Breast abscess overview

# Overview
Breast abscess is a very rare infectious disease which is defined as a local collection of pus beneath the skin of the breast. It is the common complicated form of the breast inflammation (mastitis).

# Historical perspective
In 1841, Dr. Jonathan Toogood reported a case of breast abscess.

# Classification
Breast abscess is classified according to the anatomical location of the abscess into subcutaneous, subareolar, interlobular, central and retromammary and the lactation state of the patient either lactational or non-lactational.

# Pathophysiology
Following untreated mastitis, breast abscess could occur. 
Breast abscess is usually caused by staphylococcus aureus bacterial infection to an injured breast skin. Staphylococcus aureus could form abscess by secretion of several killing agents like enzymes and toxins which causes breast tissue necrosis. In a reaction to these bacterial substances, assembled white blood cells in this tissue produces anti-bacterial anti-bodies that help in killing the bacteria. However, these cells cause damage to the soft tissue contributing in the abscess formation. 
As the breast abscess is the complicated form of mastitis, the pathophysiology is mostly like the mastitis pathophysiology.

# Causes
Breast abscess is a bacterial infectious disease that is caused by many bacterial pathogens and it may also be caused by fungi mostly common candida through the infant mouth. The most common bacterial pathogen causing breast abscess is the staphylococcus aureus. It is almost caused by the same pathogens causing mastitis. To understand the common species causing breast abscess we can classify them into gram positive and gram negative bacteria. 

# Differentiating breast abscess from other conditions
Breast abscess should be differentiated from other diseases that cause swelling in the breast skin. These diseases are like mastitis, inflammatory breast cancer, galactocele, plugged duct, Mondor's syndrome and fibroadenoma.

# Epidemiology and Demographics
A breast abscess is a rare disease with an incidence of 3,000-11,000 cases only per 100,000 mastitis patients. There is no significant prevalence concerning the abscess.

# Risk Factors
The most important risk factor that can participate in breast infection and abscess formation is the trauma. Other risk factors include duct ectasia, obesity, diabetes mellitus and insect bites.

# Natural History, Complications and Prognosis
The breast abscess will rupture around its location on the skin if kept untreated. Complications of breast abscess include milk fistula and antibioma. Breast abscess prognosis is usually good with appropriate treatment but recurrence may occur.

# Diagnosis

## History and Symptoms
Breast abscess can be noticed first by the patient like a breast mass or lump. The patient usually has current breast infection(mastitis) or history of the infection. The symptoms include fever, fatigue, skin induration and nipple discharge.

## Physical examination
Patients with breast abscess are remarkable for the breast tenderness, swelling, redness and warmth of the skin. 

## Laboratory Findings
Breast abscess diagnosis depends only on the clinical manifestations of the abscess not the laboratory findings. However, a culture could be taken from the milk and the pus just to decide the antibiotics needed for the treatment.

## Electrocardiogram
There is no significant changes in the EKG of breast abscess patients.

## Chest X Ray
There is no x-ray changes in the chest of breast abscess patients.

## CT Scan
CT scan is not used to diagnose the breast abscess. However, it can be performed to exclude other diseases like breast cancer.

## Ultrasound
Ultrasonography is an important imaging approach in diagnosing and surgical treatment of breast abscess.

## Other imaging findings
Mammography can be used in breast abscess diagnosis besides the US as it helps in differentiating between the breast abscess and cancer.

# Treatment

## Medical therapy
Medical treatment is important alongside the surgical treatment.Breast abscess is treated with antibiotics like flucloxacillin, dicloxacillin or erythromycin as a supportive line to the surgical measures and to prevent the abscess recurrance. The choice of the antibiotic medications depends on the pathogen type however, the high possibility of the pathogen to be staphylococcus aureus leads to start the antibiotic medications before the result of the discharge culture..

## Surgery
The first line of breast abscess treatment is US guided needle aspiration and surgical drainage of the abscess.

## Prevention
Primary prevention of breast abscess relies on mitigation of the risk factors and improving patient hygiene particularly in lactating patients. It relies especially on the mother and infant hygiene. Breastfeeding is advised to be continued after the abscess drainage to prevent recurrence.