Your sister’s symptoms are suggestive of hives or con
tact dermatitis. Hives (medically known as urticaria) are red, itchy
, raised areas of skin that appear in varying shapes and sizes. They have a tendency to change size rapidly and to move around, disappearing in on
e place and reappearing in other places, often in a matter of hours.
Many cases of hives are "idiopathic," meaning no cause is known. Others may be triggered by viral infection
s or medication