What is Mastitis?
Mastitis is the medical term for inflammation of the breast. Most acute cases are associated with infection especially during the first month of breastfeeding. Chronic cases may be related to secondary infections often associated with an underlying disorder or obstruction of the breast ductal system known as periductal mastitis. Since most cases of breast inflammation are due to an infection during breastfeeding, it can be broadly divided into lactational and non-lactational infections.
Mastitis During Breastfeeding
Lactational Breast Infection
Lactational breast infections usually arise in the first 4 to 6 weeks of breastfeeding. It occurs when fissures and cracks develop on the nipple as a result of breastfeeding and this allows bacteria to invade the underlying tissue. Lactational mastitis is usually a superficial infection, like cellulitis, and may lead to single or multiple abscesses more often on the periphery of the breast. Single or multiple breast abscesses may form and with diffuse infections that are left untreated, extensive necrosis may occur.
Infection initially involves only one lactiferous duct, associated ductules and glandular lobules. Milk stasis may be one of the precipitating factors and therefore drainage is advised to minimze the risk and severity of lactational mastitis. With time, however, the infection may spread throughout the entire breast. The most common causative pathogen is Staphylococcus aureus followed by Staphylococcus epidermidis and streptococci. Staphylococci tend to cause a more localized inflammation in comparison to the diffused infection seen with streptococci.
Mastitis Without Breastfeeding
Non-Lactational Breast Infection
Non-lactational breast infections may occur with trauma to the breast, post-operatively, in women with poorly managed diabetes mellitus, HIV infection and even rheumatoid arthritis. The infections are more often seen around and away from the areola (peripheral). However, it is a rare entity compared to acute mastitis associated with breastfeeding (lactational mastitis).
Chronic non-lactactional mastitis may be related to keratizination of epithelium lining the nipple ducts. Keratin plugs block the ducts which leads to inflammation. This is known as periductal mastitis. A secondary bacterial infection and abscess formation may arise. It can also lead to the development of a fistula. This type of mastitis is more often seen in female smokers and associated with conditions like an inverted nipple. Read more on deformed nipples.
Signs and Symptoms of Breast Infections
Pain, tenderness, swelling and redness of the breast are the more common symptoms and may occur with inflammation with/without infection. In the early stages, women many not experience intense symptoms and simply report discomfort when wearing a brassiere or find undergarments too tight/small.
With infections, other signs and symptoms like a fever, headache and fatigue may be present. Pustular discharge, especially yellow to green discharges that have an offensive odor with/without blood may be seen in acute mastitis. Read more on breast secretions. In the event of an abscess, a localized elevated area that is tender which is red and warm to the touch may be seen.