Allergies are a common cause of hives since an allergic reaction can trigger the immune system response that results in trapped fluid beneath the skin.An allergic reaction can occur due to something you ingested or were exposed to through the air.hoto Credit pollen image by asb from Fotolia.com. Allergies are a common cause of hives since an allergic reaction can trigger the immune system response that results in trapped fluid beneath the skin. An allergic reaction can occur due to something you ingested or were exposed to through the air.
The median nerve, which runs through the arm and hand, can cause swelling pain and numbness if injured. Ulnar nerve injury Damage to the ulnar nerve causes swelling, pain and numbness in the forearm, hand, and ring and little fingers.
1 This disruption of nerve function can make your hands/arms fall asleep until blood flow improves.  Ulnar Nerve Entrapment. When your ulnar nerve, which runs from the neck down to the arm, gets compressed, it can make the hand/arm become numb.