What Is The Itchy Raised Area On The Heel Of Hand?

On the heel of my hand I have an itchy, raised area that has been there since September, and I thought when I first noticed it that I had been bitten by an insect. The itching is intense and it looks like it is getting bigger. It happened after I washed the dirt off of a cantelope from my mother-in-law's garden. She has cats, and I don't know if it could be a hook worm or toxoplasmosis or something like some sort of parasite.