Yes, Linda Smith, I agree that nipple pain can lead to shut down of blood
flow to nipple, ie vasospasm.
Laureen Lawlor-Smith, GP/LC in Adelaide, and her sister have written
something on treating vasospasm with nifedipine; I don't know if it has been
published yet.
I saw a woman today with a crater in one nipple: 2 X 2.5cm in size!!!! She
has been continuing to feed (controlling pain with aspirin on nipple - not
to be recommended!), and not helped by lanolin  and antibiotic. I have said
that she had better stop feeding and express by hand. I've called a wound
management nurse to see if she can help. I'll let you know if she has any
brilliant ideas.
Lisa Amir
GP/LC, Melbourne, Australia