Scratches Mud Fever

Scratches, also called mud fever or pastern dermatitis, is one of the most common skin conditions horse owners encounter, yet it's often misunderstood and mismanaged until it becomes serious. This infection of the skin in the pastern region—the area between the fetlock and the hoof—typically develops when moisture, dirt, and bacteria create the perfect storm for inflammation. What starts as minor irritation can escalate into painful lesions, scabbing, and swelling that affects your horse's movement and comfort if you don't catch it early.

The condition earned its nickname "mud fever" because wet, muddy conditions are the primary culprit, but scratches can develop anywhere moisture sits on the pastern region for extended periods. Horses kept in wet paddocks, poorly drained stalls, or those spending hours in dewy grass are at higher risk, but any horse can develop it if conditions align. The good news is that scratches is manageable and often preventable once you understand what causes it and how to recognize the early warning signs before things get out of hand.

Why understanding scratches matters goes beyond comfort—it's about preventing secondary infections that can turn a minor skin issue into something requiring serious veterinary intervention. A horse with scratches hobbles around with pain in their hooves, resists movement, and may develop permanent scarring if the infection penetrates deeply enough. Early intervention makes the difference between a quick recovery measured in weeks and a chronic problem that plagues you for months.

The condition is more common in certain horses than others. Horses with heavy feathering around their pasterns—like draft horses or those with genetic predisposition to feathering—tend to struggle more because the hair traps moisture against the skin. Horses with thin skin on the pasterns or those recovering from other injuries are also vulnerable. Understanding your individual horse's risk factors helps you implement preventive strategies before scratches has a chance to establish itself.

This guide will walk you through what scratches looks like in its earliest stages, the environmental and management factors that contribute to it, how vets diagnose and treat the condition, and most importantly, the practical daily management steps that keep your horse's pasterns healthy and infection-free.

Scratches develops when moisture, bacteria, and skin irritation combine in the pastern region, and moisture is the primary driver of this equation. The skin in the pastern is naturally more sensitive and prone to irritation than elsewhere on the horse's body, and when it stays wet for hours on end, the outer protective layer breaks down. This breakdown allows bacteria—particularly secondary bacterial infections—to colonize the area and trigger inflammation. The condition is fundamentally a failure of the skin's protective barrier, which is why moisture management is so critical to both treatment and prevention.

Environmental conditions play the biggest role in scratches development. Wet paddocks where horses stand in mud and moisture for extended periods create ideal conditions for the infection to establish. Morning dew on pasture grass, particularly in spring when horses first move to grass after months of dry hay, can trigger scratches in susceptible animals. Poor stall drainage where urine and moisture collect is another common culprit. Horses bathed frequently without proper drying, or those repeatedly exposed to hosing without follow-up drying, can develop scratches from the repeated moisture exposure. Even well-intentioned owners who hose legs regularly without fully drying them afterward are inadvertently creating conditions for scratches to develop.

Genetic and conformational factors make some horses more susceptible than others. Heavy feathering around the pasterns—that long hair covering the lower leg and hoof area—traps moisture against the skin and prevents air circulation. Horses with dense hair coats or those genetically predisposed to feathering are at higher risk. Horses with naturally thin or sensitive skin struggle more than those with thicker, more resilient skin. Pink-skinned horses, particularly those with white markings or minimal pigmentation, seem more susceptible than dark-skinned horses, possibly because their skin is more sensitive to sun and environmental irritation. Age also matters; young horses establishing their first healthy skin barriers and older horses with naturally thinner skin are both at risk.

Nutritional deficiencies can compromise the skin's ability to defend itself against scratches development. Poor zinc, copper, and protein intake weakens skin integrity and makes the barrier more vulnerable to breakdown. Horses on suboptimal diets with inadequate minerals are more likely to develop scratches when exposed to the same environmental conditions as well-nourished horses. Similarly, horses in poor overall condition or those recovering from illness have compromised skin health and are more susceptible.

Previous leg injuries or other conditions affecting the pastern region increase scratches risk significantly. Horses recovering from interference injuries, wire cuts, or other trauma in the pastern area are vulnerable to secondary scratches infection. Any break in the skin barrier—even minor abrasions—provides an entry point for bacteria. Horses with a history of scratches are prone to recurrence if environmental conditions aren't controlled, as their skin may never fully return to pre-infection resilience.

Seasonal factors influence scratches occurrence, with wet seasons presenting the highest risk. Spring is traditionally a high-risk time when horses transition to wet pasture conditions after dry winter months. Fall rains also trigger scratches in many parts of the country. Some horses struggle with scratches year-round in regions with persistent wet conditions, while others experience seasonal bouts corresponding to rainy periods. Understanding your local climate and your individual horse's seasonal patterns helps you implement prevention before scratches appears.

The earliest signs of scratches are easy to miss if you're not looking carefully, which is why regular pastern inspection during grooming is so important. Initial irritation appears as redness in the skin of the pastern, sometimes with slight swelling. The skin may look inflamed but without obvious lesions or scabbing yet. You might notice your horse is slightly more sensitive when you pick out or touch the affected area. If the pastern is heavily feathered, you won't see the redness at first—you'll notice your horse flinching when you groom the area or slight swelling between the fetlock and hoof.

As the condition progresses, small scabs begin to form in the creases and folds of the pastern skin. These scabs may have a crusty appearance and can look similar to dried mud at first glance, which is why casual observation misses early scratches. When you clean away the scabs gently, you'll see raw, irritated skin underneath. A foul odor often accompanies developing scratches, especially as secondary bacterial infection takes hold. That distinctive smell—sometimes described as musty or rotten—is your signal that bacteria are actively colonizing the affected area.

Swelling becomes more pronounced as the infection establishes itself. The pastern region visibly puffs up, the fetlock may appear enlarged, and in severe cases, the swelling extends up the back of the cannon bone. This swelling is often accompanied by heat in the affected area. When you run your hand over the pastern, it feels warm compared to the unaffected leg, and the horse may show pain or sensitivity when the area is touched. Some horses develop a noticeable limp or reluctance to bear weight on the affected leg, particularly if swelling is severe.

Discharge is a hallmark of moderate to severe scratches. A purulent, sometimes bloody discharge oozes from the lesions, particularly when you first clean the area. This discharge can range from mild seeping to copious drainage, and the color can be clear, yellow, or contain blood. The discharge may soak into the feathering if heavily feathered areas are affected, creating a matted, crusted appearance. When the affected area dries after exposure to moisture, the discharge forms thick, dark scabs that can look alarming.

Behavioral changes often accompany scratches, particularly if the condition is painful or advanced. Horses may walk stiffly on the affected leg, hesitate to move freely, or show obvious pain when the pastern flexes. Some horses react strongly to grooming or cleaning of the affected area, indicating the underlying skin is quite painful. You might notice your horse shifting weight off the leg, resting it, or moving with an obviously altered gait.

In severe cases that have been left untreated, the infection can penetrate more deeply, affecting not just the surface skin but underlying tissue. The lesions become larger, deeper, and more resistant to treatment. Some horses develop permanent scarring or thickened skin in the affected area. Secondary infections can develop, and in the worst cases, systemic infection or cellulitis can occur, causing fever and systemic illness. Horses with scratches that extends to the heel bulbs or becomes generalized across both hind legs are dealing with a more serious situation requiring aggressive veterinary management.

Diagnosis of scratches is typically straightforward—your veterinarian will examine the affected pastern, assess the extent of the lesions, and confirm the presence of the characteristic scabbing, swelling, and discharge. In some cases, they may take a sample or culture to identify the specific bacteria involved, though scratches is often a clinical diagnosis without requiring laboratory confirmation. The vet will also assess whether the infection has spread or whether secondary infections have developed. They'll examine both back legs since horses sometimes develop scratches on multiple legs simultaneously.

Your veterinarian will evaluate your horse's overall health and any systemic signs. If your horse is running a fever, acting lethargic, or showing signs of cellulitis—that spreading redness and heat extending beyond the pastern—more aggressive treatment becomes necessary. They'll also assess your horse's mobility and pain level to determine how much the scratches is affecting comfort and movement.

Treatment of scratches involves several simultaneous approaches: controlling the infection, removing debris and damaged tissue, creating an environment where healthy skin can regrow, and addressing the underlying moisture problem. Topical treatment is the cornerstone of scratches management. Your vet will likely recommend aggressive cleaning of the affected area, removing scabs and exudate to expose the underlying tissue. This sounds uncomfortable, and it can be, but removing the infected material is essential for the healing process. Many vets recommend daily or twice-daily cleaning, which you'll do at home after the initial professional assessment.

Antibacterial ointments or solutions form the second layer of treatment. Your vet may recommend products containing copper, iodine, or other antibacterial agents specifically designed for scratches treatment. Some vets use dilute bleach solutions or other disinfectants, while others prefer commercial products formulated for equine use. The specific product matters less than consistent application and proper cleanliness. You'll typically apply these treatments after cleaning and drying the area, often followed by a protective bandage or wrap to keep the area clean.

Systemic antibiotics are used in cases where secondary bacterial infection is present or the infection has spread beyond the localized pastern area. Not all cases of scratches require oral or injectable antibiotics—mild scratches caught early may respond to topical treatment alone. However, if your horse is running a fever, showing signs of cellulitis, or the condition is not improving with topical therapy, your vet will recommend systemic treatment. The specific antibiotic will depend on the bacteria involved, which is why some vets culture the discharge before prescribing.

Pain management is an often-overlooked aspect of scratches treatment. If your horse is lame or showing obvious pain, your vet may recommend anti-inflammatory medications like phenylbutazone or other NSAIDs to reduce swelling and improve comfort. Pain relief allows your horse to move more normally, which actually improves healing since movement promotes circulation. A horse that's severely painful and reluctant to move may develop secondary issues from immobility.

The most critical aspect of scratches treatment is eliminating moisture from the environment. All the topical ointments in the world won't resolve scratches if your horse keeps getting the pastern wet. This means moving your horse to a dry environment—a well-bedded dry stall, a dry paddock with good footing, or at minimum, keeping your horse out of wet grass and mud. If your horse must be turned out, keep grazing time in wet areas to a minimum. For horses kept outside, consider shelter that protects from rain and keeps muddy areas at a distance. This environmental management is often the difference between scratches that resolves in weeks versus scratches that lingers for months.

Treatment timelines vary dramatically depending on how early scratches was caught and how strictly moisture is controlled. Mild scratches caught in early stages might resolve in two to three weeks with good topical management and dry conditions. More established scratches can take six to eight weeks or longer. Severe, deep scratches or those that have become chronic may require months of treatment. The key factor in all cases is consistency—you must treat daily, keep the area clean and dry, and maintain those dry conditions throughout the entire healing period.

During active scratches treatment, your primary focus is creating and maintaining the dryest environment possible while keeping the affected area clean and medicated. If your horse has been living outside or in a wet area, moving to a dry stall becomes the first priority. Use dry shavings or other absorbent bedding, change bedding frequently to maintain dryness, and ensure excellent stall ventilation. Wet conditions in the stall will perpetually reinfect the scratches, so stall cleanliness and dryness are non-negotiable during treatment.

Daily cleaning is essential regardless of your stall situation. Most treatment protocols involve cleaning the affected pastern area daily or twice daily. Use lukewarm water and a soft brush to gently remove any scabs, discharge, or debris. Some protocols recommend gentle soaking in an Epsom salt solution before cleaning, which softens scabs and promotes drainage. After cleaning, thoroughly dry the area—this drying step is as important as the cleaning itself. Many owners use towels, while others use hair dryers on a cool setting to ensure complete dryness before applying treatment.

After drying, apply whatever topical treatment your vet recommended. Follow their specific instructions regarding product choice and application frequency. Some products go directly on the skin, while others should be applied to bandages or wraps. Some require daily application, others twice daily. Consistency matters more than any specific product—what matters is that you're applying the treatment as directed without skipping days.

Bandaging and wrapping play an important role in scratches management. A clean, dry bandage protects the treated area from environmental contamination, helps maintain dryness, and keeps topical treatments in place. However, bandages must be changed frequently—often daily—to prevent moisture accumulation under the wrap. A wet, dirty bandage creates worse conditions than no bandage. If your horse is very active or tends to get bandages dirty or wet, you may need to wrap multiple times daily. Some owners find that a light wrap over a medicated pad works better than heavier bandaging.

Nutrition and general health support accelerate healing. Ensure your horse is receiving adequate protein, zinc, copper, and other nutrients that support skin health. If your horse is in poor condition or recovering from other issues, good nutrition becomes even more critical. Some owners add targeted supplements supporting skin health during scratches treatment, though basic good nutrition is usually sufficient.

Once the acute scratches is resolved and lesions have healed, ongoing management focuses on preventing recurrence. For horses with recurring scratches, this means maintaining vigilance about moisture exposure. In wet seasons, these horses may need to spend more time in dry shelter or dry stalls rather than wet pasture. Some owners clip feathering short on horses prone to scratches since hair traps moisture. Regular pastern inspection during grooming catches any early signs of recurrence before scratches becomes established again.

Return to normal activity depends on how badly scratches affected your horse's movement and how severe the lesions are. Many horses remain sound for riding even with moderate scratches since the condition doesn't affect the structures involved in soundness. However, if your horse is lame from swelling or pain, continue to restrict activity until the condition improves. Once lesions are healing well and swelling is resolving, gradual return to normal activity is appropriate. Avoid prolonged soaking or intensive grooming in the healed area for several weeks after lesions close, as the new skin is fragile and vulnerable to re-injury.

Prevention of scratches is fundamentally about moisture management. Since moisture is the primary driver of scratches development, keeping the pastern region dry is your first line of defense. For horses with dry stall access, using this shelter during wet weather or high-risk seasons significantly reduces scratches incidence. Even horses that primarily live outside benefit from shelter access during heavy rain or when pastures are muddy. If your pastures have consistently wet areas, try to design grazing so horses spend minimal time in those zones during wet seasons.

For horses on pasture, monitor grass conditions carefully during spring and after rains when dew or moisture sits on the grass for extended periods. Horses can develop scratches within days of being turned out to wet spring pasture after months of dry hay. Consider bringing horses in during peak dew hours in early morning if scratches is a recurring problem. For horses at high risk—those with heavy feathering or genetic predisposition—limit grazing during wet seasons or bring them in more frequently than lower-risk horses.

Grooming practices impact scratches risk. Regular gentle grooming that keeps the feathering clean and dry is helpful, but avoid overly frequent bathing without careful drying. If you bathe your horse, thoroughly dry the pastern area and feathering with towels or a hair dryer. Don't leave a horse with damp legs standing in a stall or paddock where they'll re-wet their legs on wet grass or muddy ground. After exercise or bathing, create an opportunity for the legs to dry before your horse is exposed to wet conditions.

Management decisions can reduce scratches risk. Horses prone to scratches sometimes benefit from clipping or trimming feathering short since this reduces moisture retention. While this removes some of the aesthetic appeal of certain breeds, many owners find the health benefits worth the trade-off. Some consider this seasonal—clipping short during wet seasons and allowing feathering to grow back during dry seasons.

Prognosis for scratches that's caught early and managed properly is excellent. Early scratches typically resolves within weeks, leaving no lasting effects. Horses treated promptly usually make full recovery with no permanent scarring or ongoing issues. Even moderate scratches that requires several weeks of treatment generally resolves completely with proper management. The key factor determining prognosis is early recognition and strict moisture control throughout healing.

Horses with recurring scratches have the worst prognosis since once the skin in that area has been infected, it remains somewhat vulnerable to recurrence. These horses may require ongoing preventive management—spending more time in dry shelter during wet seasons, regular preventive drying after exposure to moisture, or even short-term topical prevention during high-risk periods. However, most recurring scratches is managed through prevention rather than repeated treatment cycles.

Severe, long-standing scratches that has gone untreated for months can lead to permanent scarring, thickened skin, or chronic issues that never fully resolve. These horses may always be slightly more susceptible to scratches and may require ongoing management. In the rare case where scratches becomes secondarily infected with more serious bacteria or develops into cellulitis or abscessation, the prognosis becomes more guarded and requires aggressive veterinary intervention. The bottom line is that scratches caught early and managed properly is a minor inconvenience; scratches ignored and allowed to progress becomes a chronic problem.