Last Updated: October 30, 2026
Quick Summary
Proliferative pododermatitis, also called canker, is a serious foot infection that causes raised, granular tissue to grow on the frog, heel, or sole. Five key signs are lesions that will not heal, raised tissue that keeps growing, foul odor and moisture, lameness, and lesions that return despite routine care. If you see these, get a veterinary diagnosis.
- Lesions on the frog, heel, or sole that stay damp or oozing for weeks signal a problem.
- Raised, granular tissue that keeps growing is the hallmark sign that separates it from other hoof problems.
- A strong foul smell and a foot that stays wet even in dry weather are warning signs.
- Lameness on hard or uneven ground means the infection has likely been present for some time.
- If a lesion returns or fails to improve within three to four weeks, call your veterinarian.
Table of Contents
- What Proliferative Pododermatitis Is and Why It Matters
- Sign 1: Persistent Lesions on the Frog, Heel, and Sole
- Sign 2: Raised, Granular Tissue That Keeps Growing
- Sign 3: Odor, Discharge, and Moisture in the Lesion
- Sign 4: Lameness and Sensitivity When Walking
- Sign 5: Lesions That Return or Fail to Respond to Routine Care
- Canker vs Thrush in Horses: Telling the Look-Alikes Apart
- How a Veterinarian Diagnoses Horse Canker and Related Lesions
- Frequently Asked Questions
What Proliferative Pododermatitis Is and Why It Matters
Proliferative pododermatitis is a serious, slow-moving infection of the horse's foot, most often seen in the frog, heel, and sole. Unlike a simple case of thrush, the tissue does not just break down. It grows outward, forming raised, granular masses that keep spreading if nothing stops them.
Many horse owners first notice a problem that looks minor. A small patch near the heel or along the frog seems like a bit of irritation. Left alone, it can turn into a lesion that resists routine care and makes the horse sore on hard ground.
This guide walks through five signs that point to proliferative pododermatitis. It also explains how this condition differs from the look-alikes and what a veterinarian does to confirm it. Outlaw Horse Products was developed by a Journeyman Farrier with over 40 years of hands-on experience with horse hooves.
Sign 1: Persistent Lesions on the Frog, Heel, and Sole
The first sign is a lesion that does not heal. A normal hoof bounces back from small cuts and scrapes. A lesion tied to proliferative pododermatitis stays put, even after regular cleaning and trimming. For a dedicated canker treatment to act on it right away, see Outlaw Hoof Canker Care for equine canker.
Look for these details:
- The lesion sits on the frog, heel, or sole.
- It stays damp or oozing for weeks.
- Cleaning it brings a fresh bit of tissue or fluid back.
A common mistake is assuming the problem is just dirt or thrush and simply scrubbing harder. Scrubbing damages the tissue further and can make the lesion worse.
Sign 2: Raised, Granular Tissue That Keeps Growing
This is the sign that separates proliferative pododermatitis from almost every other hoof problem. The tissue does not just erode or soften the way thrush does, it rises above the normal surface of the frog, heel, or sole and keeps expanding. In horses, this is the hallmark of canker.
A useful way to recognize it is by stage, not by a single snapshot:
- Early stage: A small, slightly raised area near the frog or heel that looks grainy or wart-like. It may be mistaken for a minor abrasion or a bit of proud flesh.
- Established stage: The mass is clearly above the surrounding tissue, feels firm and rough rather than soft, and may bleed when touched or picked. It often spreads along the frog and into the heel bulbs.
- Severe stage: The growth covers a large portion of the sole or frog, produces a cauliflower-like texture, and may extend into the hoof wall. At this point the horse is usually lame and the tissue is difficult to manage without professional debridement.
Watch how the tissue changes between farrier visits:
- It grows larger rather than shrinking after cleaning.
- It feels firm and rough, not soft and mushy like thrush debris.
- It may spread to nearby areas of the hoof, including the heel bulbs and sole.
A farrier examining the frog can often spot this raised tissue early. Early detection makes a real difference, so do not wait for the horse to go lame before checking. A common mistake is to assume the tissue is just proud flesh from an old injury and to keep trimming it back without a diagnosis, proliferative tissue regrows quickly and needs a veterinary plan, not just repeated trimming.
The table below summarises how the raised tissue changes across the three stages described in this section.
| Stage | What it looks like | Key check |
|---|---|---|
| Early | Small raised area, grainy or wart-like | May be mistaken for a minor abrasion |
| Established | Clearly above surrounding tissue, firm and rough | May bleed when touched or picked |
| Severe | Covers large part of sole or frog, cauliflower-like | Usually lame; needs professional debridement |
Sign 3: Odor, Discharge, and Moisture in the Lesion
Many affected hooves give off a strong, foul smell. Some also produce a thin discharge that keeps the area wet. Moisture is a key factor because it lets the infection spread and makes it harder to heal.
Signs to note:
- A sweet or rotten smell from the foot, even after cleaning.
- Dark or yellowish fluid on the hoof wall or bedding.
- A hoof that stays wet even in dry weather.
Dry, clean stalls and regular hoof checks help control moisture. Keeping the hoof dry is part of managing the condition, not an optional extra.
Sign 4: Lameness and Sensitivity When Walking
Pain is a late but important sign. A horse with proliferative pododermatitis may step carefully, shift weight off one foot, or resist turning on hard ground. The lameness often worsens on gravel, rocks, or uneven footing.
Look for:
Outlaw Hoof Canker Care for Horses Canker Treatment →
- Short, careful steps on hard surfaces.
- Reluctance to pick up or hold the affected foot.
- Flinching when the frog or heel is touched.
If you see any of these signs, call your veterinarian. Lameness means the infection has likely been present for some time.
Sign 5: Lesions That Return or Fail to Respond to Routine Care
The last sign is persistence, and it is the one that most often gets ignored. Routine hoof care works for most minor issues. When a lesion keeps coming back after cleaning, trimming, and topical treatment, or when it fails to improve after several weeks of consistent care, the cause is likely deeper than thrush or a simple abrasion.
Watch for these patterns:
- Improvement for a few days, then a return of the same lesion in the same spot.
- No meaningful change after three to four weeks of consistent cleaning and treatment.
- A lesion that spreads even while other care continues.
- New lesions appearing on other feet.
This is also where practical triage matters. Most practitioners find that the following warrant a call to the veterinarian rather than another round of home care:
- Pain that is worsening or lameness that appears suddenly.
- Bleeding from the lesion that does not stop with light pressure.
- Rapidly enlarging tissue over days rather than weeks.
- Impaired walking or a horse that refuses to bear weight on the affected foot.
- Fever, swelling up the leg, or a foul discharge that suggests deeper infection.
At this stage, a clear plan from a veterinarian and farrier is essential. Canker treatment that removes diseased tissue and controls moisture is one part of that plan. Outlaw Hoof Canker Care is a topical treatment designed for use after the veterinarian or farrier has cleaned and debrided the affected tissue, and it should be used as directed by them. Our products are farrier developed and field tested for years, backed by forty years of hands-on hoof experience.
American Association of Equine Practitioners, finding your veterinarian
Canker vs Thrush in Horses: Telling the Look-Alikes Apart
Canker and thrush are often confused, and the difference matters for treatment. Thrush is a bacterial breakdown of the frog that usually smells strongly and affects the grooves of the frog. Canker, or proliferative pododermatitis, involves raised, growing tissue and tends to be slower and more stubborn. This explainer on equine canker signs, causes, and hoof care covers how the two conditions differ and how each is treated.
Key differences to check:
- Thrush: softer tissue, dark grooves, foul odor, typically responds to regular cleaning. For a side-by-side look at which treatment suits which condition, see canker care compared with thrush treatment.
- Canker: raised, granular growth, persistent lesions, often needs debridement and professional care.
Many horses have both conditions at once, so an accurate check is important. If you are unsure which one you are seeing, have a farrier or veterinarian look at the foot.
How a Veterinarian Diagnoses Horse Canker and Related Lesions
A veterinarian diagnoses canker by examining the foot, reviewing the history of the lesion, and ruling out other causes. They look at the size, texture, and location of the tissue and check how the horse moves. In some cases, they may take a sample to confirm the diagnosis.
Ask your vet about:
- What the lesion looks like and how fast it has changed.
- Whether the horse is in pain or has changed how it moves.
- A treatment plan that combines professional debridement with daily topical care.
Early veterinary care gives the best outcome. Do not rely only on home treatment if a lesion keeps growing or the horse is lame. This canker hoof care guide explains early action and when to bring in your farrier and vet.
Frequently Asked Questions
What are the signs of proliferative pododermatitis in horses?
The most noticeable signs are persistent lesions on the frog, heel, or sole, raised granular tissue that keeps growing, foul odor or moist discharge, lameness or reluctance to walk on the affected foot, and lesions that return after routine care. Because these signs overlap with thrush and other hoof problems, a farrier or veterinarian should examine the hoof to confirm the diagnosis before treatment begins.
How is proliferative pododermatitis different from thrush?
Thrush usually stays in the central and collateral grooves of the frog and responds to routine cleaning and drying. Proliferative lesions tend to be deeper, persist despite standard care, and form raised tissue that spreads. Canker is the term most often used for the proliferative form, which is why a veterinarian's diagnosis matters when routine thrush treatment is not working.
Can proliferative pododermatitis cause lameness?
Yes. Deep or spreading lesions can cause pain when the horse puts weight on the foot, which shows up as shortened stride, reluctance to turn, or a head bob at the trot. Lameness that worsens or does not improve within a short period is a reason to contact a veterinarian promptly rather than waiting out the problem.
When should I call a veterinarian about a horse's hoof lesion?
Call a veterinarian if a lesion is deep, bleeding, spreading, foul-smelling, or accompanied by lameness, or if it has not improved with routine hoof care. Your farrier can often identify a problem early, but a veterinary exam is needed to rule out infection extending deeper into the hoof and to plan treatment.
Outlaw Horse Products was developed by Robert Osborne, a Master Farrier with 40+ years of hands-on experience. Our formulas are built for hoof care professionals and horse owners who need dependable results. Outlaw Hoof Canker Care (8 oz, $42.99) is a maximum-strength topical for canker, severe thrush, and abscesses, designed to be used after debridement under a farrier's or veterinarian's direction. Visit our site to see the full line of hoof care products.
