Mastitis: Symptoms, Causes and How to Prevent It Effectively

Mastitis is an inflammatory condition that affects the mammary gland and is commonly associated with breastfeeding. It is more common during the first three months of breastfeeding, although it can occur at any point during this process. It can even lead to inflammatory mastitis, bacterial mastitis, phlegmon, breast abscess, galactocele and subacute mastitis.

In this post, our midwives at Happymami have reviewed the latest scientific evidence to give you the best information on lactational mastitis, including the causes, the symptoms, the available treatments and the strategies to prevent it from developing. We will also provide useful information for women who breastfeed their babies, with the aim of minimising the risk of developing this condition and guaranteeing effective, comfortable breastfeeding.

What is mastitis?

Mastitis is an inflammation of the mammary gland that can occur in women who breastfeed, although it can also affect women who are not breastfeeding. In most cases, mastitis occurs during breastfeeding and is caused by a bacterial infection in the breast.

The infection usually occurs when bacteria enter the nipple through a crack or a sore in it. The symptoms of mastitis include breast pain, redness, heat, swelling and fever. Treatment usually includes the use of antibiotics, as well as measures to relieve pain and maintain the flow of milk through the milk ducts. It is important that women who breastfeed continue to breastfeed during treatment for mastitis, as this helps to empty the milk from the breast and reduce inflammation.

How common is mastitis?

Lactational mastitis is a common condition in women who breastfeed their babies, with an incidence that can vary from one study to another, but which has been calculated to occur in a range of 2% to 25% of breastfeeding mothers. It is important to highlight that the incidence of mastitis requiring hospitalisation is low, as seen in a cohort that included 136,459 first-time mothers, where only 127 women were hospitalised for mastitis, an incidence of 9 per 10,000 births.

The risk of recurrence of mastitis in women with a previous history of mastitis during breastfeeding is higher than in women with no previous history.

What is mastitis and why does it happen?

Lactational mastitis is mainly caused by poor milk drainage due to trauma to the nipple, inflammation or compression of one or more milk ducts. If this drainage problem persists, the stagnant milk becomes infected and lactational mastitis develops.

In addition, mastitis can be related to breastfeeding problems, such as sore or cracked nipples, partial or complete blockage of the milk duct, an excess of milk, infrequent feeding, rapid weaning, illness in the mother or the baby, maternal stress or excessive fatigue, and maternal malnutrition.

The pathogenesis of lactational mastitis is complex and may include interactions between the breast-associated microbiota and specific host factors. The infection can progress to the formation of local abscesses if it is not treated promptly. Risk factors include a previous history of mastitis, poor milk drainage, cracked nipples, the use of cream on the nipples and the use of a breast pump.

In lactational mastitis, most cases are caused by a bacterium called Staphylococcus aureus, and in some cases this bacterium can be resistant to antibiotics. One study found that methicillin-resistant Staphylococcus aureus (MRSA) has become an important pathogen in cases of mastitis during breastfeeding, being the most common pathogen in women hospitalised for this condition.

How do I know if I have mastitis?

Lactational mastitis is a common condition that can occur during the first three months of breastfeeding, characterised by a painful, swollen and red breast.

This mastitis is most common during the first three months of breastfeeding. The first symptoms can be breast engorgement due to poor milk drainage, probably related to trauma to the nipple, with the resulting inflammation and compression of one or more milk ducts.

It will be considered infectious mastitis (as breast milk contains bacteria) if the symptoms persist for more than 12 to 24 hours. These cases of infectious mastitis during breastfeeding usually present with a firm, red, painful and inflamed area on one breast associated with a fever >38.3°C in a breastfeeding mum, and milk secretion may be reduced. You may also have muscle aches, chills, general malaise and flu-like symptoms.

Types of mastitis

• Non-infectious mastitis: treatment of non-infectious mastitis during breastfeeding consists of symptomatic treatment to reduce pain and inflammation (e.g. non-steroidal anti-inflammatory drugs, cold compresses) and complete emptying of the breast through continued breastfeeding, pumping and/or hand expression.
• Infectious mastitis: Treatment of infectious mastitis during breastfeeding includes the above measures plus the administration of antibiotic therapy active against S. aureus.

How long does mastitis last?

The duration of mastitis can vary depending on the severity of the infection and the treatment received. In general, with appropriate treatment, most cases of mastitis during breastfeeding start to improve within 1-2 days and resolve completely in around 1-2 weeks. However, in some cases it can take longer to heal completely. If the symptoms get worse or do not improve after a few days of treatment, it is important to seek medical attention again.

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What happens if I have mastitis and breastfeed?

It is safe to carry on breastfeeding if you have mastitis, and in fact it is important to continue breastfeeding or expressing milk from the affected breast to relieve breast engorgement and prevent the milk ducts from becoming blocked.

Breast milk is safe for your baby and contains antibodies that can help prevent infection. However, it is important that the mother washes her hands frequently and uses a good breastfeeding technique to avoid spreading the infection. In addition, if your doctor has prescribed antibiotics, you should take them as directed to eliminate the infection completely.

Mastitis and bottle-feeding

When you have mastitis there is no need to stop breastfeeding; in fact, it is recommended that you continue offering the breast to your baby. But if in your case you need a bottle, we should avoid generic bottles, because as they are different from your breast, they can confuse your baby and make you lose your breastfeeding relationship.

So the best solution is to offer a custom-designed Happymami bottle, with which you will get the bottle that most closely resembles your breast, preventing nipple confusion in your baby and protecting your breastfeeding relationship.

How is mastitis diagnosed?

To diagnose mastitis, we rely on the clinical signs; laboratory tests are usually not necessary. There are cases in which a laboratory test will be necessary to guide the choice of antibiotic, especially if we are dealing with a severe infection, acquired in hospital or one that does not respond to the initial empirical antibiotics.

If, after this first treatment, the mastitis does not respond within 48 to 72 hours, imaging will be useful to distinguish mastitis from a breast abscess.

How do you treat mastitis?

In the case of uncomplicated mastitis during breastfeeding, the first step of treatment involves various measures to reduce pain and ensure the continuous production of milk through the milk ducts:

• To relieve pain, use cold compresses or soak a cloth in warm water and place it on your breast. A warm shower or bath can also help.
• You can also use paracetamol or ibuprofen to relieve pain and fever (aspirin should be avoided).
• Rest and drink plenty of fluids.
• If you are breastfeeding, carry on, starting with the sore breast first.
• Avoid tight clothing or bras

Treatment for infectious mastitis

If in your case we are already talking about infectious mastitis (the symptoms persist for more than 12 to 24 hours and are accompanied by fever or systemic symptoms such as malaise). Treatment includes antibiotic therapy against S. aureus (the most common causative agent) in addition to the above measures.

The optimal duration of therapy is not certain; 10 to 14 days can reduce the risk of relapse, but shorter courses (5 to 7 days) may be used if the response to therapy is rapid and complete. In patients with severe mastitis or an abscess, once there are signs of clinical improvement with no evidence of systemic toxicity, antibiotics can be switched from parenteral to oral therapy.

In a study in which patients were observed, it was found that the use of antibiotics together with emptying of the mammary gland to treat infectious mastitis during breastfeeding increased the rate of symptom improvement within two weeks from 50% to 96%.

If there is no clinical improvement within 48 to 72 hours, an ultrasound assessment should be performed to determine whether there is an underlying abscess.

Preventing mastitis

There is not enough evidence to recommend preventive treatment with probiotics in pregnant women who have no history of lactational mastitis. A randomised study showed that the administration of a Lactobacillus probiotic during the last stage of pregnancy can reduce the likelihood of mastitis during breastfeeding in pregnant women with a history of this condition.

The trial included 108 women with a history of infectious mastitis in previous pregnancies, and those who received Lactobacillus salivarius PS2 orally had a lower incidence of mastitis compared with those who received a placebo (25% versus 57%).

Recurrence of mastitis

Recurrent mastitis is not common, but it can be caused by inadequate or incomplete antibiotic therapy and/or problems with breastfeeding technique that result in incomplete milk drainage. In cases of recurrent mastitis in the same location and/or that does not respond to antibiotic treatment, the possibility of inflammatory breast cancer should be considered.

Conclusion on mastitis

In conclusion, mastitis is an inflammation of the breast tissue that can cause pain, redness, heat and swelling in the affected breast. It affects women who breastfeed more often and can be caused by bacteria entering the breast through cracks in the nipple or blocked ducts.

Treatment consists of antibiotics and frequent emptying of the milk through breastfeeding or hand expression. Measures can also be taken to relieve pain, such as the use of cold or warm compresses and painkillers.

If mastitis is not treated properly, it can become a serious and potentially life-threatening infection, such as a breast abscess. Therefore, it is important to seek medical attention if mastitis is suspected and to follow the doctor's recommendations to avoid complications.

Mastitis references

1. J Michael Dixon, MD Anees B Chagpar, MD, MSc, MA, MPH, MBA, FACS, FRCS(C)Daniel J Sexton. Lactational mastitis . Uptodate.com. 2023 . Available here
2. Spencer J. Patient education: Common breastfeeding problems (Beyond the Basics) . Uptodate.com. 2023 . Available here.