Haemosiderin is a protein compound that stores iron in your tissues, which accumulates under your skin. As a result, you may notice yellow, brown, or even a bruise-like staining appearance, often found on the lower leg, sometimes covering the space between your knee and ankle.
The major cause of these brown marks is chronic inflammation. This is most like to be due to:
When brown marks appear on the skin at the ankle due to varicose veins, or “hidden varicose veins,” this is classified as CEAP C4. The brown marks (Haemosiderin) occur because of the venous blood refluxing the wrong way down the veins. This occurs due to the one-way valves failing in the veins. The appearance of brown marks at the ankles is a sign of severe venous disease. If the underlying varicose veins, or “hidden varicose veins,” are not treated, the skin damage will continue. This is eventually lead to a venous leg ulcer.