Typical antihistamines do not really work on food allergies or food induced histamine.

The H2 blockers work better on food issues. This is Zantac, Pepcid and Tagamet. Allergists use these for food reactions.

Another thing that works on food problems is Sod. Bicarbonate.
AlkaSeltzer Gold or the plain tablets. This blocks histamine receptors and can reduce chronic pain. No more than 3 times a day. But avoiding the triggers is the best way to do this rather than supplements after the fact..

If you are engaging in some exercise to stress your hand, like boxing, making fists, or grasping some tool with stressful force, that has to stop. Some yoga positions may stress the hand and palms.. Are you using some squeeze balls or hand energizers?
If so stop them.

Baby yourself for at least a month. See if things change.