Your sister’s symptoms are suggestive of hives or contact 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 rapid
ly and to move around, disappearing in one 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 infections or medications.