When you have mental stress or there is impaired cognitive functioning from a chemical imbalance in the body, hives can be triggered. In general, stress can cause a variety of health issues.
If there is disorientation, confusion, and memory loss to a large degree, this could indicate that not enough blood and oxygen is reaching the brain due to infection or an underlying disease.
Scombroid poisoning is an illness that results from eating spoiled fish. It causes unpleasant symptoms that normally begin an hour after ingestion. In severe cases, the poisoning can cause death.
Classic symptoms of scombroid include nausea, vomiting, cramps, and diarrhea. These may be very mild, however. Other symptoms include flushing, a racing heart, itching, and hives.