My 11 year old has scattered severe bruising all over her legs, ringing in her ears, dizziness, headaches and a red bumpy rash? Chance of leukemia?

Needs to be tested. I would have a CBC (complete blood count) performed today. The bruising makes me think about low platelets. This can happen in leukemia, but is also common in post-infectious situations like itp. Her headaches and ringing in her ears could be viral infection, or even bacterial infection. However, headaches can be seen with anemia. A simple blood test will be very helpful. Good luck.
Get blood work. Statistically it is a low possibility, but I think it warrants having her seen by a doctor who can do some screening labs. I would not wait. Once these initially labs are completed, it will be easier to know if leukemia is a more likely possibility or some other condition. I hope she feels better soon.

Related Questions

My 11 year old has had knee and hip joint pain for a year now. Her bruising is getting worse, she gets dizziness, ringing in her ears, headaches and a rash. What should ido?

See your doctor. You should make an appointment for your 11 year old with a pediatrician very soon as this could be more serious than just knee and hip pain.
Evaluation a must. It is necessary to be evaluated immediately. Please do not wait until tomorrow.
See rheumatologist. These long standing problems should be evaluated by a pediatric rheumatologist. They will be able to do a good physical exam and some screening blood tests to help figure out what is going with your daughter. You could start with your pediatrician if they are comfortable ordering the initial testing, but they may choose to refer.