What should you know about canine mastitis antibiotics?

Mastitis is inflammation of breast tissue. It can occur during breastfeeding when milk is not draining well, and bacteria can enter through a damaged nipple or nearby skin. Antibiotics are considered when a bacterial infection is suspected, or when symptoms do not improve with supportive measures. The medicine, dose and course depend on your history, allergies, breastfeeding status and examination findings.

Warmth, tenderness, swelling, a firm area and fever can occur. These features need assessment because a painful collection of pus, called an abscess, may need drainage as well as medicine. Do not use leftover antibiotics or someone else’s prescription.

Arrange a medical assessment if breast pain, redness or fever is developing. Continue gentle feeding or expressing if you are breastfeeding and it is comfortable; sudden stopping can worsen fullness. Rest, drink fluids and use a cool pack for comfort. Take an antibiotic exactly as prescribed and finish the advised course unless the prescriber changes it. Ask whether the medicine is suitable for your baby and what to do if you miss a dose.

A clinician may check the breast, nipple and nearby lymph nodes, and may arrange imaging if a lump persists or an abscess is suspected. Other antibiotic-treated conditions, such as [Cellulitis](/conditions/cellulitis/), require different assessment and should not be self-diagnosed from a breast symptom.

Seek urgent medical help for rapidly spreading redness, severe or worsening pain, faintness, confusion, breathing difficulty, repeated vomiting or a very high fever. Prompt review is also needed if you feel increasingly unwell, cannot keep fluids down, or a tender lump remains despite treatment. These signs can indicate a deeper infection or a complication that needs hands-on care.

Ask: Is this more consistent with inflammation, infection or an abscess? Which antibiotic is appropriate with my allergies and breastfeeding status? When should pain and fever begin to settle? Do I need imaging or a follow-up examination? What should I do if symptoms worsen or return after the course?