I would highly recommend that you get in to see your primary care doctor
again or even a dermatologist
if you are not finding adequate relief for your dandruff. Dandruff is a form of seborrheic dermatitis, in which the skin of the scalp becomes inflamed and itchy often with scaly patches or flaking areas. Although dandruff is very common and generally easily treated, sometimes more severe seborrheic dermatitis requires additional medications that a dermatologist would prescribe for you (such as antifungal medications and steroid creams).
Generally speaking diet is not related to dandruff severity. There is a caveat here, however, because if you have multiple food allergies and eczema
, then you could have eczema of the scalp rather than seborrheic dermatitis. Eczema of the scalp could, at least theoretically, be worsened by consuming foods that you have an allergic sensitivity to.
Start by getting in to see either your doctor or a dermatologist. They will be able to make an assessment of how severe your dandruff is and what should be done next. Make sure you let them know that you have already tried many of the common treatments without much effect. Ideally, with new medications you should notice significant reduction in both flaking and itching.