Ulcerative LymphangitisClinical signs, differential diagnosis, treatment and prevention in cattle and horses.

• Painful nodules and ulcers tracking distally along the lymphatic chains of the lower limb, most often the pectoral region in horses.
• Edematous swelling can extend up the entire limb; caused by Corynebacterium pseudotuberculosis.
• Chronic course; internal spread to organs carries 30–40% mortality.

• Peak incidence in summer and fall, when flying insects are present, though infection can occur at any time of year.
• Bacteria enter through skin wounds, carried by stable flies, horn flies or house flies; contaminated equipment or soil can also transmit them.
• Lesions spread distally along the lymphatic chains of the limb, and infection can spread internally to cause abscesses in organs such as the liver.

• Long-term (a month or more) systemic antimicrobial therapy directed at Corynebacterium pseudotuberculosis, combined with drainage of abscesses.
• Early external abscesses may respond to hot packing, poulticing, or hydrotherapy, with small abscesses lanced and flushed with iodine solution; internal infection carries a 30-40% mortality rate despite treatment.

MSD Veterinary Manual — Lymphangitis of Horses and Cattle (accessed 2026-08-11)

MSD Veterinary Manual — Lymphangitis of Horses and Cattle (accessed 2026-10-29)

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