Nursing care
Mastitis nursing care: what to assess and what to do first
Written and reviewed by Dana Whitfield, RN, MSN · 5 min read · Updated September 2026
Short answer
Mastitis is a breast infection, usually unilateral, presenting with a red, warm, wedge-shaped area of tenderness, fever, and flu-like malaise. The core nursing action is to keep the patient breastfeeding or pumping from the affected breast, because emptying it is the treatment and stopping raises the risk of abscess.
The clinical picture
Mastitis typically develops in the second to sixth week postpartum, though it can occur at any point during lactation. It usually starts as a plugged duct that goes unresolved, allowing milk stasis and, often, bacterial entry through a cracked or fissured nipple. Staphylococcus aureus is the most commonly implicated organism.
The presentation is usually one-sided: a firm, red, wedge-shaped area of the breast that is warm and painful to touch. Systemic symptoms arrive quickly and can feel disproportionate to the local finding, with fever, chills, body aches, and fatigue that mimic influenza. Patients often describe feeling fine one moment and unwell within hours, which catches many off guard in the early postpartum weeks when they already expect to feel tired.
Assessment: what to look for and in what order
Start with vital signs, since fever and tachycardia establish the systemic picture before you examine the breast itself. Ask about onset, whether one or both breasts are affected, and recent changes in feeding pattern, use of a breast pump, or an infant with a poor latch, since all three predispose to duct blockage.
Inspect and palpate the breast for the classic wedge-shaped area of redness and induration, noting whether it is soft and fluctuant, which would raise concern for abscess rather than uncomplicated mastitis. Check the nipple for cracks or fissures, since these are common entry points for infection. Ask about pain during and between feeds, and assess how effectively the breast is being emptied, since incomplete drainage is the mechanism driving the whole process.
Immediate interventions
The priority intervention is continuing to breastfeed or pump from the affected breast, starting the feed on that side while supply is highest and the infant's suck is strongest. Emptying the breast is the treatment itself, not something to pause until the infection clears — stopping traps milk, worsens stasis, and is a direct route to abscess formation.
Apply warm compresses or take a warm shower before feeding to encourage let-down, and offer massage toward the nipple over the affected area during the feed to help clear the blockage. Administer antibiotics as prescribed, typically a penicillinase-resistant agent effective against Staphylococcus aureus, and give antipyretics and analgesics for fever and pain. Encourage rest and increased fluid intake, both of which are easy to deprioritise with a newborn at home but matter for recovery.
Ongoing nursing management
Reassess the breast at each contact for reduction in redness, tenderness, and induration, and confirm the fever is trending down within 24 to 48 hours of starting antibiotics. If it is not, escalate to the provider, since a fluctuant, non-improving mass suggests abscess formation requiring aspiration or incision and drainage.
Support correct positioning and latch at the breast, since a poor latch is a frequent underlying cause and correcting it prevents recurrence as well as treating the current episode. Encourage varying feeding positions across the day so different ducts are emptied most effectively. Check that the patient is completing the full antibiotic course even once symptoms improve, and document response to treatment clearly for the next shift or the outpatient follow-up.
Patient and family education
Explain plainly why she should keep feeding on the affected side: the breast needs to be emptied regularly, and the infection does not pass through the milk in a way that harms the infant. This reassurance matters, because the instinct when something is red, hot, and infected is to protect the baby by stopping, and that instinct works against recovery here.
Teach frequent feeding or pumping, at least every two to three hours, and full emptying of the affected breast at each session. Review warm compresses before feeds and cold compresses afterward for comfort and to reduce swelling. Advise her to watch for a lump that becomes fluctuant or soft, worsening pain, or fever that fails to respond to antibiotics within two days, any of which should prompt a call back to her provider.
How this appears on the NCLEX
Expect a question describing a postpartum patient with a red, tender, wedge-shaped breast area and fever, asking for the priority nursing instruction. The correct answer is almost always to continue or increase breastfeeding on the affected side, not to discontinue it, and distractor options that suggest stopping breastfeeding or switching entirely to formula are designed to catch test-takers who reason from intuition rather than pathophysiology.
You may also see items testing whether you can distinguish mastitis from a simple plugged duct, mainly on the presence of systemic symptoms like fever, or items asking you to recognise progression to abscess when a mass becomes fluctuant despite antibiotic therapy.
The next step on this is the same as on everything else here: answer questions and read the rationales. Our maternity and newborn practice questions are the closest set to what this page covers.
Common questions
Should a mother with mastitis stop breastfeeding?
No. She should continue breastfeeding or pumping from the affected breast, since emptying it is the treatment and the infection does not pose a risk to the infant through the milk. Stopping increases milk stasis and raises the risk of abscess formation.
What organism most commonly causes mastitis?
Staphylococcus aureus is the most commonly implicated organism, usually entering through a cracked or fissured nipple. Treatment is typically a penicillinase-resistant antibiotic effective against this pathogen.
How is mastitis different from a plugged duct?
Both present with a firm, tender area of the breast, but mastitis is distinguished by systemic symptoms, fever, chills, and flu-like malaise. A plugged duct is usually localised discomfort without systemic illness and often resolves with continued feeding and massage alone.
When does mastitis need more than antibiotics?
If the affected area becomes soft and fluctuant, or fever fails to improve within 24 to 48 hours of starting antibiotics, an abscess should be suspected. This typically requires ultrasound evaluation and aspiration or incision and drainage in addition to antibiotic therapy.