Talk to Dermatologist on Hair Dandruff And Itching After Color Dying

After getting hair coloring (for grey hairs), my mother's scalp gets itchy at hot times and has contacted dandruff. She has been dying her hair from past 4 years but this problem arised last year. Please suggest any good hair shampoo and oil to avoid dandruff and itchiness. Itching is main concern. Feels like nails are picking at head especially when sweaty. Looking for a good oil & shampoo. No lotions, please.