Hello,
Welcome to Healthcaremagic.
From your query i understood that your mother have Chronic non healing ulcer in ankle.
It sounds to be not a skin problem, but some vascular disease
Some common causes are Diabetic ulcer, Vascular diseases like
varicose veins, peripheral vaso occlusive disease,
vasculitis etc..
She need to be investigated for these.
Fasting and postprandial blood sugar.
Doppler study of lower limb.
If it is due to
diabetes, it can easily controlled by
insulin injections.
If it is due varicose veins, compression bandage can be used.
For infection, antibiotics are used.
If all the above diagnosis are ruled out, better take
biopsy of wound for malignancy.
Hope this helps.
Take care.
If any doubt,Kindly reply.
Regards,
Dr.Manjeth