@SteamLouis-- Have you seen your doctor about this? I'm sure that your doctor will give the best advice.
I'm not an expert but I think it's possible for food allergies to cause skin bumps and itching on the hands. Usually, food allergies show symptoms on the face, lips or the tongue. Allergies can cause lips and face to swell and itch. It can also cause the tongue and throat to swell which is very dangerous and can lead to death through anaphylaxis.
Symptoms on skin like skin on the hands is most often due to contact dermatitis. So you would get these issues after touching something that you are allergic too. But someone once told me that they get a weird, flaky, itchy rash on their hands after eating eggs. If that's true, then it's also possible to get an itchy rash on the hands after eating seafood that you are allergic to.
Like I said, see your doctor and get the necessary allergy tests to get to the bottom of this.