Let me start by saying how sorry I am that your mother has had to suffer with this. Most people are unaware just how debilitating itching like this (also called pruritus) can be. I am sure that it has also be very hard for you.
Pruritus is actually a fairly common side-effect of cancer or of its treatment. You mention that your mother's physicians don't think that the ovarian cancer is the cause, and the cause may remain unidentified. This doesn't matter, however, and your mother should not be suffering simply because no one can identify the cause of the intense pruritus (the cause is, quite often, not identified anyways). She should be receiving treatment for it in any case.
Treatments can vary. Lotions and topical ointments can help (she's probably tried this), and oral medications can also be some help. These can include antihistamines (histamine is often involved in the horrible itching sensation), sedatives, tranquilizers, and anti-depressants, among others. There are many options.
Applying a cool cloth can also provide some relief, and some find pressure or rubbing the area (gently) can also provide some relief. Some other things that might help include distraction, music therapy, relaxation, and imagery techniques.
So while the cause of this may remain unidentified in the short (or long) term, that does not mean that your mother should continue to suffer.
Call her physician today (or tomorrow if it's too late today). Tell them her pruritus is out-of-control, has been for months, and that she needs some relief immediately. If they won't help you, get a second (or third) opinion until you find someone who will. There is someone out there who will help her find some relief.
Again, I'm sorry that she has had to suffer for so long, and I sincerely hope that both of you find some relief.
Here is a link with some more information, if you're interested:
http://www.cancer.gov/cancertopics/pdq/supportivecare/pruritus/patient
I hope this helps. Please let me know if you have any further questions - I'm more than happy to help. Take care - Dr. Fay
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