Hello,
As the hives have been there for such a long time (1 year),then
it can be chronic hives.Mostly
it is idiopathic i.e no cause
is there,but sometimes it is essential to rule out the presence of serious illnesses of which recurring hives can be a symptom. Examples are autoimmune diseases,hepatitis, hyperthyroidism, lymphomas, collagen vascular diseases, and cancers of the rectum, kidneys and gastrointestinal tract.