This Is What Actually Causes Mastitis

Ever wonder what causes mastitis? As you probably know, this condition is common among breastfeeding women. Up to 33% of new mothers develop mastitis during lactation, according to a 2003 review featured in the journal Disease in Childhood. Its causes range from skin or nipple damage to genetic factors. Poor nutrition may play a role, too.

Most women have sore, painful breasts before or during their period. Stress, weight gain, heavy lifting, and ill-fitting bras may cause these symptoms, too (via the Royal Women's Hospital). Another potential cause is mastitis, an infection that can affect one or both breasts. About a quarter of women stop breastfeeding because of it, as reported by Disease in Childhood.

If you have mastitis, your breasts may swell and feel tender to the touch. You may also experience a burning sensation, flu-like symptoms, and skin redness, as noted by the Mayo Clinic. These symptoms may occur even if you're not breastfeeding, as mastitis can affect anyone, including men. Most times, it's due to a blocked milk duct or bacterial infections. 

What causes mastitis in breastfeeding moms?

Mastitis in breastfeeding moms usually occurs during the first three months after childbirth, according to an article published in the Disease in Childhood (ADC) journal. A common cause is milk stasis, a condition that can lead to blockages in the milk ducts (via the Queensland Children's Hospital). Researchers have several theories about the association between mastitis and milk stasis, as explained in the ADC journal:

  • Milk contains pro-inflammatory substances that may cause swelling
  • Milk proteins may trigger an adverse immune response, leading to inflammation
  • The bacteria in breast milk may trigger infections

The American Cancer Society noted that mastitis may also occur when the mother doesn't fully drain the milk from each breast. This can result in a clogged milk duct, which is a risk factor for mastitis. Cracked nipples may increase your risk of mastitis, too. Women who smoke, have poor eating habits, or wear tight bras are more likely to develop this condition, as reported by the Mayo Clinic. The same goes for those who are overstressed or very tired.

You can get mastitis even if you're not breastfeeding

Breast infections can occur in men and women of all ages. Non-lactational mastitis is often due to smoking, nipple piercing, breast implants, or certain diseases, as explained by the National Health Service (NHS). Eczema and diabetes, for instance, may increase the risk of mastitis in women, regardless of their breastfeeding status. Certain habits, such as tweezing nipple hair, may cause infection, too.

Women with a weak immune system are more likely to develop mastitis, as reported by Johns Hopkins Medicine. You may also be at risk if you've had a lumpectomy followed by radiation therapy. In addition to breast pain and soreness, you may experience fever and headaches.

Now that you know what causes mastitis, take the steps needed to prevent it. The Cleveland Clinic noted that nursing mothers should avoid wearing tight bras and nursing pads. These accessories cause the nipples to stay moist after breastfeeding and may increase the risk of bacterial infection. Air out your nipples after feeding your baby and let them dry before putting on your bra. Since regular smokers are more likely to get mastitis, you may be able to lower your risk by quitting this habit.