Hello 
According to you this is 
dandruff so I am writing or advising accordingly :
 Wash hairs with lukewarm water , wet these ,now apply permethrine soap , rinse , leather , keep as such for 2 minutes  , wash with water ( This is in the morning ).
Now for evening .
Wash with lukewarm water as above , apply 
ketoconazole soap for 5 minutes , rinse very well ,  keep it for 3 -4 minutes , wash .
Morning step only for 3 days .
For fourth day use ketoconazole shampoo in the morning , while in the evening soap .
This is for 7 days .
Also take  ketoconazole 200 mg , once in a week for 4 weeks .
This is complete treatment for dandruff .
If other problem like dermamtitis or 
eczema ,then 
consult a dermatologist and get his opinion.