What are the causes of leg ulcers?

Major Causes of Leg Ulcers

Leg ulcers are primarily caused by venous insufficiency (65%), arterial disease (10%), combined venous-arterial disease (10%), and diabetic neuropathy (5%), with venous and arterial causes accounting for approximately 85% of all leg ulcers. 1

Venous Ulcers

Venous ulcers result from chronic venous insufficiency, which is the most common underlying cause of leg ulcers. These develop due to:

• Primary valvular incompetence in superficial veins
• Secondary venous reflux following deep venous thrombosis (DVT)
• Venous obstruction
• Calf muscle pump dysfunction 2

Venous ulcers typically present:

• On the medial aspect of the lower leg, particularly around the ankle
• With associated edema, hyperpigmentation, and lipodermatosclerosis
• Often with minimal pain unless infected

Arterial Ulcers

Peripheral arterial disease (PAD) causes approximately 10% of leg ulcers through:

• Accelerated atherosclerosis, especially common in diabetic patients
• Reduced tissue perfusion leading to ischemic damage 2

Arterial ulcers typically present:

• On the toes, feet, or lateral ankle
• With well-defined, "punched out" appearance
• With severe pain, especially at night or with elevation
• With absent or diminished pedal pulses

Neuropathic Ulcers (Diabetic Foot Ulcers)

Diabetic neuropathy plays a central role in foot ulceration, accounting for approximately 5% of leg ulcers but with significant morbidity. These develop due to:

• Sensory neuropathy leading to loss of protective sensation
• Motor neuropathy causing foot deformities and abnormal biomechanical loading
• Autonomic neuropathy resulting in dry skin and fissuring 2

Neuropathic ulcers typically present:

• On pressure points (metatarsal heads, heel, toes)
• With callus formation around the ulcer
• Often painless despite significant depth
• With intact pulses unless concurrent PAD exists

Mixed Etiology Ulcers

Approximately 10% of leg ulcers have combined venous and arterial components 1. Additionally, many diabetic patients have both neuropathy and vascular disease, resulting in complex "neuro-ischemic" ulcers that are particularly challenging to treat 2.

Less Common Causes

Several less common conditions can cause leg ulcers:

• Vasculitis (inflammation of blood vessels)
• Pyoderma gangrenosum (inflammatory condition)
• Malignancy (skin cancers, lymphoma)
• Infectious causes (bacterial, fungal)
• Hematological disorders (sickle cell disease, thalassemia)
• Autoimmune diseases (rheumatoid arthritis, lupus)
• Trauma with impaired healing
• Medications (hydroxyurea, coumarin necrosis)
• Calciphylaxis in renal insufficiency 1

Risk Factors

Several factors increase the risk of developing leg ulcers:

• Advanced age
• Obesity
• Limited mobility
• Previous DVT or leg injury
• Family history of venous disease
• Smoking
• Diabetes mellitus
• Hypertension
• Hyperlipidemia
• End-stage renal disease 2

Diagnostic Approach

Proper identification of the underlying cause is essential for effective treatment. Key diagnostic elements include:

1. Vascular assessment: Pedal pulse examination, ankle-brachial index (ABI), toe pressures
2. Neurological assessment: Monofilament testing, vibration perception, tactile sensation
3. Wound characteristics: Location, appearance, depth, surrounding tissue
4. Medical history: Diabetes, cardiovascular disease, previous ulcers or surgeries

Prevention and Management

Management must address the underlying pathophysiology:

• Venous ulcers: Compression therapy is the cornerstone of treatment
• Arterial ulcers: Revascularization is often necessary
• Neuropathic ulcers: Pressure offloading and regular debridement
• All ulcers: Wound care, infection control, and addressing systemic factors

Common Pitfalls

1. Failing to identify mixed etiology ulcers
2. Applying compression to arterial ulcers (can worsen ischemia)
3. Inadequate offloading for neuropathic ulcers
4. Overlooking infection
5. Focusing on topical treatments while neglecting underlying causes

Regular assessment by healthcare providers is crucial for patients with risk factors, with frequency determined by risk category, ranging from annual examinations for low-risk patients to evaluations every 1-3 months for high-risk individuals with previous ulceration 2.