Hello,
Seborrheic dermatitis is a common skin condition that causes flaky,dry, white to yellowish scales to form on oily areas esp under the nose or anywhere on face. Topical antifungals and mild steroids are the usual treatment and combination of the two can be used to treat stubborn patches. Oral antifungal drugs and immunomodulators such as tacrolimus and pimecrolimus are used in very severe cases. Oral antifungals are not without side effects and should be used with caution after consulting a dermatologist.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.
I don't know if this will help you, but it helped my husband with the same problem. Maybe try a gluten free diet (gluten is in wheat, barley, rye and oats). You can look the diet up on the computer. It's not everyone's cure, but maybe it will help you. You have to stick with the diet 100% to see if it gives you relief. Give it a try for 3 months and see if things get better. You will need a gluten free vitamin (Nature Made brand). Good luck!