You might be having seborrheic dermatitis
where one gets greasy yellowish dandruff
, itching, redness
over the scalp along with hair fall
. You need to wash your hair with a good anti fungal shampoo at least thrice in a week. Keep your clean and do not oil your hair as it exacerbates the condition. Doxycycline can only help in seborrheic dermatitis when it gets secondarily infected. So don't self prescribe medicines for any medical condition. Take care.