Long term thrush that not been treated effectively or for long enough?
Long term infection of some other kind?
Could mum have skin swab and milk culture; swab taken from baby's nose and
mouth for culture?
Long term poor positioning, baby lying on its back will have to hold on extra
hard to keep breast in mouth, v. difficult to swallow when head is turned
because of body position.
Reason for 'clicking' sound needs to be explored
Can you see where she normally sits to feed baby in own home and how she sits?
'Crescent shape' across top of nipple imo is definite sign of poor positioning
where the nipple was directed centrally to gape?  Nipple opposite nose when
baby at rest should help.  Is she holding on to baby's head in an attempt to
'control' the baby to stop it coming off because it hurts when baby does this,
or mum doing holding/directing because she is so sore?
Ask what she might be using on her skin, deodorants,shower gels,bath lotions,
wipes, bodyspray, perfumes etc.
Does she use a biological washing powder or fabric conditioner or putting bra
into nappy solution?
Can she put bra or day & night clothing, all family towels,flannels etc. that
comes in direct contact with skin on v hot washes until this completely clears
up.
What about talking about simple hygeine, washing of hands, etc?
What about Dad and other child, could they have low grade thrush infection?
Is she wearing milkproof pads?
Many years ago I did have a case where the Mum and I were sure that she was
allergic to her baby's saliva.
These are just some things that come to my mind, I have not seen any US
literature on how to treat Thrush so guess I might be saying things that you
have already thought about.  Kind regards & keeping fingers crossed, Helen M.
Woodman, National Childbirth Trust Breastfeeding Counsellor, UK.