Hello,
It can be due to vascular problems causing telangiectasia skin or schamberg’s disease. Schamberg's disease is a rare disease and is a chronic discoloration of the skin which usually affects the legs . It can be found at any age and in any gender but males are more commonly effected. It is a disease in which there is leaky blood vessel walls which allow red blood cells to slip through into the skin. Unfortunately there is no cure for this disease except steroid creams which are available by prescription. My sincere advice would be to consult a dermatologist.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.
Looks like schamberg's disease, a benign condition(Not serious). No specific treatment. Do consult your doc.