Mud Fever in Horses (Pastern Dermatitis) – Complete Guide

What is mud fever in horses?

Mud fever in horses is a bacterial skin infection that affects the lower limbs, usually the pastern and fetlock areas. It’s often seen in wet conditions when constant moisture breaks down the skin. Horses develop painful scabs and cracks which may lead to infection. In some cases, the condition spreads further up the leg.

It’s also called pastern dermatitis and is common in the UK where studies show over 60% of cases occur during the winter months. The problem starts when damp skin cracks and bacteria enter, leading to infection. Without treatment it can cause swelling and lameness, and in severe cases cellulitis may develop. This guide covers what mud fever is, along with its causes, symptoms, treatment, and simple steps to prevent it.

Difference Between Mud Fever and Rain Scald

Mud fever and rain scald are both caused by the same bacteria but appear in different areas. Mud fever occurs on the legs while rain scald affects the back and body where rainwater sits. Both conditions show scabs and hair loss but require similar treatment and management.

Symptoms of Mud Fever in Horses

Symptoms of mud fever in horses include redness, swelling, and skin irritation around the heels and pasterns. These can progress into scabs, hair loss, discharge, and painful skin. In advanced cases, mud fever may cause lameness, loss of appetite, and secondary infections.

Early Symptoms

• Redness and Swelling: The skin on the lower legs, particularly around the pasterns and heels, becomes red and inflamed.

• Matted or Lost Hair: Patches of hair may clump together or fall out, leaving raw and sensitive skin.

• Crusty Patches: Small sores appear and develop into thick scabs, which may crack or ooze.

Progressing Symptoms

• Discharge: White, yellow, or green fluid often collects under the scabs.

• Thickened Skin: The affected area may feel greasy and form ridges or deep cracks.

• Pain and Sensitivity: The horse may resist handling of the leg due to tenderness.

Severe Cases

• Heat: The lower limb feels noticeably hot to the touch.

• Lameness: Pain and swelling can interfere with movement.

• Lethargy and Loss of Appetite: The horse may appear tired and less willing to eat.

• Secondary Infections: Open sores increase the risk of deeper bacterial infections.

How to Spot Mud Fever Before It Gets Worse

Spotting mud fever early is key to stopping it from turning into a painful and stubborn condition. The problem often begins with small changes in the skin on the lower legs that, if ignored, quickly become worse. Regular checks help you notice the warning signs before they progress.

Early Warning Signs

• Redness and swelling: The skin around the pasterns or heels may look inflamed and slightly swollen.

• Clumped or missing hair: Hair can stick together or fall out, exposing sensitive skin.

• Scabs with discharge: Hard scabs may form, often hiding fluid or pus beneath.

• Raw patches: Damaged or broken skin is a clear sign the infection is spreading.

Signs of Progression

• Heat and tenderness: The affected leg feels warmer than usual and may be sore to touch.

• Leg swelling: As the infection worsens, the lower limb can become noticeably puffy.

• Lameness: In severe cases, your horse may resist movement due to pain.

• Thick skin folds: Deep ridges or cracks can appear as the skin reacts to infection.

Areas Commonly Affected

• Usually begins around the heels, pasterns, and fetlocks.

• Can spread upwards to the cannon bone and, in advanced cases, reach the knees or hocks.

Why Acting Early Matters

• Stops escalation: Quick detection helps prevent deeper infections and serious complications.

• Keeps horses comfortable: Early treatment reduces pain and supports faster recovery.

Causes and Risk Factors of Mud Fever in Horses

Mud fever develops when the skin barrier on a horse’s lower legs becomes damaged, allowing bacteria to enter and trigger infection. Wet, muddy, or dirty conditions are the main contributors, but several other factors increase the risk. Understanding these helps prevent repeated outbreaks.

Main Causes of Mud Fever

• Bacterial infection: The most common cause is Dermatophilus congolensis, a bacterium that thrives in wet environments. Once it enters through tiny cuts or softened skin, it causes irritation, scabs, and inflammation.

• Prolonged wet conditions: Standing in mud, wet grass, or damp bedding keeps the skin saturated, softening it and making it more prone to infection.

• Irritated or broken skin: Small nicks from brushing, biting insects, or rubbing boots provide an easy entry point for bacteria.

• Cold and damp weather: Winter and early spring are peak times as horses spend more time in muddy fields and the skin takes longer to dry.

Risk Factors in Horses

• Breeds and colouring: Horses with white socks or pink skin are more prone to mud fever, as their skin is thinner and more sensitive. Breeds with heavy feathering, like Cobs and Shires, are also at risk because feathers trap moisture against the skin.

• Underlying health issues: Horses with Cushing’s disease or compromised immune systems are more likely to develop recurring skin infections, including mud fever.

• Leg mites: Mites can cause itching, scratching, and skin damage, which increases susceptibility to bacterial infection. This is common in heavily feathered breeds.

• Poor stable management: Dirty, damp bedding and unclean stables provide the perfect breeding ground for bacteria and fungi, raising the chances of infection.

• Constant exposure to wet ground: Horses turned out in muddy paddocks or poorly drained fields are at much greater risk.

Why Some Horses Are More Vulnerable

Not every horse will get mud fever in the same conditions. Factors like genetics, immune strength, coat type, and turnout routines all play a role. Horses with strong, healthy skin may resist infection longer, while others show symptoms quickly if their skin barrier is weakened.

Treatment for Mud Fever in Horses

Treating mud fever focuses on keeping the affected legs clean, dry, and free from infection. Mild cases can often be managed at home, but severe or stubborn infections may need veterinary care. Below is a clear step-by-step approach.

1. Prepare the Environment and Clip Hair

• Provide dry conditions: Move the horse to a clean, dry environment to stop further skin damage from mud or damp bedding.

• Clip excess hair: Carefully clip away long or matted hair around the affected area. This allows better cleaning, drying, and access for treatment.

2. Clean the Affected Area

• Soften scabs: Use warm water to gently soften scabs before removal. For painful cases, a vet may recommend sedation to avoid distress.

• Wash gently: Clean the skin with a mild antiseptic solution such as diluted chlorhexidine. Avoid scrubbing too hard, as this can worsen irritation.

• Rinse and dry fully: After washing, rinse thoroughly and dry the leg completely. Damp skin encourages bacterial growth.

3. Apply Topical Treatments

• For mild cases: Apply an antiseptic or antibacterial cream to protect the skin and aid healing. Chlorhexidine-based creams are commonly used.

• For more severe cases: A vet may prescribe stronger creams such as silver sulfadiazine or a topical antibiotic ointment.

• Be consistent: Treatments should be applied daily for at least three weeks, or as advised by your vet. Consistency helps prevent re-infection.

4. Veterinary Care for Severe Cases

• When to call a vet: If your horse shows signs of lameness, swelling, or if the lesions don’t improve after regular home treatment, veterinary help is essential.

• Medication options: A vet may prescribe systemic antibiotics, anti-inflammatory medication, or corticosteroids to control infection and reduce pain.

Prevention of Mud Fever in Horses

Stable & Pasture Management

Good management helps reduce mud fever risks. Rotate grazing fields to avoid heavily poached ground. Provide hard standing areas where horses can stand on drier footing. Keep stable bedding fresh and dry to limit bacterial growth and protect the skin barrier.

Protective Gear and Products

Protective boots and barrier creams can help during turnout. Always apply them to clean, dry legs to prevent trapping bacteria against the skin. Barrier creams stop mud from sticking, while turnout boots give extra defence against wet ground and heavy mud.

Daily Care Tips for Horse Owners

Daily checks are the best way to catch mud fever early. Run your hand down your horse’s legs to feel for heat or scabs. Avoid over-washing and let mud dry before brushing it away. Consistent care during winter lowers the risk of skin infections.

Complications and Related Conditions

Cellulitis and Lymphangitis

Untreated mud fever can lead to serious conditions like cellulitis and lymphangitis. Cellulitis causes hot, swollen, and painful limbs that often need antibiotics and veterinary care. Lymphangitis is a more severe infection of the lymph system and can cause long-term leg swelling if not managed quickly.

Other Equine Skin and Hoof Conditions

Mud fever is not the only skin problem horses face in winter. Thrush, caused by wet and dirty hooves, often appears alongside skin infections. Rain scald and other bacterial issues also increase during cold, damp months, making regular checks vital for horse health.

Final Thoughts on Mud Fever in Horses

Mud fever in horses, or pastern dermatitis, is a common but preventable skin condition. It starts with scabs and sores on the lower legs, often in wet and muddy conditions, and can lead to painful complications if ignored. The key to control is simple: early detection, clean management, and proper veterinary care when needed. With daily checks, dry stables, and protective products, you can reduce the risk and keep your horse comfortable through the winter.