Skin irritation from Victorinox Fibrox handle All of my favourite knives are stamped Victorinox with black fibrox handles... I find the shape and grip of these knives, coupled with the thin and flexible stamped blades, are ideal for processing any food that doesn’t require a cleaver. 

But... I have eczema on my hands, most pronounced in my (dominant) right palm. I apply a very strong corticosteroid to my hands, once weekly, to keep the disease in check. 

I don’t know why this took me so long to make the connection, but the worst rash spots are on the two contact points with the knife handle; one spot on the the heel, and another on the pad between my index and middle fingers. So to test, about 3-4 days ago I set aside all my comfortable knives and am using (mostly my wife’s) forged blades with hardwood or resin handles. And... my rash is going away! Today it is time for my weekly medicine, and the hands look pretty much like the morning after treatment. 

It only took me 30 years to put 2 and 2 together....

My question is: Is this material known for causing allergic reactions or other kinds of dermatitis problem? A google search comes up with nothing, which surprises me. 

I have a known latex intolerance (but the symptoms are generally different)
Black Fibrox is a trademarked brand name for Thermoplastic Elastomers, or TPEs.  This is a common plastic substance used to produce "grippy" plastics that feel rubberized, for a variety of applications.

Thing is, TPEs were largely invented as an allergy-free alternative to latex.  Studies have, to date, not turned up any naturally occuring TPE allergies in test subjects.  So you may be the first patient with a TPE allergy!  Lucky you.

To verify this, do you have any wearable electronics?  Items like the Fitbit and various smartwatches frequently use TPEs as band/covering material.  If you have one of these, and you are allergic to TPEs, you should be reacting to it as well.  Or go to your dermatologist, now that you know the substance you think you are reacting to, he can do targeted tests.

I can think of two short-term solutions for your knives.  One is to sell them any buy the versions with "rosewood" handles, which I believe are non-TPE.  The second would be to coat the TPE handles in something durable, like silicone.