The fact is that
the allergic component of cats is actually not the fur itself but the dander, or more specifically the protein that is found in the cat's shedded skin cells and saliva.
The etiology of eosinophilic oral diseases in dogs and cats may vary, but
an allergic component seems to play a role in most cases.
Also, inflammatory bowel disease, which can progress to pancreatitis and triaditis, is thought to have
an allergic component.
Although pets initially respond to treatment,
the allergic component remains in the body for a few days and despite medication the pet may experience return of hives and facial swelling, although less severe, over the following 48 - 72 hours.