🐴 Vet Guide to Horse Warts by a Vet in 2025

By Dr Duncan Houston BVSc

1. Introduction & Why Warts Matter

Equine warts—also known as papillomas—are a common skin growth in horses, particularly young ones under three. Although generally benign, these lesions can cause discomfort, spread easily among groups, and occasionally interfere with feeding or tack use. As a vet, I often reassure owners that most warts resolve naturally, but awareness and smart management are key. In this comprehensive 2025 guide, we’ll unpack everything from causes and diagnosis to treatment options and prevention, all designed to support a healthy, wart-free herd. 🛡️

2. What Are Equine Warts?

Equine warts are benign papillomas caused by equine papillomavirus (EPV), typically presenting as raised, verrucous bumps on the skin or mucocutaneous junctions. Common phrases like "grass warts" or "milk warts" stem from their prevalence in foals and yearlings when pastured. They're usually pink, grey, or white and measure around 0.2–2 cm in diameter and 0.5 cm in height :contentReference[oaicite:3]{index=3}.

3. Who Gets Them & Why?

• Age: Mostly seen in horses under three—especially foals and yearlings during their first grazing season :contentReference[oaicite:4]{index=4}.
• Immune status: Young or immunocompromised horses lack robust immunity.
• Skin injury: Papillovirus enters via microabrasions, insect bites, or sunburn :contentReference[oaicite:5]{index=5}.
• Environmental exposure: Shared gear, stalls, fences, even tack can spread virus between horses :contentReference[oaicite:6]{index=6}.

4. Recognizing Warts

Typically small (<2 cm), firm, cauliflower-like papules, often on:

• Muzzle & lips
• Eyelids & face
• Genital areas (penis or vulva)
• Ears, lower legs, mammary glands :contentReference[oaicite:7]{index=7}

They may crust, bleed, or become inflamed if rubbed or injured.

5. How Vets Diagnose

Diagnosis is typically clinical—based on appearance, distribution, age, and herd history. When lesions are atypical or solitary, we may opt for biopsy and lab analysis to rule out other conditions such as sarcoids :contentReference[oaicite:8]{index=8}.

6. Understanding the Virus

EPV includes multiple strains—nine known in horses—infecting epithelial cells and triggering abnormal cell growth :contentReference[oaicite:9]{index=9}. Most horses develop immunity post-infection; reoccurrence in adults is rare :contentReference[oaicite:10]{index=10}.

7. Natural Course & Prognosis

Most warts resolve on their own within 1–9 months :contentReference[oaicite:11]{index=11}. However, adult-onset EPV or aural lesions (“pinnal acanthosis”) may persist and require different approaches :contentReference[oaicite:12]{index=12}.

8. Treatment Options

8.1 Conservative Monitoring

“Watchful waiting” is effective in most cases—non-invasive, stress-free, and low-cost :contentReference[oaicite:13]{index=13}.

8.2 Surgical Removal

Recommended when warts cause pain, interfere with tack, or to confirm diagnosis. Surgical excision is curative, but scarring and recurrence—especially in adults—are possible :contentReference[oaicite:14]{index=14}.

8.3 Cryotherapy

Liquid nitrogen freezing is another option—effective but requires experience and care to avoid damage to surrounding tissue :contentReference[oaicite:15]{index=15}.

8.4 Topical & Immunomodulatory Therapies

Although treatments like imiquimod (stimulates immune response) or cantharidin (blister agent) are used in humans and dogs, their use in horses remains limited and off-label :contentReference[oaicite:16]{index=16}. Use only under veterinary guidance.

8.5 Duct Tape Occlusion (Home Remedy)

While duct tape therapy has anecdotal success in humans, equine-specific evidence is lacking. Risks include irritation or residue; not a veterinary recommendation :contentReference[oaicite:17]{index=17}.

8.6 Autogenous Vaccination (Experimental)

Horses may receive vaccines made from their own wart material—some success in young horses, but minimal impact in adults. Still mostly experimental :contentReference[oaicite:18]{index=18}.

9. Management & Aftercare

• Isolate infected horses and use dedicated equipment to prevent spread :contentReference[oaicite:19]{index=19}.
• Clean lesions with mild antiseptics; treat any bleeding to avoid fly strike :contentReference[oaicite:20]{index=20}.
• Insect control during warmer months reduces trauma and virus transfer :contentReference[oaicite:21]{index=21}.
• Monitor immune health: Good nutrition, deworming, low stress, and Ask A Vet support can expedite wart resolution.

10. Prevention Strategies

• Hygiene: Regularly disinfect shared gear, stalls, and water buckets :contentReference[oaicite:22]{index=22}.
• Quarantine new or infected animals until lesions resolve.
• Pasture rest: Allow older, immune horses to graze first, reducing viral load for young stock.
• Maintain skin integrity: Use fly repellents, clean tack areas, and avoid trauma.

11. Differentials: When It’s Not a Wart

Warts may mimic other skin issues:

• Sarcoids: Caused by bovine papillomavirus, often do not resolve, may re-grow after removal :contentReference[oaicite:23]{index=23}.
• Aural plaques: Coalescing lesions on ears tied to different papilloviruses; often persistent :contentReference[oaicite:24]{index=24}.
• Squamous cell carcinoma: Persistent, invasive, located near mucous junctions—must rule out early :contentReference[oaicite:25]{index=25}.

Biopsy is essential when lesions are atypical, solitary, ulcerated, or in adult horses.

12. Case Scenarios

Jessica, 8‑Month‑Old Foal

Multiple warts around muzzle appeared after pasture turnout—left untreated, they resolved in 5 months with quarantine and lesion cleaning.

Molly, 4‑Year‑Old Mare

Single wart on eyelid—surgically removed, healed well, with histopathology confirming benign papilloma. No recurrence at 1 year.

Toby, Adult Gelding with Aural Plaques

Persistent ear lesions diagnosed as pinnal acanthosis—comfortable and stable; monitored without intervention.

13. Role of Ask A Vet 🩺

At Ask A Vet, we're here for assistance with wart issues—veterinary assessment, teleconsultations, guidance on isolation, aftercare, and follow‑up. Download the Ask A Vet app for instant expert support and ongoing herd health checks.

14. Wrap‑Up & Key Takeaways

• Equine warts are common, benign, and usually self-limiting within 9 months.
• Observation and supportive care manage most cases effectively.
• Surgical or cryotherapy treatments are reserved for complications or interference.
• Isolation, hygiene, and fly control prevent spread within your herd.
• Always rule out sarcoids or carcinoma in adult or atypical lesions.

With informed management and veterinary support, most horses remain comfortable and wart-free. Let us partner with you—download Ask A Vet and get personalized care and peace of mind today! ❤️