mastite

Mastite, or mastitis, is an inflammatory condition of the mammary gland or breast tissue. It can affect humans and animals with mammary glands, most often occurring in breastfeeding individuals and in dairy cattle. The condition is usually caused by bacterial infection but can follow milk stasis, trauma, or immune suppression.

In humans, mastitis most commonly arises during lactation when milk becomes blocked or bacteria enter the nipple, but nonlactational mastitis can occur. Common pathogens include Staphylococcus aureus, Streptococcus species, and Escherichia coli. In dairy animals, mastitis is a major welfare and economic issue, caused by contagious bacteria such as Staphylococcus aureus and Streptococcus agalactiae, as well as environmental bacteria.

Symptoms vary by context. In people, signs include breast tenderness or pain, redness and warmth of the breast, swelling, fever, malaise, nipple fissures, or flu-like symptoms. In animals, signs include udder swelling and heat, hardness of the udder, reduced milk yield, changes in milk appearance, and sometimes systemic illness.

Diagnosis is based on clinical examination and history. In humans, milk culture can identify the causative organism and guide antibiotic choice. Imaging such as ultrasound may be used in uncertain cases. In animals, diagnosis relies on physical examination, cow-side tests, somatic cell counts, and milk culture.

Treatment aims to relieve symptoms, control infection, and restore milk flow. For humans, continuing breastfeeding or milk expression is often recommended if feasible, along with analgesics and antibiotics chosen for safety during lactation. For animals, veterinary guidance is essential, with appropriate antibiotic therapy and improved milking hygiene. Prevention focuses on proper milking technique, hygiene, and prompt treatment of breast or udder problems.