Vet Tips 2025: Understanding Cutaneous Lymphangitis in Horses 🐴🦵

By Dr Duncan Houston BVSc

If your horse has a swollen leg—especially below the hock—you may be dealing with a condition called cutaneous lymphangitis. It’s more than just “big leg” or a minor infection. Without early intervention, it can lead to permanent scarring, lameness, and even long-term discomfort. 🧊🩺

What Is Cutaneous Lymphangitis? 🧠🦠

Cutaneous lymphangitis is inflammation of the lymphatic vessels in the skin, typically of the lower limbs. These vessels help drain lymph fluid that collects during circulation. When these vessels become blocked, leaky, or inflamed, swelling occurs—usually in one leg. 🦵

How the Lymphatic System Works 🧬💧

The lymphatic system supports your horse’s immune function and fluid balance. It includes:

• 🔬 Tiny lymph vessels under the skin
• 🧪 Lymph nodes that filter out bacteria, viruses, and toxins
• 🧠 Organs like the spleen and thymus for immune defense

When lymph flow is disrupted—whether by infection, injury, or fly bites—it causes fluid buildup and visible swelling. 🚨

What Causes Cutaneous Lymphangitis? 🕵️‍♂️

• 🐛 Biting flies transmitting bacteria
• 🧫 Contaminated wounds or lacerations on the lower limbs
• 💩 Poor hygiene or dirty stalls increasing skin infection risk

While often considered a hygiene-related disease, lymphangitis can occur in otherwise clean environments—especially if biting flies or trauma are involved. 🦟

Recognizing the Symptoms 👀🐴

Early recognition is crucial. Signs include:

• 🦵 Sudden leg swelling (usually one leg)
• 🧱 Firmness or nodules under the skin
• 💥 Hot, painful swelling with lameness
• 🧫 Abscesses or draining tracts on the skin
• 💤 General lethargy or reluctance to walk

If left untreated, swelling can become permanent due to scar tissue formation. ⏳

How Is It Diagnosed? 🔍🧪

A veterinary exam is required to confirm the diagnosis. Your vet may:

• 🩺 Perform a physical exam of the affected limb
• 🧬 Take samples from skin lesions to culture bacteria or fungi
• 📊 Rule out other causes of limb swelling (like cellulitis or tendon injury)

Early diagnosis = faster recovery. Always call your vet if you notice swelling in one leg. 📞

How Is Cutaneous Lymphangitis Treated? 💉🛠️

Prompt, aggressive treatment is key. This usually includes:

1. Antibiotics 💊

Systemic antibiotics are used to target the underlying infection. Long courses may be required for deep skin involvement.

2. Anti-inflammatories 🔥

NSAIDs (non-steroidal anti-inflammatory drugs) reduce pain and inflammation.

3. Cold Therapy 🧊

Cold hosing or ice boots help reduce swelling and promote comfort.

4. Topical Wound Care 🧼

Abscessed nodules may need draining and topical antiseptics. Your vet will choose products based on the type of organism found.

5. Movement and Controlled Exercise 🚶‍♂️

Light, controlled movement helps stimulate lymph flow—stall rest without activity can worsen the condition.

⚠️ If treatment is delayed, scarring and irreversible swelling may occur.

What’s the Prognosis? 🌈🔮

Most horses respond well to early treatment. However, if diagnosis is delayed or treatment is inconsistent, complications may include:

• 🧱 Fibrosis (hardening of the tissues)
• 💥 Permanent swelling of the leg
• 💊 Recurring infections

In severe cases, horses may experience ongoing lameness or reduced performance capacity. ⚠️

Prevention Strategies 🧽🛡️

While not all cases are preventable, these tips can help:

• 🧼 Keep stalls clean and dry
• 🦟 Use fly sprays, fly boots, and repellents during peak insect seasons
• 🔍 Check lower limbs daily for cuts, swelling, or early lesions
• 🚪 Avoid muddy paddocks or unsanitary turnout areas

Quick action on minor wounds may prevent lymphangitis from taking hold. ⏱️

Need Help With a Swollen Leg Case? Ask A Vet 📱🐴

Unsure if your horse’s swollen leg is cutaneous lymphangitis or something more? Speak with a certified equine veterinarian now at Ask A Vet.

Download the Ask A Vet app for instant guidance on leg swelling, wound care, and post-treatment recovery plans tailored to your horse’s history. 🐎

Final Thoughts: Don’t Delay With “Big Leg” 🛑🐴

Cutaneous lymphangitis is treatable, but time matters. Swelling, nodules, and lameness should never be ignored. Call your vet early, treat aggressively, and monitor closely for recurrence. 🧠

Need support? Visit Ask A Vet for expert help managing leg swelling and other equine health concerns—anytime. 🐴🩺