Why does my skin on my legs look mottled and purplish?
Source: Mayo Clinic: Lawrence E. Gibson, M.D.
Livedo reticularis is thought to be due to spasms of the blood vessels or an abnormality of the circulation near the skin surface. It makes the skin, usually on the legs, look mottled and purplish, in sort of a netlike pattern with distinct borders. Sometimes livedo reticularis is simply the result of being chilled. But it may be a symptom of a serious underlying condition, such as vascular disease. And it may occur as a side effect of certain medications.
When to see a doctor
The condition usually clears up without treatment. See your doctor in the following situations:
The discolored, mottled skin doesn't go away with warming
The discolored, mottled skin is accompanied by other signs and symptoms that concern you
Painful nodules develop in the affected skin
Ulcers develop in the affected skin
You also have peripheral vascular diseases.
This is a new development and you are known to have lupus erythematosus or other connective tissue diseases.