Toddler with cradle cap

So, my girl had minimal cradle cap as a baby, went away easily with a silicone sponge.

She's now 19 months and her entire scalp is covered. She already has EXTREMELY thin and fine midneck length hair. I was combing her tonight and a big piece flaked up so I lifted it out of her hair and a huge chunk of hair came out.

How can I treat her without making her go bald?

She gets a bath every other day or every third day if we don't leave the house.