Brown stains on the feet and ankles is often a sign of severe varicose veins or severe "hidden varicose veins". These are both caused by venous reflux. Severe varicose veins - bulging or hidden - can cause clots in the veins. These clots are initially red, hot and tender. This is called "phlebitis" or "superficial venous thrombophlebitis".

Brown Stains on Feet from Superficial Thrombophlebitis - Phlebitis - CEAP C4 - Diagnosed at The Whiteley Clinic

Phlebitis should always be referred to a specialist vein clinic for a duplex ultrasound. This is to check the clot hasn't gone into the deep veins. (see: https://thewhiteleyclinic.co.uk/news/reading-this-might-save-your-life-phlebitis/) However, if it is missed or not treated, then the old clot can turn the skin brown. This is due to the iron being released from the blood and staining the skin These brown stains on feet and ankles is "haemosiderin deposition".

PPG of Brown Stains on Feet from Superficial Thrombophlebitis - Phlebitis - CEAP C4

Brown stains on feet or ankles - A sign treatment is needed

When any brown stains appear on the foot or ankle then the condition needs investigation and treatment. This is true even if varicose veins cannot be seen on the surface. Brown stains on the foot or ankle (Haemosiderin), is a form of skin damage due to the venous reflux of varicose veins. NICE, (the National Institute of Health and Clinical Excellence) has published guidelines that recommend referral to a "vascular service" with this condition. (see: https://www.nice.org.uk/guidance/cg168/chapter/1-recommendations#referral-to-a-vascular-service-2). The Whiteley Clinic fulfills the definition of a vascular service according to NICE. However, a doctor doing their own scan in their own room does not! Anyone with brown stains on feet or ankles should seek help from a specialist vein clinic to prevent the condition both recurring and the damage worsening. Links: Phlebitis: https://thewhiteleyclinic.co.uk/conditions/phlebitis/ PPG: https://thewhiteleyclinic.co.uk/examination/photoplethysmography-ppg/ NICE Recommendations: https://www.nice.org.uk/guidance/cg168/chapter/1-recommendations#referral-to-a-vascular-service-2