Inflammatory Breast Cancer Early Signs?

My sister showed me an area on her breast that is large and red looks like some sort of rash. She woke up one morning and noticed it and she said it is bigger now than it was originally. She also says she feels constant burning and heat sensation in her left breast. The pain is only getting worst. I think this could be a sign of something serious.
I am really scared and worried for her.
Could this be Inflammatory Breast Cancer? I told her she should go and see a doctor. What are the early signs of Inflammatory Breast Cancer?

I know how scared you must be feeling. Have your docs biopsied the rashy area?
Anyway I found some information for you:

Early signs and symptoms of inflammatory breast cancer

Inflammatory breast cancer grows in sheets or nests under the skin, rather than lumps. IBC Support Group states that this cancer "blocks the lymph vessels in the breast and skin." This blockage causes changes in the skin of the breast and leads to many of the other signs and symptoms of IBC.

According to IBC Support and the Mayo Clinic, signs and symptoms of IBC may include rash, discoloration, bruising and thickening or dimpling of the breast skin. The breast may swell, as may lymph nodes under the arm or above or below the collarbone. The breast may be itchy, painful or both. Any changes in the nipple, including flattening, inversion or a discharge, require immediate evaluation.