mastitis

Mastitis is inflammation of breast tissue that can be infectious or noninfectious. It most commonly occurs in women who are breastfeeding (lactational mastitis) but can also affect nonlactating individuals. The condition typically involves one breast and may present with warmth, tenderness, swelling, redness, and fever or malaise.

Causes of mastitis include milk stasis from incomplete drainage and bacteria entering through cracked or irritated nipples. Staphylococcus aureus is the most common pathogen in lactational cases, with streptococci also implicated. Nonlactational mastitis can have infectious and noninfectious contributors, including inflammatory or autoimmune processes. Risk factors include poor latch or ineffective milk removal, nipple trauma, fatigue, stress, prior mastitis, smoking, and certain breast conditions.

Mastitis is classified as lactational or nonlactational and as acute or chronic. Diagnosis is usually clinical, based on signs and symptoms. Imaging such as ultrasound may be used to exclude an abscess, and culture of milk or tissue can be helpful in recurrent or unusual cases.

Treatment typically includes continuing breastfeeding or milk expression from the affected breast to promote drainage, along with antibiotic therapy targeting common Staphylococcus species (examples include agents such as dicloxacillin or cephalexin, with alternatives for penicillin allergy). Analgesics and warm compresses may relieve symptoms. If an abscess develops or symptoms fail to improve, drainage or further evaluation is required. Nonlactational mastitis is treated with antibiotics directed at likely pathogens, and persistent masses should be evaluated to exclude other conditions, including inflammatory breast cancer.

Prevention focuses on proper latch technique, complete milk drainage, nipple care, and prompt treatment of nipple trauma or blocked ducts. Prognosis is generally good with timely treatment.