by Jack Newman, MD, FRCPC
Mastitis is a bacterial infection of the breast which usually occurs in breastfeeding mothers. However, it can occur even in women who are not breastfeeding or pregnant, and can even occur in small babies. Nobody knows exactly why some women get mastitis and others do not. Bacteria may gain access to the breast through a crack or sore in the nipple, but women without sore nipples also get mastitis.
Mastitis needs to be differentiated from a plugged or blocked duct, because the latter does not need to be treated with antibiotics, whereas mastitis often, but not always, does require treatment with antibiotics. A plugged duct presents as a painful, swollen, firm mass in the breast, often with overlying reddening of the skin, similar to mastitis, though not usually as intense. Mastitis, though, is usually associated with fever and more intense pain and redness of the breast. As you can imagine, it is not always easy to differentiate a mild mastitis from a severe blocked duct. A blocked duct can lead to mastitis.
In order to make a diagnosis of mastitis, there must be an area of hardness, pain, redness and swelling in the breast. The absence of such an area in the breast means that the mother does not have mastitis. Flu-like symptoms or fever alone are not enough to make the diagnosis of mastitis. Shooting pains in the breast without an area of hardness are not mastitis. These are more likely caused by a yeast infection and thus should not be treated with antibiotics.
As with almost all breastfeeding problems, a poor latch, and thus, poor draining of the breast sets up the situation where mastitis can occur.
Blocked ducts will almost always resolve spontaneously within 24 to 48 hours after onset. During the time the block is present, the baby may be fussy when nursing on that side, as milk flow may be slower than usual. Blocked ducts can be made to resolve more quickly by: