mastitis, bovine, bacterial inflammation of the udder in dairy cattle. It is spread during the process of milking, either by machine or by hand, and by flies. The symptoms include inflammation of the udder and clotted, bloody milk. If gangrene develops, death can result. Control of the disease requires sanitary facilities, proper milking procedures, and the segregation of affected animals. The disease is now treated by penicillin in combination with a sulfa drug and other antibiotics.

mastitis, inflammation of the breast. Mastitis most commonly occurs in nursing mothers between the first and third weeks after childbirth, usually of the first child. It is an infection that results when bacteria enter through cracked nipples; the organisms may already be in the body and attack breast tissue weakened by injury. The breast becomes swollen and painful and a high fever may be present. Mastitis is usually easily treated with antibiotics. In severe cases, when an abscess forms within the breast, the suckling baby must be weaned completely. Chronic cystic mastitis is a common, noninfectious but often painful condition in women between 30 and 50 years old, in which cystic nodules develop in the breasts, giving them a lumpy appearance. It sometimes results from a hormonal imbalance. Biopsy may be necessary to distinguish the condition from breast cancer. Another type of mastitis may occur during puberty, and another is associated with other infectious diseases, e.g., mumps and tuberculosis.

Inflammation of the breast. Acute mastitis, usually caused by bacteria, begins almost exclusively in the first three weeks of nursing and can be cured with antibiotics without stopping nursing. The breasts may become swollen, red, hard, and tender; without treatment abscesses may occur. Mastitis can be localized or widespread, and the breast's lymphatic system may be involved. Girls may have brief hormone-induced breast inflammation soon after birth and during puberty. Chronic mastitis usually occurs in systemic diseases (e.g., tuberculosis, syphilis). One rare type is seen mostly in older women with a history of difficult nursing. Some mastitis cases resemble certain cancers.

Learn more about mastitis with a free trial on Britannica.com.