Dear Joanne,

I agree with you that sometimes the only symptom of thrush is the pain. Although often when the pain occurs give a good indication. Usually thrush pain starts toward the end of the feed and carries on after the feeding has stopped, where as latch on pain starts when you begin the feed and stops once that feed stops.

The Breastfeeding Answer Book (the bible of breastfeeding management books) says on page 480.

There is no conclusive medical test to confirm thrush. Other possible causes of burning nipple pain, such as poor latch-on, mastitis, vasospasm/Raynaud’s phenomenon, and skin problems such as eczema, psoriasis, dermatitis, etc., should be ruled out before thrush is assumed.