Hi, welcome to healthcare magic
The high IgE does suggest the presence of allergies. More specific allergy tests
can be done to identify exactly what your sister is reacting to.
Allergy tested can be done by skin testing or blood tests can be done to check for the response to a variety of allergens.
In skin testing a small amount of the allergen is placed on or below the skin to see if a reaction develops.
The blood tests checks for the presence of certain antibodies
in the blood .Antibodies are found if your body has responded to a substance, in this case an allergen. It also checks the intensity of the response.
Allergy tests can check for problems with foods, dust, animals, grasses just to name only a few.
Your sister should speak to her doctor about where she can have the test done, once the specific allergen is identified then she can determine whether it can be avoided.
I hope this information is helpful to you