It is true that there is no real evidence that Candida causes
infection in the ducts.  I am not convinced though by the reasoning of
Robyn Dunning, however.  The fact is that over many years we noted
that nipple pain due to yeast is associated with deep pain within the
breast, often shooting in nature, and radiating into the shoulder or
back.  This pain often comes on *after* the baby comes off the breast.
And the pain responds to antifungal agents such as ketoconazole or
fluconazole, taken orally.  The baby himself often, maybe even in the
majority of cases does not have thrush, and thrush is often not
irritating for the baby, so the explanation of the positioning does
not do it for me.  Furthermore, the pain often comes on after weeks or
even months of pain free nursing.

Probably we are overdiagnosing yeast in the breast.  But I think there
is a lot of yeast deep in the breast causing a lot of pain.  It gets
there with our overuse of antibiotics.  Here is a good study.  Just
document how many mothers and/or babies get antibiotics in the
perinatal period.  I would bet that 50% barely manage to get out of
hospital without them.  Beta strep, caesarean sections,
etc--antibiotics everywhere.

Jack Newman, MD, FRCPC