Most mothers who develop mastitis  usually do so within the first few weeks after delivery. Most breast infections occur within the first or second month after delivery or at the time of weaning. However, in rare cases it affects women who are not breastfeeding. Terminology
Popular usage of the term mastitis varies by geographic region. Outside the US it is commonly used for puerperal and nonpuerperal cases, in the US the term nonpuerperal mastitis is rarely used and alternative names such as duct ectasia, subareolar abscess and plasma cell mastitis are more frequently used. Chronic cystic mastitis is an older name for fibrocystic disease. American usage: mastitis usually refers to puerperal (occurring to breastfeeding mothers) mastitis with symptoms of systemic infection. Lighter cases of puerperal mastitis are often called breast engorgement. In this article, "mastitis" is used in the original sense of the definition as inflammation of the breast with additional qualifiers where appropriate. Etymology and pronunciation
The word mastitis () uses combining forms of mast- + -itis. The word mammitis () uses combining forms of mamm- + -itis. They are synonymous in modern usage, and mastitis is the more commonly used synonym. Other animals
Mastitis occurs in other animals as in humans, and is especially a concern in livestock, since milk from the affected udders of livestock may enter the food supply and pose a health risk. It is a major condition in some species, like dairy cows. It is the cause of much unwanted suffering for the dairy cows.
Nonpuerperal mastitis is treated by medication and possibly aspiration or drainage (see in particular treatment of subareolar abscess and treatment of granulomatous mastitis). According to a BMJ best practice report, antibiotics are generally to be used in all nonpuerperal mastitis cases, with replacement of the antibiotics by an antifungal agent such as fluconazole in cases of deep fungal infections, and corticosteroids are to be used in case of granulomatous mastitis (with differential diagnosis to tuberculosis infection of the breast).In idiopathic granulomatous mastitis, successful treatment includes invasive surgical procedures or less invasive treatment with steroid medications. Antibiotics
In lactational mastitis, antibiotics are not needed in the overwhelming majority of cases and should be used only for bacterial infections. For people with nonsevere infections, dicloxacillin or cephalexin are recommended. For people with severe infections, vancomycin is recommended. The length of antibiotic treatment ranges anywhere from 5–14 days. The effects of antibiotics has not been well studied as of 2013. Breast abscess
An abscess (or suspected abscess) in the breast may be treated by ultrasound-guided fine-needle aspiration (percutaneous aspiration) or by surgical incision and drainage; each of these approaches is performed under antibiotic coverage. In case of puerperal breast abscess, breastfeeding from the affected breast should be continued where possible.For small breast abscesses, ultrasound-guided fine needle aspiration such as to completely drain the abscess is widely recognized as a preferred initial management.One recommended treatment includes antibiotics, ultrasound evaluation and, if fluid is present, ultrasound-guided fine needle aspiration of the abscess with an 18 gauge needle, under saline lavage until clear.