Hemosiderin staining usually happens on the lower leg, near the ankles, or on your feet. It’s caused by blood leaking out of the tiny vessels called capillaries. The blood pools under the skin and leave a residue of hemoglobin that settles in the tissue there. Hemoglobin contains iron, which causes the rusty color of the stains.

The haemoglobin from red blood cells is released into your skin tissue and degrades or breaks down into haemosiderin. It is this haemosiderin that causes darker brown or reddish patches of skin above your ankle. The stained skin is very fragile and may break down or, if knocked, fail to heal as usual.

Most people take reddish or brown discoloration on the ankles due to some dermatological problem, but it may be more than that. Discoloration on your legs, ankle, and feet may be a sign of venous disease, venous hypertension, or chronic venous insufficiency that can turn serious if they are not treated timely.

Pigmentation marks on legs can be age spots or dark spots caused by long-time sun exposures. In more serious cases, these brown spots can be the early symptoms of underlying conditions such as cancer or chronic venous insufficiency.