Since my wife is deathly allergic to natural rubber latex (she's actually been the focus of some medical studies and articles), I understand the frustration and anguish that allergies can result in. However, I'm wondering too how do you know that the knife specifically is what you're allergic to? Are you getting a contact rash or another reaction soon after touching the handle to your body? If so, is it localized to the area of skin that touched the knife, or your hand in general? Is there a possibility of a chemical irritant being involved? Have you tried temporarily covering the handle with something else like some duct or masking tape (assuming you're not allergic to latex) to see if that causes an immediate result?