Understanding Mud Fever (Pastern Dermatitis)

Mud fever is one of the most common skin conditions affecting horses during wet weather. Although often associated with winter, it can occur at any time of year when the skin becomes damaged and infection is able to develop.

What Is Mud Fever?

Mud fever, also known as pastern dermatitis, greasy heel or cracked heels, is an inflammatory skin condition affecting the lower limb. It usually begins around the heel bulbs and pastern before progressing further up the leg if left untreated.

The condition develops when the skin barrier becomes damaged, allowing bacteria, fungi, mites or other infectious agents to invade.

Causes

Mud fever is rarely caused by one factor alone. Common contributing causes include:

· Prolonged exposure to wet, muddy conditions.

· Skin irritation or abrasion.

· Mites.

· Bacterial or fungal infection.

· Trauma to the skin.

· Heavy feathering that traps moisture.

· Repeated leg washing.

· Irritating bedding or soils.

· Poorly fitted or dirty bandages and overreach boots.

· Photosensitisation.

· Allergic skin disease.

· Reduced immune function.

· Tumours affecting the skin.

Clinical Signs

Signs vary depending on the severity of the condition but commonly include:

· Hair loss.

· Scaly skin.

· Crusting or scab formation.

· Thickened skin folds.

· Serum discharge.

· Ulceration.

· Pain and swelling.

· Itching, stamping or biting at the legs.

· Lameness in more advanced cases.

Diagnosis

If you suspect mud fever, veterinary advice should always be sought.

A veterinary examination may include skin scrapings, hair samples, swabs or other tests to identify bacteria, fungi or mites. Information about your horse's management, turnout conditions and field companions can also help establish the underlying cause.

Treatment

Treatment depends on the underlying cause, but the overall aim is to eliminate infection, protect the skin and allow normal healing.

· Clip excessive hair where appropriate to improve access.

· Only remove loose scabs that are ready to detach naturally.

· Wash using products recommended by your veterinary surgeon, such as medicated, iodine or chlorhexidine shampoos where appropriate.

· Rinse thoroughly and dry the legs completely using a clean towel.

· Apply prescribed antibacterial or other topical medications as directed.

· Keep the horse in clean, dry conditions whenever possible.

· Use barrier creams if turnout in wet conditions cannot be avoided.

Additional treatments, including antibiotics, antiparasitic medication or anti-inflammatory drugs, may be prescribed depending on the individual case.

Prevention

Good stable management, avoiding prolonged exposure to deep mud where possible, regular inspection of the lower limbs and prompt treatment of small skin injuries all help reduce the risk of mud fever developing.

Summary

· Mud fever is a common inflammatory skin condition of the lower limb.

· It develops when damaged skin allows infection to establish.

· Early diagnosis and treatment improve the outcome.

· Keeping the legs clean and dry is an important part of management.

· Always seek veterinary advice if the condition is severe or persistent.

A Final Thought

Mud fever often begins as a small skin irritation but can rapidly become a painful and difficult condition if ignored. Early intervention almost always leads to a simpler and more successful recovery.

About the HØØF Knowledge Hub

The HØØF Knowledge Hub exists to provide horse owners with clear, practical and evidence-based information on hoof health, lower limb conditions and farriery.

Every horse is an individual, and no online article can replace professional assessment. If you have any concerns about your horse's health, always seek advice from your veterinary surgeon or registered farrier.

Article Information

Author: Paul Conroy BSc (Hons) AWCF
Organisation: HØØF Equine Hoof Care
Category: Lower Limb Conditions
Document Reference: HKH013
First Published: July 2026
Last Reviewed: July 2026