Milk that is trap in the breast cause breast swelling, or a blocked milk duct could eventually lead to mastitis. Mastitis is usually an infection of the breast tissue. It is common in breastfeeding women.

• Position the baby with the chin or nose pointing to the hard lumpy area while breastfeeding. This will help to drain the plugged duct.
  
  
• Massage the breast before and during a feed to stimulate the flow of milk. The massage can be directed from the blocked area towards the nipple.
  
  
• After a feed, express any remaining milk by hand or pump to drain the breast fully if the baby is unable to do so. Regular expressing may also be needed if the affected area is near the areola. An engorged areola makes it difficult to latch the baby.
  
  
• Pain or anti-inflammatory medication such as ibuprofen can be taken to relieve any pain. This may also facilitate the milk ‘let down’ reflex, which will help clear the blockage.
  
  
• Increase your fluid intake and take fever medication (antipyretics) if you have a fever.

It can occur anytime during lactation but is more common in the first 3 months of lactation. About up to 10 percent of women who breastfeed may be affected.

Idiopathic Granulomatous Mastitis (IGM)

Women not lactating or breastfeeding can also get mastitis. In some of these women, the cause is unknown. This may be resolved with a course of antibiotics, but if IGM persists, it may become complicated and abscesses may result. Surgery to drain the infection and to obtain tissue for biopsy may be needed.

In some severe cases, steroid therapy may be considered if an infective cause is excluded.

Reference: SingHealth