My daughter just started taking topamax (topiramate) for her epilepsy. and i dont know if this on her leg is a rash from it or is her eczema?

Eczema or drug rash: A drug rash is usually fairly widely distributed and either welts or hives or a fine rash that may be slightly raised and red but generally smooth to the touch and fairly symmetrical with both sides of the body equally involved. Eczema tends to give irregular patches that feel dry and scaly and may be somewhat red. If unsure, have a doctor examine it rather that labeling your child "allergic."

Rash on leg: Rash on the leg would not be a typical drug rash. Usually they would cover most of the body. If it looks like eczema she has had before, most likely it is. Follow up with her doctor if it spreads or worsens.

Unknown rash: Likely, determining what the cause of this rash is would take an in person examination. If it appears like her usual eczema rash and responds to the treatments you would normally use, it is probably not due to the medication. Rashes due to medications are not usually localized to one part of the body.

Likely eczema: When medications cause an allergic rash it will not usually be localized as you describe. If it is from topamax, (topiramate) it should spread over the next several days.