At what circumstances does black circular patches occur in the leg?

Hello,

Welcome to icliniq.com.

I understand your concern.

The most common cause is old age. Small vessels become fragile and rupture in old age, leading to blackish bruises. It is common in lower limbs but can occur anywhere on the skin. Another cause is medicines. If a person is using drugs called steroids or anticoagulants, or anti-platelets, then such bruises can occur. Another cause is trauma. Only minor injuries can cause bruises in old age, as vessels are fragile. Rare causes are some disorders of the coagulation system, platelet function, etc. Is she suffering from any chronic disease or using some medicines? Please give a complete history and send pictures of bruises so I may guide you properly.

I hope this information will help you.

Thanks.