This is Dr. David
I am a radiation oncology doctor
I give radiation to many many many woman.
usually eczema on the scalp is not a side effect of radiation to the breast
if you are taking anti-estrogen hormone therapy after your breast radiation like tamoxifen or arimidex or femera, these can sometimes drop your estrogen levels and cause dry skin and this can sometimes cause eczema.
also you need your thyroid hormone levels checked as well.
low thyroid hormones can cause skin issues as well.
are you taking tamoxifen or arimidex?
are you having dry skin?
make sure your TSH level is between 0.3 and 3.0
radiation really only causes side effects in the breast and skin of the area getting radiation.
it usually does not cause side effects all over your body