Conditions
Mastitis: symptoms, treatment and when to go in person
Mastitis is inflammation or infection of the breast, usually while breastfeeding, that causes pain, warmth, redness and sometimes fever. By video, the doctor evaluates you and, if appropriate, prescribes a treatment that is compatible with breastfeeding. Keep breastfeeding or pumping. If you notice a soft lump with pus, a fever that isn’t improving, or you feel very ill, get in-person care today.
Is it an emergency? Call 911.
Is this an emergency?
This is not an emergency service. Call 911 or go to the nearest emergency room if you have:
- Confusion, unusual sleepiness or trouble staying awake
- A very fast heartbeat or very fast breathing
- High fever with hard chills, or a very low temperature
- Severe dizziness or fainting
- A swollen or pus-filled breast lump: go in person today, it may be an abscess
Help lines
At a glance
Mastitis
Common symptoms
- Pain, warmth and swelling in part of the breast
- Red skin, often in a wedge or triangle shape
- A lump or hard area in the breast
- Fever and flu-like symptoms, such as feeling unwell, nausea or vomiting
- One breast fuller or larger than the other
- Sore or swollen lymph nodes in the armpit on the same side
- Nipple discharge, which may contain pus
- Other names
- Breast infection · Lactational mastitis
- Treatment
- Keep breastfeeding and, only when the medical evaluation calls for it, an antibiotic compatible with breastfeeding
- Possible complication
- Breast abscess, which is drained in person
On this page(9)
What is mastitis?
Mastitis is inflammation of the breast tissue. According to MedlinePlus, when there is an infection it is usually caused by a common skin bacterium (staph) that gets in through a crack or break in the nipple. It happens mostly in women who are breastfeeding.
It often starts as a clogged milk duct: a tender, sore lump in the breast. If milk doesn’t flow well, the area can become more inflamed.
Breast inflammation or infection that is not related to breastfeeding is different: MedlinePlus explains it can be due to a rare form of breast cancer, and it always needs an in-person evaluation with imaging. We refer you.
How we treat mastitis by video
You see Dr. Diana Nieves Castro, MD, a Puerto Rico–licensed general practice physician with several years of emergency-department experience, in English or Spanish. A video visit saves you from going out with a newborn. The doctor asks how long you have had symptoms, whether you have a fever, whether the pain is in one breast or both, whether there is a lump, how breastfeeding is going and which medicines you take.
If appropriate, the doctor prescribes a treatment chosen to be compatible with breastfeeding, and we send your prescription to your pharmacy. We never promise an antibiotic before the evaluation: read can telehealth prescribe antibiotics. If the doctor suspects an abscess or something that needs an exam, she tells you to go in person that same day. Mastitis is part of our urgent care online.
Your privacy matters: join from a private place; visits are not recorded. If the doctor needs to see the area, it happens only inside your secure visit link; don’t send photos by email or text message.
We do not provide pregnancy or prenatal care. If you are under 21, your parent or legal guardian must be on camera for the whole visit and show photo ID.
Your doctor
Dr. Diana Nieves Castro, MD
General practice physician
Several years of emergency-department experience.
Founding Executive Director of The Health Initiative.
Your visit in 3 steps
Request a visit online 24/7 — we confirm your time by email or text.
Request your visit.
Book a visit and choose "Doctor visit". You pay by card when you request it.
See the doctor by video.
We send you a secure video link. It works on your phone, tablet or computer.
Get your plan.
If appropriate, the doctor prescribes and we send your prescription to your pharmacy. If needed, we refer you for an in-person evaluation.
What the visit costs
Mastitis is handled in a US$79 doctor visit, with no membership. You pay by card when you request the visit, and you get a full refund if the visit can’t take place. We do not bill insurance; the pharmacy charges separately. See all prices.
Mastitis symptoms
According to MedlinePlus, symptoms are usually on one side only:
- Pain, warmth and swelling in part of the breast
- Red skin, often in a wedge or triangle shape
- A lump or hard area in the breast
- Fever and flu-like symptoms, such as feeling unwell, nausea or vomiting
- One breast fuller or larger than the other
- Sore or swollen lymph nodes in the armpit on the same side
- Nipple discharge, which may contain pus
Treatment: keep breastfeeding
Don’t stop breastfeeding. MedlinePlus and the Office on Women’s Health (OWH) advise continuing to breastfeed, or to pump, including on the affected side, while you are treated. This keeps the milk flowing.
Rest and look after yourself. Drink fluids, rest as much as you can and wear a supportive bra that isn’t tight. If appropriate, the doctor tells you which pain reliever you can take while breastfeeding.
An antibiotic, if needed. When there is an infection, MedlinePlus explains that antibiotics work very well and mastitis usually clears quickly. The doctor decides whether you need one and chooses one that is compatible with breastfeeding.
If there is an abscess, a pocket of pus, it has to be drained with a needle guided by ultrasound or with a procedure. That is done in person.
When to go in person the same day
Get an in-person evaluation today, with your OB-GYN or at an urgent care center, if:
- You notice a swollen lump that seems to have pus or fluid in it, or a lump that won’t go away: it may be an abscess
- You don’t feel better within 24 hours, or your fever doesn’t improve with treatment
- You have symptoms in both breasts
- You see pus or blood in your milk, or red streaks on the skin of the breast
When to go to the ER
An infection can spread to the blood (sepsis). For your safety, go to the emergency room or call 911 if you have:
- Confusion, unusual sleepiness or trouble staying awake
- A very fast heartbeat or very fast breathing
- High fever with hard chills, or a very low temperature
- Severe dizziness or fainting
- Mottled skin, or you feel very ill
How we care for you
We evaluate, diagnose and treat; if needed, we give you a lab order for a lab near you.
We see adults and children of all ages. Patients under 21: a parent with patria potestad (parental authority) or a legal guardian is on camera for the whole visit and shows photo ID.
Real-time video visit. We send you a secure video link. It works on your phone, tablet or computer.
If appropriate, the doctor prescribes and we send your prescription to your pharmacy. We do not prescribe controlled substances.
You must be physically in Puerto Rico during the visit (visitors, tourists and cruise passengers are welcome).
In an emergency, call 911.
Frequently asked questions
Can I keep breastfeeding with mastitis?
Can I get mastitis treatment by video?
What is the difference between a clogged milk duct and mastitis?
Is a breast lump always mastitis?
About this page
Author: The Health Initiative
Medical care provided by Dr. Diana Nieves Castro, MD (PR license 24027)
Disclosure: Founding Executive Director of The Health Initiative
Published: 2026-10-02 · Updated: 2026-10-02
Sources (3)
- Breast infection (MedlinePlus, NIH) (opens in a new tab) (accessed 2026-10-02)
- Sepsis (MedlinePlus, NIH) (opens in a new tab) (accessed 2026-10-02)
- Common breastfeeding challenges (Office on Women’s Health, HHS) (opens in a new tab) (accessed 2026-10-02)