My 14yrs old daughter has itchy rashes all over her ankle, what could it be?

Many things: Localized itchy rashes are usually do to dermatitis (from plant or chemical), insect bites (such as fleas) or eczema. A description of the rash would be helpful. In the interim, itchy skin rashes not associated with other symptoms usually respond well to topical steroids such as 1% hydrocortisone.

Eczema: Eczema is a possibility. Local allergic reaction due to contact with plants , insects or chemicals may be another reason your doctor may need to see the rash for proper diagnosis and treatment

Contact?: LIkely a contact allergy from her socks or shoes. On the other hand, flea bites may also be concentrated at the ankle areas and you should make sure your pets don't have fleas if you happen to have pets. In the meanwhile , try cortisone cream.