Mud Fever: Treatment, Biosecurity & Prevention
- Horse Education Online
- 7 days ago
- 9 min read
Mud fever—also called pastern dermatitis or scratches—is a skin infection that targets the pasterns and fetlocks, often the hind limbs. Wet, muddy footing plus tiny skin nicks lets bacteria/yeast/mites take hold. Your first moves are simple and safe: bring the horse onto dry footing, part or lightly trim hair so you can see skin, do one gentle clean and full dry, then apply a thin, breathable barrier only when the skin is dry.
Avoid heavy pastes on damp skin and skip aggressive scrubbing—both trap moisture and prolong pain. Call your veterinarian if you see lameness, swelling, spreading lesions, or fever. For quick numbers and early-illness cues, use The Horse’s Vital Signs and How to Tell if Your Horse is Sick.
TL;DR (what to do first)
Dry footing now. Get out of the mud; towel legs completely dry.
See the skin. Part/trim feathers; don’t shave raw skin.
One gentle clean → full dry. No daily soaking or hard scrubbing.
Thin barrier only on dry skin. Reapply after each dry cycle—skip heavy pastes on damp skin.
Watch for red flags. Lameness, marked swelling/heat, foul odor, spreading lesions, or fever → vet same day (check ranges in Vital Signs).
Prevent repeats. Fix footing at gates/waterers, dry boots between uses, and keep feathers manageable; compare topline lesions in Rain Rot.
What mud fever looks like (vs. rain rot) — photos & quick ID
Mud fever (pastern dermatitis) starts low on the limb—at the pasterns and fetlocks, often the hind legs. You’ll feel firm, sticky crusts that pull hair when lifted. Underneath, the skin is pink, shiny, and tender, sometimes weeping a greasy exudate. Horses may snatch the leg or object to brushing because it hurts. In heavier breeds, feathers hide lesions—part hair to actually see skin.
As irritation continues, the area can swell and the horse may take shorter steps or resent flexing the fetlock. Lesions can ring the pastern like a “collar,” especially after days in mud or under rubby boots. Odor usually means prolonged moisture and secondary infection—tighten up drying and hygiene and call your vet if pain or swelling escalates.
How this differs from rain rot.
Rain rot prefers the topline (back, withers, croup). You’ll see the classic “paintbrush” tufts: small clumps of hair attached to a dry crust that lift off the coat. It’s rarely painful to flex a joint; the skin beneath is less raw than pastern dermatitis. If your lesions are under the fetlock and hurt to touch, think mud fever first. For a deeper comparison and management tips, see Understanding Rain Rot: Causes, Symptoms, Prevention, and Treatment.
💡Tip: Firm swellings on the pectoral chest or along the belly midline with fever point away from pastern dermatitis. Compare patterns in Pigeon Fever in Horses: Signs, Abscess Care & Isolation.
Quick ID table
💡Tip: If you can’t clearly see skin at the pasterns, part or carefully trim hair before judging severity.
At-home 2-minute pastern self-check (do this before treating)
1) Sight pass (30 s).
In good light, part hair at the pasterns and heel bulbs. Look for collars of crust, pink shiny skin, and areas that stay wet long after turnout.
2) Touch pass (30 s).
With clean hands, press lightly. Does the horse flinch? Is there heat or pitting edema above the pastern? Pain + heat suggests you should be gentler and call your vet sooner.
3) Environment pass (30 s).
Is the standing area dry? Do boots stay wet inside? Are feathers trapping grit? Fix footing and gear today.
4) Photo + note (30 s).
Snap a clear photo and jot one line: “Left hind, medial pastern ring; crust 2–3 mm; tender.” You’ll compare this nightly to confirm you’re improving.
If you see rapid swelling, a foul odor, or your horse won’t allow handling, skip home debridement and go straight to the vet plan.
Severity snapshot: stage your case in 60 seconds
Before you start treatments, stage what you’re dealing with. A quick, consistent scale helps you choose the right intensity of care and know when to escalate.
Stage 1 — Mild (home care likely)
Small patches of crust at the pasterns/fetlocks, pink but not angry skin, no lameness, minimal heat, horse tolerates gentle handling. Aim for dry footing + one gentle clean + thin barrier and monitor daily photos.
Stage 2 — Moderate (tighten hygiene, vet advice if not improving)
Crusts ring part of the pastern, tender to touch, mild swelling/heat, short steps when turning. Keep gear separate, improve footing, begin daily logs, and call your vet if no improvement within 48 hours.
Stage 3 — Severe (same-day vet call)
Marked swelling up the limb, obvious lameness, foul odor or copious exudate, or fever/dullness. Do not debride at home; keep the area dry and follow a veterinary plan.
One-glance staging table
💡Tip: Log temperature/heart/respirations once or twice daily so changes are objective. Normal ranges: The Horse’s Vital Signs.
First 48 hours: owner-safe treatment (don’t trap moisture)
Bring the horse onto dry footing immediately. Moisture drives the problem, so every choice in the first two days should reduce wet time and friction.
Step 1 — Hair management
Part or carefully trim long hair to expose skin and improve airflow. Don’t shave raw skin; tiny nicks worsen irritation. Aim for visibility and drying, not a show clip.
Step 2 — One gentle clean
Use tepid water with a dilute antiseptic once, then rinse well. Pat—don’t rub—until the skin is fully dry. Avoid vigorous scrubbing; it tears fragile skin and slows healing.
Step 3 — Thin, breathable barrier
When skin is dry, apply a light barrier (think “sheen,” not paste). Heavy occlusive layers trap moisture and macerate skin. Reapply only after each dry cycle.
Step 4 — Swelling, heat, or pain?
Cold-hose above the area if there’s pitting edema. If you note lameness, spreading lesions, or fever, call your veterinarian to guide analgesia and antimicrobials. Use these to track numbers and trends: The Horse’s Vital Signs and Average Heart Rate for a Horse.
What to avoid
Aggressive debridement, cycling wet → ointment → wet, re-exposing to mud before the skin is dry, and wrapping damp skin “to sweat it out.”
Owner hand-off checklist
Dry footing (stall mats or dry lot)
Trim/part hair for airflow (no shaving raw skin)
One gentle clean → thorough dry
Thin, breathable barrier only on dry skin
Check for swelling/lameness/fever; log vitals q12–24 h
Call vet if worsening after 48 h or if fever/lameness appears
Biosecurity & barn hygiene (when to isolate)
Mud fever isn’t always barn-wide, but sloppy hygiene makes it one. Treat it like you would rain-rot hygiene: keep gear separate and hands clean until lesions settle.
Separate gear, separate workflow
Assign dedicated towels, brushes, boots/wraps, and buckets to the affected horse. Work healthy horses first, then the affected horse last. Wash hands or change gloves between horses.
Disinfect the right things
Focus on high-touch items: cross-ties, door latches, grooming handles, and boot interiors. Launder towels and wraps hot; dry on high heat. Let boots dry completely between uses.
When to isolate the horse
Isolate if you see rapid spread, multiple cases in the barn, foul-smelling exudate with fever, or the horse won’t tolerate handling without pain. Isolation reduces cross-contamination while you stabilize skin and footing. For daily illness checks, use How to Tell if Your Horse is Sick.
Turnout rules while healing
Short, supervised turnout on the driest footing you have is fine once skin is dry and protected. Skip muddy lanes, deep puddles, and ill-fitting boots that rub the pasterns.
Quick barn hygiene checklist
Dedicated towels/brushes/boots; label and bag between uses
Handle affected horses last; wash hands/gloves after
Disinfect cross-ties, door rails, bucket rims after each session
Hot-wash laundry; high-heat dry
Isolate the horse if fever, foul exudate, or multiple cases appear
Want a printable, aisle-side vitals and first-hour checklist to keep with your towels and gloves? Follow our Emergency Colic Kit: First-Hour Actions & Vitals Checklist
Red flags: call your vet
Mud fever should start looking calmer within 48 hours of dry footing + gentle care. Escalate if anything below appears.
What triggers a same-day call
Lameness or the horse won’t allow handling
Marked swelling/heat up the limb or pitting edema (cellulitis concern)
Fever or dull/off-feed behavior (Follow our Fever in Horses guide and track numbers with The Horse’s Vital Signs)
Lesions spreading despite correct care for 48 h
Foul odor or copious exudate
Quick triage table (copy/paste)
💡Tip: Log time + number (e.g., “7:30 p.m. Temp 102.7 °F; HR 56”). Trends help decisions. Quick HR refresher: Average Heart Rate for a Horse.
Prevention that actually works (seasonal plan)
Think “less mud, less rub, less wet time.” Small footing fixes and a light routine on high-risk days prevent most flare-ups.
Footing and turnout flow
Mud fever is a moisture + friction problem. Keep choke points firm—gates, waterers, barn doors—so hooves don’t stand in slurry. If a lane stays soggy after rain, add drainage or reroute for a week. Short, dry turnouts beat long, wet ones; bring the horse in to dry legs fully before the next session.
Feather and skin care
See the skin, don’t guess through hair. Before the wet season, part or lightly trim feathers so pasterns can dry quickly. After any wash or rainy ride, towel the pasterns and heel bulbs until they’re completely dry. If you routinely miss the heel bulbs, set a phone reminder for a quick check at evening feed.
Barrier routine on wet days
On forecasted wet/muddy days, apply a thin, breathable barrier to clean, fully dry skin before turnout. Re-clean and re-dry after turnout, then reapply only if the skin is dry again. Heavy pastes on damp skin keep moisture in—exactly what mud fever wants.
Boot fit and rub control
Poorly fitted or always-damp boots grind grit into the pasterns. Check fit weekly, turn linings inside-out to dry between uses, and rotate pairs so interiors don’t stay humid. If a boot leaves a rub ring, retire it until the skin is calm.
Nutrition that supports skin
Skin heals better on a balanced ration and steady body condition. If forage is your main variable, review pros/cons and balancing basics here: The Basics of Equine Nutrition and Orchard vs Timothy vs Alfalfa: NSC, Protein, Ca:P—When to Feed Which. Hydration matters too—drying cycles work faster when circulation and skin turgor are normal.
Quick seasonal reset
Walk the paddock after the first big rain, fix one footing problem, trim/part feathers for visibility, and rehearse your dry → barrier → dry routine. If you catch pink, tender skin starting up, switch to dry footing for 48 hours and follow the early-care plan before it snowballs.
Seasonal checklist (barn-ready)
Mats/gravel at gates & waterers in place
Feathers trimmed/parted before rainy months
Barrier routine set for “wet days” only on dry skin
Boot fit checked; pairs rotated to dry interiors
Towels/boots laundered hot; drying rack ready
Nutrition review completed; BCS and water intake logged
Conclusion
Mud fever (pastern dermatitis) turns the smallest bit of wet-and-grit into a painful skin problem if we let moisture win. Keep it simple and consistent: dry footing first, see the skin (trim/part hair), one gentle clean → full dry, then a thin, breathable barrier—never heavy pastes on damp skin. Separate gear, tidy high-touch surfaces, and log what you see.
If swelling climbs, pain limits handling, drainage smells foul, or a fever appears, shift from home care to a vet-directed plan the same day. Stay ahead of the next storm with footing fixes, feather care, and a light “wet-day” barrier routine. That’s how you treat fast and prevent the repeat.
FAQ: Mud fever
Is mud fever contagious to other horses?
It can spread within a barn via shared brushes, boots, towels, and hands, especially when multiple horses stand in wet, muddy areas. Use dedicated gear, disinfect high-touch points, and work the affected horse last. Daily illness checks: How to Tell if Your Horse is Sick.
Should I wrap the pasterns for mud fever?
Only on dry, clean skin and under veterinary guidance. Wrapping damp skin traps moisture and worsens maceration. If your vet prescribes bandaging, keep layers breathable, change as directed, and re-dry the area between changes.
What barrier products work best?
Choose light, breathable films that repel splash while letting skin breathe. Think “sheen, not paste.” Apply after full drying and re-clean/dry before reapplying. Heavy occlusives on damp skin prolong mud fever.
Can I bathe the legs every day?
No—daily soaking keeps skin wet. Do one gentle clean, rinse well, and pat completely dry. On following days, spot-clean only if needed and prioritize dryness and barrier on dry skin.
Can my horse go out if it’s muddy?
Short, supervised turnout on the driest footing you have is fine once lesions are dry and protected. Avoid puddles, churned gates, and wet boots that rub the pasterns. Re-dry and reassess after turnout.
When do I call the vet for mud fever?
Same day for lameness, marked swelling/heat, foul odor, spreading lesions despite 48 hours of correct care, or fever/dullness. Track numbers with The Horse’s Vital Signs to guide triage.
Could mites, photosensitization, or EMS make mud fever worse?
Yes. Mites (especially under feathers), photosensitization (sun-reactive skin), and endocrine issues like EMS can complicate healing. Your vet may add skin scrapings, cultures, or diet/turnout changes. Nutrition basics: The Basics of Equine Nutrition.
How is mud fever different from rain rot?
Mud fever sits low—pasterns/fetlocks—with painful crusts and tender, pink skin. Rain rot lives on the topline (back/withers/croup) with “paintbrush” tufts and is less painful to flex. Compare patterns here: Understanding Rain Rot.
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