Skin ulcer on feet: types, causes, and when to seek specialist help

A skin ulcer on the foot is an open wound where the skin has broken down and the underlying tissue is exposed. Unlike a cut or scrape, foot ulcers often resist healing — they can persist for weeks or months, expand gradually, and lead to serious complications including infection, bone damage, and in severe cases, amputation. This article covers the main types, their causes, and when to seek specialist help. It is general education, not medical advice — always consult a licensed physician about your own situation.

Five types of skin ulcers that affect the feet

Not all foot ulcers are the same. Identifying the type is the first step toward effective treatment, because each type has a different underlying cause and requires a different treatment approach.

Venous ulcers

Venous ulcers develop when the veins in the legs cannot efficiently return blood to the heart. Blood pools in the lower legs, causing pressure that eventually breaks down the skin. They are the most common type of leg ulcer overall, though they more frequently affect the lower leg and ankle than the foot itself.

• Typical location — inner ankle (medial malleolus), sometimes the outer ankle or lower shin
• Appearance — shallow, irregularly shaped, with a red or yellowish wound bed. Surrounding skin is often discolored (brown or reddish), thickened, and may be weepy or swollen
• Pain level — usually mild to moderate, relieved by elevating the leg
• Key risk factors — varicose veins, deep vein thrombosis (DVT) history, obesity, prolonged standing, previous leg injury

Treatment centers on compression therapy (graduated compression bandages or stockings) to counteract the venous pressure. Most venous ulcers heal within 3–6 months with consistent compression and wound care.

Arterial ulcers

Arterial ulcers (also called ischemic ulcers) form when blood flow to the foot is reduced by narrowed or blocked arteries — a condition called peripheral arterial disease (PAD). Without adequate blood supply, the tissue starves and breaks down.

• Typical location — toes, between toes, outer ankle, or bony prominences of the foot. Often on areas furthest from the heart
• Appearance — round, well-defined edges with a "punched out" look. Wound bed may be pale, grey, or black (necrotic). Surrounding skin is shiny, thin, and hairless
• Pain level — often severe, especially at night or when legs are elevated. Walking may temporarily improve pain (the opposite of venous ulcers)
• Key risk factors — smoking, diabetes, high blood pressure, high cholesterol, age over 50

Treatment requires restoring blood flow — often through angioplasty, stenting, or bypass surgery. Without revascularization, arterial ulcers rarely heal and carry a high amputation risk.

Neuropathic ulcers (diabetic foot ulcers)

Neuropathic ulcers are the most common type of foot ulcer, affecting approximately 15–25% of people with diabetes during their lifetime. They develop because diabetic nerve damage (neuropathy) eliminates the protective sensation that normally alerts a person to injury, pressure, or friction. The foot sustains repeated micro-injuries during walking that go unfelt and unaddressed.

• Typical location — sole of the foot (plantar surface), especially under the metatarsal heads (ball of the foot), the heel, and the tips of toes. These are the highest-pressure areas during walking
• Appearance — round, callused edges. Wound bed is usually pink or red. Often surrounded by a ring of thick callus. May have drainage but minimal bleeding
• Pain level — typically painless, which is the most dangerous feature. Patients often walk on an open wound for weeks without knowing it exists
• Key risk factors — diabetes (types 1 and 2), peripheral neuropathy, foot deformity, history of previous ulcers, poor glycemic control

Diabetic foot ulcers are covered in much greater depth below because they represent the highest-risk category for complications. For a detailed guide to symptoms and stages, see our article on diabetic foot sores: symptoms, stages, and when to seek help.

Pressure ulcers

Pressure ulcers on feet develop when sustained pressure compresses the tissue between a bony prominence and an external surface (shoe, mattress, cast, or wheelchair footrest). The compressed tissue loses blood supply and begins to die.

• Typical location — heels (most common on feet), sides of toes, bunion area, any bony point where a shoe or surface creates sustained pressure
• Appearance — ranges from a non-blanchable red area (stage 1) to full-thickness skin loss exposing bone or tendon (stage 4). May appear as a blood blister or develop a dark eschar (scab-like covering)
• Pain level — variable. May be painful in patients with normal sensation, or painless in patients with neuropathy
• Key risk factors — immobility (bed-bound or wheelchair-bound), diabetes with neuropathy, poor nutrition, aging skin, peripheral vascular disease

Treatment focuses on removing the pressure source (offloading), optimizing nutrition, and wound care. Heel pressure ulcers can be stubborn because the heel has relatively little tissue between the skin surface and the calcaneus bone.

Traumatic ulcers

Traumatic ulcers result from a specific injury — a cut, burn, blister, foreign body, or frostbite — that fails to heal normally. In a person with healthy circulation and sensation, most traumatic wounds heal within 2–3 weeks. When they do not, an underlying condition is almost always present.

• Typical location — anywhere on the foot, determined by the site of injury
• Appearance — variable, depending on the original injury. A non-healing blister, a stubborn cut, or a burn that will not close
• Pain level — usually painful initially, though pain may diminish as the wound becomes chronic

A traumatic wound that has not healed after 2–3 weeks should be evaluated for underlying diabetes, vascular disease, or immune compromise. In many cases, a "traumatic" ulcer is actually the first sign of an undiagnosed systemic condition.

How to tell the types apart

While only a clinician can make a definitive diagnosis, several features help distinguish the types:

• Location on the foot — ankle = likely venous; sole or ball of foot = likely neuropathic/diabetic; toes = likely arterial or diabetic; heel = likely pressure
• Pain behavior — worse when elevated = arterial; better when elevated = venous; absent = neuropathic (dangerous sign)
• Wound edges — punched-out and clean = arterial; callused ring = neuropathic; irregular and shallow = venous
• Surrounding skin — brown discoloration and swelling = venous; shiny, pale, hairless = arterial; thick callus = neuropathic
• Pulses — weak or absent foot pulses suggest arterial disease; strong pulses with a numb foot suggest neuropathy

Many patients have more than one contributing factor. A person with diabetes may have both neuropathy AND peripheral arterial disease, producing a "neuro-ischemic" ulcer that combines features of both types. These mixed-cause ulcers are the most difficult to treat and the most likely to result in amputation.

Why diabetic foot ulcers deserve special attention

Among all types of foot ulcers, diabetic foot ulcers (DFUs) carry the highest risk of serious complications. The statistics are sobering:

• 15–25% of people with diabetes will develop a foot ulcer in their lifetime
• DFUs precede approximately 85% of all diabetes-related amputations
• The 5-year mortality rate after a diabetes-related amputation exceeds 50% — higher than many cancers
• Recurrence rates are approximately 42% within 1 year and 65% within 5 years after healing

The danger of DFUs lies in the combination of three factors that reinforce each other:

• Neuropathy masks pain — injuries accumulate undetected, turning small wounds into large ones
• Peripheral arterial disease starves the wound — reduced blood flow means less oxygen and fewer immune cells reach the wound
• Hyperglycemia impairs healing — elevated blood sugar slows every phase of the wound healing process and feeds bacterial growth

This "triple threat" means that diabetic foot ulcers progress faster, heal slower, and resist standard treatment more stubbornly than any other type of foot ulcer.

Stages of diabetic foot ulcer progression

Clinicians commonly use the Wagner grading system to describe severity:

• Grade 0 — intact skin with risk factors (callus, deformity, neuropathy). No open wound yet
• Grade 1 — superficial ulcer. Skin has broken open but the wound does not reach deeper structures
• Grade 2 — deep ulcer extending to tendon, joint capsule, or bone. No abscess or osteomyelitis
• Grade 3 — deep ulcer with abscess, osteomyelitis (bone infection), or joint sepsis
• Grade 4 — localized gangrene (forefoot or heel). Dead tissue is present but limited to part of the foot
• Grade 5 — extensive gangrene involving the entire foot. Emergency intervention required

The critical insight: treatment options narrow dramatically at each stage. At Grade 1, nearly every option is available. By Grade 4–5, the question shifts from "how to heal the wound" to "how much of the foot can be saved." For a detailed guide to Wagner grading, see our article on Wagner classification for diabetic foot.

Treatment approaches by ulcer type

Effective treatment depends on correctly identifying the type and addressing the root cause — not just treating the wound surface.

Venous ulcers

• Compression therapy (the cornerstone — bandages, stockings, or pneumatic devices)
• Leg elevation when resting
• Moist wound dressings
• Exercise and weight management
• Surgical intervention for severe varicose veins in selected cases

Arterial ulcers

• Revascularization (angioplasty, stenting, or bypass surgery) to restore blood flow
• Careful wound care — compression must be AVOIDED as it further reduces blood supply
• Smoking cessation (critical — smoking is the single largest modifiable risk factor)
• Management of cardiovascular risk factors

Diabetic foot ulcers

• Offloading — total contact casting or specialized footwear to eliminate pressure on the wound
• Debridement — removal of dead tissue and callus to promote healing
• Infection management — culture-guided antibiotics for infected wounds
• Vascular assessment — up to 50% of non-healing DFUs have an undiagnosed vascular component
• Advanced wound therapies — negative-pressure wound therapy, bioengineered skin substitutes, biological debridement
• Specialist surgical options — for wounds classified as "no-option" after standard approaches, techniques like Tibial Cortex Transverse Transport (TCT) have shown wound healing rates exceeding 96% in clinical studies

The most important factor in DFU treatment is early specialist involvement. Multidisciplinary diabetic foot teams that combine vascular surgery, orthopedics, wound care, and endocrinology consistently achieve better outcomes than single-specialty treatment. For a complete guide to limb-saving treatment options, see our article on alternatives to diabetic foot amputation.

Pressure ulcers

• Complete pressure relief from the affected area
• Specialized heel-offloading devices or therapeutic mattresses
• Nutritional optimization (protein, calories, vitamins C and A, zinc)
• Staged wound care — debridement, moist dressings, infection control

When to seek specialist help

Any foot ulcer that fails to improve deserves professional evaluation. Seek specialist help if:

• A wound has not improved after 2 weeks of home care
• You have diabetes and notice ANY break in the skin of your feet — no matter how small
• The wound is expanding, deepening, or developing a foul odor
• You see black, grey, or dark tissue in or around the wound
• The surrounding skin is hot, red, swollen, or there are red streaks extending from the wound
• You have fever, chills, or feel generally unwell
• You have been told amputation is necessary and want a second opinion

For diabetic foot ulcers specifically, specialist centers with multidisciplinary diabetic foot teams offer the widest range of treatment options. Chinese specialist centers are increasingly recognized for advanced limb salvage techniques, including TCT surgery, at a fraction of the cost of equivalent procedures in the US or Europe.

DFU Care China provides free remote assessments for patients with non-healing foot ulcers. Share your wound photos and medical records via WhatsApp for an honest specialist evaluation of your treatment options.

This article is for educational purposes. Every patient's situation is different. The treatment options described here may not apply to all patients. Always consult a qualified medical professional about your specific situation.