasing appearance of more exotic bacteria in anal abscesses, microbiological examination will always be performed on the surgical exudate to determine the proper course of any antibiotic treatment.

Retropharyngeal abscess (RPA) is an abscess located in the tissues in the back of the throat behind the posterior pharyngeal wall (the retropharyngeal space). Because RPAs typically occur in deep tissue, they are difficult to diagnose by physical examination alone. RPA is a relatively uncommon illness, and therefore may not receive early diagnosis in children presenting with stiff neck, malaise, difficulty swallowing, or other symptoms listed below. Early diagnosis is key, while a delay in diagnosis and treatment may lead to death. Parapharyngeal space communicates with retropharyngeal space and an infection of retropharyngeal space can pass down behind the esophagus into the mediastinum. RPAs can also occur in adults of any age.

RPA can lead to airway obstruction or sepsis – both life-threatening emergencies. Fatalities normally occur from patients not receiving treatment immediately and suffocating prior to knowing that anything serious was wrong.

If left untreated, an anal fistula will almost certainly form, connecting the rectum to the skin. This requires more intensive surgery. Furthermore, any untreated abscess may (and most likely will) continue to expand, eventually becoming a serious systemic infection.

PTA usually arises as a complication of an untreated or partially treated episode of acute tonsillitis. The infection, in these cases, spreads to the peritonsillar area (peritonsillitis). This region comprises loose connective tissue and is hence susceptible to formation of an abscess. PTA can also occur "". Both aerobic and anaerobic bacteria can be causative. Commonly involved aerobic pathogens include "Streptococcus, Staphylococcus" and "Haemophilus". The most common anaerobic species include "Fusobacterium necrophorum", " Peptostreptococcus", "Prevotella species", and "Bacteroides".

Peritonsillar abscess (PTA), also known as a quinsy, is pus due to an infection behind the tonsil. Symptoms include fever, throat pain, trouble opening the mouth, and a change to the voice. Pain is usually worse on one side. Complications may include blockage of the airway or aspiration pneumonitis.

They are typically due to infection by a number of types of bacteria. Often it follows streptococcal pharyngitis. They do not typically occur in those who have had a tonsillectomy. Diagnosis is usually based on the symptoms. Medical imaging may be done to rule out complications.

Treatment is by removing the pus, antibiotics, sufficient fluids, and pain medication. Steroids may also be useful. Admission to hospital is generally not needed. In the United States about 3 per 10,000 people per year are affected. Young adults are most commonly affected.

Fungi and parasites may also cause the disease. Fungi and parasites are especially associated with immunocompromised patients. Other causes include: "Nocardia asteroides", "Mycobacterium", Fungi (e.g. "Aspergillus", "Candida", "Cryptococcus", "Mucorales", "Coccidioides", "Histoplasma capsulatum", "Blastomyces dermatitidis", "Bipolaris", "Exophiala dermatitidis", "Curvularia pallescens", "Ochroconis gallopava", "Ramichloridium mackenziei", "Pseudallescheria boydii"), Protozoa (e.g. "Toxoplasma gondii", "Entamoeba histolytica", "Trypanosoma cruzi", "Schistosoma", "Paragonimus"), and Helminths (e.g. "Taenia solium"). Organisms that are most frequently associated with brain abscess in patients with AIDS are poliovirus, "Toxoplasma gondii", and "Cryptococcus neoformans", though in infection with the latter organism, symptoms of meningitis generally predominate.

These organisms are associated with certain predisposing conditions:

- Sinus and dental infections—Aerobic and anaerobic streptococci, anaerobic gram-negative bacilli (e.g. "Prevotella", "Porphyromonas", "Bacteroides"), "Fusobacterium", "S. aureus", and Enterobacteriaceae

- Penetrating trauma—"S. aureus", aerobic streptococci, Enterobacteriaceae, and "Clostridium" spp.

- Pulmonary infections—Aerobic and anaerobic streptococci, anaerobic gram-negative bacilli (e.g. "Prevotella", "Porphyromonas", "Bacteroides"), "Fusobacterium", "Actinomyces", and "Nocardia"

- Congenital heart disease—Aerobic and microaerophilic streptococci, and "S. aureus"

- HIV infection—"T. gondii", "Mycobacterium", "Nocardia", "Cryptococcus", and "Listeria monocytogenes"

- Transplantation—"Aspergillus", "Candida", "Cryptococcus", "Mucorales", "Nocardia", and "T. gondii"

- Neutropenia—Aerobic gram-negative bacilli, "Aspergillus", "Candida", and "Mucorales"

In some cases, abscesses may be prevented by draining an existing pseudocyst which is likely to become inflamed. However, in most cases the developing of abscesses cannot be prevented.

Pancreatic abscesses usually develop in patients with pancreatic pseudocysts that become infected. They may also form as a result of fibrous wall formation around fluid collections or penetrating peptic ulcers. Other causes include gall stones or alcohol consumption and, in rare cases, drugs, blunt trauma and following extension abscess from nearby structures.

Anaerobic and microaerophilic cocci and gram-negative and gram-positive anaerobic bacilli are the predominate bacterial isolates. Many brain abscesses are polymicrobical. The predominant organisms include: "Staphylococcus aureus", aerobic and anaerobic streptococci (especially "Streptococcus intermedius"), "Bacteroides", "Prevotella", and "Fusobacterium" species, Enterobacteriaceae, "Pseudomonas" species, and other anaerobes. Less common organisms include: "Haemophillus influenzae", "Streptococcus pneumoniae" and "Neisseria meningitides".

Bacterial abscesses rarely (if ever) arise "de novo" within the brain, although establishing a cause can be difficult in many cases. There is almost always a primary lesion elsewhere in the body that must be sought assiduously, because failure to treat the primary lesion will result in relapse. In cases of trauma, for example in compound skull fractures where fragments of bone are pushed into the substance of the brain, the cause of the abscess is obvious. Similarly, bullets and other foreign bodies may become sources of infection if left in place. The location of the primary lesion may be suggested by the location of the abscess: infections of the middle ear result in lesions in the middle and posterior cranial fossae; congenital heart disease with right-to-left shunts often result in abscesses in the distribution of the middle cerebral artery; and infection of the frontal and ethmoid sinuses usually results in collection in the subdural sinuses.

A nasal septum perforation is a medical condition in which the nasal septum, the cartilaginous membrane dividing the nostrils, develops a hole or fissure.

This may be brought on directly, as in the case of nasal piercings, or indirectly, as by long-term topical drug application, including intranasal ethylphenidate, methamphetamine, cocaine, crushed prescription pills, or decongestant nasal sprays, chronic epistaxis, excessive nose picking and as a complication of nasal surgery like septoplasty or rhinoplasty. Much less common causes for perforated nasal septums include rare granulomatous inflammatory conditions like granulomatosis with polyangiitis. It has been reported as a side effect of anti-angiogenesis drugs like bevacizumab.

Septal perforations are managed with a multitude of options. The treatment often depends on the severity of symptoms and the size of the perforations. Generally speaking anterior septal perforations are more bothersome and symptomatic. Posterior septal perforations, which mainly occur iatrogenically, are often managed with simple observation and are at times intended portions of skull base surgery. Septal perforations that are not bothersome can be managed with simple observation. While no septal perforation will spontaneously close, for the majority of septal perforations that are unlikely to get larger observation is an appropriate form of management. For perforations that bleed or are painful, initial management should include humidification and application of salves to the perforation edges to promote healing. Mucosalization of the perforation edges will help prevent pain and recurrent epistaxis and majority of septal perforations can be managed without surgery.

For perforations in which anosmia, or the loss of smell, and a persistent whistling are a concern the use of a sillicone septal button is a treatment option. These can be placed while the patient is awake and usually in the clinic setting. While complications of button insertion are minimal, the presence of the button can be bothersome to most patients.

For patients who desire definitive close, surgery is the only option. Prior to determining candidacy for surgical closure, the etiology of the perforation must be determined. Often this requires a biopsy of the perforation to rule out autoimmune causes. If a known cause such as cocaine is the offending agent, it must be ensured that the patient is not still using the irritant.

For those that are determined to be medically cleared for surgery, the anatomical location and size of the perforation must be determined. This is often done with a combination of a CT scan of the sinuses without contrast and an endoscopic evaluation by an Ear Nose and Throat doctor. Once dimensions are obtained the surgeon will decide if it is possible to close the perforation. Multiple approaches to access the septum have been described in the literature. While sublabial and midfacial degloving approaches have been described, the most popular today is the rhinoplasty approach. This can include both open and closed methods. The open method results in a scar on the columella, however, it allows for more visibility to the surgeon. The closed method utilizes an incision all on the inside of the nose. The concept behind closure includes bringing together the edges of mucosa on each side of the perforation with minimal tension. An interposition graft is also often used. The interposition graft provides extended stability and also structure to the area of the perforation. Classically, a graft from the scalp utilizing temporalis fascia was used. Kridel, et al., first described the usage of acellular dermis so that no further incisions are required; they reported an excellent closure rate of over 90%. Overall perforation closure rates are variable and often determined by the skill of the surgeon and technique used. Often surgeons who claim a high rate of closure choose perforations that are easier to close. An open rhinoplasty approach also allows for better access to the nose to repair any concurrent nasal deformities, such as saddle nose deformity, that occur with a septal perforation.

Treatment generally consists of surgical drainage, and long-term (6 to 8 weeks) use of antibiotics.

90% of cases are smokers, however only a very small fraction of smokers appear to develop this lesion. It has been speculated that either the direct toxic effect or hormonal changes related to smoking could cause squamous metaplasia of lactiferous ducts. It is not well established whether the lesion regresses after smoking cessation.

Extrapuerperal cases are often associated with hyperprolactinemia or with thyroid problems. Also diabetes mellitus may be a contributing factor in nonpuerperal breast abscess.

Risk factors for infective endocarditis are based on the premise that in a healthy individual, bacteremia (bacteria entering the blood stream) is cleared quickly with no adverse consequences. However, if a heart valve is damaged, the bacteria can attach themselves to the valve, resulting in infective endocarditis. Additionally, in individuals with weakened immune systems, the concentration of bacteria in the blood can reach levels high enough to increase the probability that some will attach to the valve. Some significant risk factors are listed here:

1. Artificial heart valves

2. Intracardiac devices, such as Implantable cardioverter-defibrillators

3. Unrepaired cyanotic congenital heart defects

4. History of infective endocarditis

5. Chronic rheumatic heart disease, which is an autoimmune response to repeated "Streptococcus pyogenes" infection

6. Age-related degenerative valvular lesions

7. Hemodialysis, a medical procedure that filters the blood of individuals with kidney failure

8. Coexisting conditions, especially ones that suppress immunity. Diabetes mellitus, alcohol abuse, HIV/AIDS, and intravenous drug use all fall in this category

More detailed descriptions of these and other risk factors are provided below.

Other conditions that result in high number of bacteria entering into the bloodstream include colorectal cancer (mostly "Streptococcus bovis"), serious urinary tract infections (mostly enterococci), and drug injection ("Staphylococcus aureus"). With a large number of bacteria, even a normal heart valve may become infected.

A more virulent organism (such as "Staphylococcus aureus") can cause infective endocarditis by infecting even a normal heart valve.

Intravenous drug users tend to get their right-sided heart valves infected because the veins that are injected drain into the right side of the heart. In rheumatic heart disease, infection occurs on the aortic and the mitral valves on the left side of the heart.

Other factors that increase the risk of developing infective endocarditis are low levels of white blood cells, immunodeficiency or immunosuppression, malignancy, diabetes mellitus, and alcohol abuse.

Another form of endocarditis is healthcare-associated endocarditis when the infecting organism is believed to be transmitted in a health care setting like hospital, dialysis unit or a residential nursing home. Nosocomial endocarditis is a form of healthcare associated endocarditis in which the infective organism is acquired during stay in a hospital and it is usually secondary to presence of intravenous catheters, total parenteral nutrition lines, pacemakers, etc.

In the post-antibiotic era pattern of frequency is changing. In older studies anaerobes were found in up to 90% cases but they are much less frequent now.