Lice and Mite Infestation
Learn what the condition is, how it may be detected early, how it is treated or managed, and which breeds or species are linked to it.
Condition snapshot
A concise guide to the condition’s pattern, detection, management and urgency.
Limit spread while seeking adviceSeparate affected animals when practical and obtain veterinary guidance on contacts, cleaning and normal mixing.
This snapshot is a general guide, not a diagnosis or treatment plan. New, severe or worsening signs require veterinary assessment.
About the condition
Lice and mites are external parasites that cause itching, scaling, hair damage and skin inflammation. Horses carry species-specific biting lice that feed on skin debris and sucking lice that take blood. Eggs, or nits, are glued to hairs. Chorioptic mites commonly affect feathered lower limbs, while rarer sarcoptic or psoroptic mites can cause severe generalised disease.
Lice are most evident in winter or early spring beneath long coats. Horses rub, bite and become restless; the coat looks moth-eaten or matted. Heavy sucking-louse burdens can contribute to anaemia and poor condition, especially in young, elderly or debilitated horses. Feather mites produce stamping, rubbing, crusting and thickened pastern skin and can worsen chronic progressive lymphoedema.
Transmission occurs mainly through close contact and shared rugs, brushes and housing. Equine lice do not usually establish on people. Mite host range and regulatory importance vary by species and country. Several horses may be affected while a well-groomed individual shows few signs, so treating only the visibly worst horse can fail.
Pruritus is not proof of parasites. Sweet itch, pinworms, dermatophytes, bacterial infection and allergy overlap. Conversely, negative skin scrapings do not completely exclude mites because sampling sensitivity is limited. Prognosis is favourable with correct species-directed treatment and repeat dosing, but long coats, untreated contacts and eggs surviving the first application commonly produce apparent recurrence.
Chewing lice feed on skin debris and create irritation, whereas sucking lice consume blood and can contribute to anaemia in a heavily infested, debilitated horse. Chorioptic mites favour feathered lower limbs and may persist in the environment or on mildly affected contacts. Winter coats often conceal burdens until rubbing, patchy hair loss and scaling become extensive.
Donkeys may carry heavy lice burdens with a different coat pattern from horses.
Screening & Early Detection
The coat is parted in multiple predilection sites under bright light. Adult lice move near the skin and pale nits remain firmly attached to hair shafts. Coat brushing onto dark paper or microscopic examination confirms species. Packed cell volume is checked in a debilitated horse with heavy sucking lice.
For mites, deep or superficial scrapings, tape preparations and plucked hairs are collected from active lesion edges and feathered pasterns. Several sites improve sensitivity; biopsy may be needed when severe compatible disease has repeatedly negative scrapings. Pinworm tape tests, fungal culture and skin cytology investigate common alternatives.
All in-contact equids are examined, including donkeys that may show different burdens. Rugs, grooming gear and recent movements are traced. Screening also looks for PPID, malnutrition or chronic illness when infestation is unexpectedly severe. Regulatory advice is sought for suspected notifiable mite species. Follow-up is timed after the parasite life cycle, not only when itching first subsides.
Sampling before parasite treatment improves the chance of identifying the species and its control requirements.
Treatment & Management
Treatment uses a product effective against the identified parasite and authorised for horses in the jurisdiction. Lice commonly respond to pyrethrin or pyrethroid sprays, wipes or powders applied all the way to skin as the label directs. Retreatment after roughly two to three weeks is usually necessary because eggs can survive the first application. Heavy coats may need clipping.
Mites require whole-horse or lower-limb acaricidal treatment repeated at the correct interval; lime sulfur, macrocyclic lactones or other products are chosen by the veterinarian because efficacy and licensing vary by mite. Thick feathers and crusts must not prevent skin contact. Secondary bacterial dermatitis and severe itch receive separate therapy.
All contact horses are treated together when transmission risk warrants it. Rugs, brushes, tack, trailers and stalls are cleaned and appropriately treated; items are not shared until control is achieved. Foals beside treated mares require special product-safety attention. Underlying PPID, poor nutrition and overcrowding are corrected. Success is confirmed by absence of live parasites on scheduled re-examination, since old nits can remain attached after cure and immediate visual improvement alone is misleading.
Breeds or species affected
Akhal-Teke
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Anglo-Arabian
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Arabian
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Barb
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Caspian
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Kathiawari
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Marwari
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Shagya Arabian
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Thoroughbred
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American Quarter Horse
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American Paint Horse
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Appaloosa
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Australian Stock Horse
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Brumby
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Waler
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Morgan
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Standardbred
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American Saddlebred
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Tennessee Walking Horse
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Missouri Fox Trotter
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Rocky Mountain Horse
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Peruvian Paso
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Criollo
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Mustang
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Canadian Horse
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Andalusian
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Lusitano
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Lipizzaner
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Friesian
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Dutch Warmblood
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Hanoverian
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Holsteiner
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Oldenburg
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Westphalian
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Trakehner
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Selle Français
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Belgian Warmblood
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Danish Warmblood
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Swedish Warmblood
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Swiss Warmblood
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Australian Warmblood
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Irish Sport Horse
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Cleveland Bay
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Württemberger
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Zangersheide
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Knabstrupper
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Orlov Trotter
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Camargue
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Icelandic Horse
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Pony of the Americas
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Quarter Pony
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Miniature Horse
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Clydesdale
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Shire
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Percheron
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Belgian Draft
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Suffolk Punch
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American Cream Draft
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Ardennes
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Breton
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Boulonnais
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Comtois
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Dutch Draft
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North Swedish Horse
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Norwegian Fjord
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Haflinger
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Gypsy Cob
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Irish Draught
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Welsh Pony and Cob
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Connemara Pony
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New Forest Pony
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Dartmoor Pony
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Exmoor Pony
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Shetland Pony
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Highland Pony
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Fell Pony
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Dales Pony
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Australian Pony
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Finnhorse
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Black Forest Horse
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