In cases of recurring or resistant thrush, in addition to  ruling out
secondary eczema or infection, I help the mother hunt for the source
of reinfection.  Some culprits include: bras, nightgowns, bath towels,
 bathing suits, bed sheets, bottle nipples, pacifiers, cloth diapers,
teething toys, wash cloths, another member of the family, ..... I
have had good luck eliminating the thrush when we identify the source.
  Have the mother think of everything she touches, the baby touches,
anythuing that touches her breasts or goes in the baby's mouth. Many
times you will hear ah ha!  Cathy Liles