It is difficult to be sure about your niece's problem without being able to see her. She may have a condition called juvenile rheumatoid arthritis. She must be seen by a paediatrician as soon as possible.
The information provided does not constitute a diagnosis of your condition. You should consult a medical practitioner or other appropriate health care professional for a physical exmanication, diagnosis and formal
advice. Health24 and the expert accept no responsibility or liability for any damage or personal harm you may suffer resulting from making use of this content.