Your daughter has developed contact dermatitis
over the scalp due to the use of hair dye...
It is very important to do a small patch test before using any new hair coloring agent..please take care of it in future.
Also patients who develop contact dermatitis to hair dyes should try using dyes of vegetable origin in future..
Now for the acute attack,firstly avoid using any hair oil..,your child needs to apply topical steroid
lotion containing mometasone over the entire scalp at night ...oral antihistamines like benadryl can be given to decrease the allergic reaction
,,,Use a betadine containing shampoo twice a week and keep hair scalp..sometimes even oral antibiotics
and oral steroids have to be given along in case of severe allergic reaction
So if inspite of the above measures , the irritation perisists, then consult a dermatologist
for proper assessment and management
Hope it helps
Dr Geetika Paul