Milk ducts, through which breast milk flows, can sometimes become blocked and hinder milk flow. Milk is then retained in the breast, causing some parts of the breasts to become hard and thick or lumps can be felt in the breasts. This only occurs in parts of the breast and not the entire breast. The area above the lump may be painful or red, but there is usually no fever. The nipple and areola may become misshapen, and sometimes the blood vessels on the surface of the skin of the breast may become raised. White dots may also appear on the nipples.

Causes of Plugged Milk Ducts

Your baby is not completely draining your breast milk, whether from infrequent feeding or limiting their time on the breast.
You have allowed milk to be retained in your breasts for too long.
You have an oversupply and the milk is not removed, or the supply exceeds the demand of your baby.
You are wearing a bra that is too tight, restricting the circulation of breast milk.
You are wearing a bra that is too loose, causing your breasts to sag and press on milk ducts.
You are consuming excessive foods high in fat or oily foods, such as butter and cheese.
You are stressed, causing hormones of lactation to decrease.

Treatment

Use warm compresses on your breast for approximately 5 to 10 minutes before breastfeeding.
Breastfeed on the side with the plugged duct first as your baby’s hunger which cause the baby to suck harder and remove more milk. After nursing, express the remaining milk manually or with a pump to speed up recovery.
Breastfeed at least 8 to 12 times in a 24-hour-period and for at least 15 to 20 minutes on each side.
Ensure that your baby is latched on correctly and position your baby’s chin towards the lump(s) in your breast so the baby can use their tongue more efficiently to drain that area.
Change your baby’s position with each feed so milk is removed from all parts of the breast.
Gently massage your breast while your baby is nursing by massaging the area above the plugged duct and down towards the nipple, to release the plug.
After breastfeeding use cold compresses to reduce pain and swelling. If needed, take painkiller, such as paracetamol.
Wear a supportive bra that is not too loose or too tight.
If your condition doesn’t improve within 24 hours, see your doctor or visit the Breastfeeding Clinic.

References

http://www.memoitchi.com/2011/10/blocked-milk-duct.html

http://www.babymamyshop.com/article?id=59162&lang=th

http://www.babycenter.com/0_plugged-milk-ducts_8494.bc

http://www.drugs.com/cg/breastfeeding-and-plugged-ducts.html