Trixacarus caviae Mange in Guinea Pigs

TL;DR. Trixacarus caviae mange is a common, highly contagious skin disease in guinea pigs caused by a burrowing mite, resulting in extreme itching, hair loss, and crusty skin lesions.

Trixacarus caviae mange typically causes severe hair loss and crusty lesions starting around the neck and shoulders.

What is it?

Trixacarus caviae mange, often simply referred to as guinea pig mange, is a severe and highly uncomfortable skin disease caused by the microscopic mite Trixacarus caviae. This parasite belongs to the same family as the mites that cause sarcoptic mange in other animals. It is a burrowing mite, meaning it physically digs microscopic tunnels into the outer layers of your guinea pig's skin to feed, live, and lay its eggs.

This burrowing activity triggers an intense inflammatory response. For guinea pigs, this results in some of the most severe itching seen in veterinary medicine. Because guinea pigs are exotic pets, much of our clinical approach is guided by specialized exotic animal medicine and veterinary dermatology standards. Understanding how this parasite behaves is critical for pet owners, as the condition can quickly compromise a guinea pig's quality of life if left untreated.

When a guinea pig is infested, the constant irritation can lead to extreme stress. In severe cases, the physical toll of the constant scratching and subsequent skin damage can make the animal highly vulnerable to secondary bacterial infections, weight loss, and severe lethargy.

Causes & risk factors

The sole cause of this condition is the transmission of the Trixacarus caviae mite. This parasite is highly contagious and is primarily spread through direct, physical contact between guinea pigs. If an uninfected guinea pig shares a living space, plays with, or is housed near an infected individual, transmission is highly likely.

Additionally, the mites can occasionally be spread through indirect contact. This occurs via contaminated bedding, cages, grooming tools, or toys (fomites) where mites or their eggs may temporarily survive.

While any guinea pig can contract the mite, certain risk factors increase the likelihood of a subclinical infection (where the guinea pig carries the mite but shows no signs) turning into an active, severe disease outbreak. These risk factors include:

• Stress from overcrowding or sudden environmental changes
• Poor husbandry and inadequate cage hygiene
• Underlying nutritional deficiencies, particularly vitamin C deficiency (scurvy)
• Concurrent illnesses or a compromised immune system

There are currently no documented breed predispositions for Trixacarus caviae mange. All breeds of guinea pigs, from the smooth-coated English to the long-haired Peruvian and the hairless Baldwin, are equally susceptible to infestation if exposed to the mite.

Signs to watch for

The clinical signs of Trixacarus caviae mange are distinct, primarily characterized by extreme physical discomfort. As an owner, you should monitor your pet closely for the following signs:

• Intense pruritus (Cardinal): This is the hallmark sign of the disease. The itching is so severe that guinea pigs will scratch, bite, and rub their skin relentlessly. The scratching can be so violent that it may resemble a seizure or convulsion when the guinea pig is touched or stimulated.
• Neck, shoulder, and inguinal lesions (Common): Hair loss (alopecia), redness, and thick, gray-white crusts or scabs typically develop first in these specific regions. The skin in these areas often becomes thickened, dry, and highly sensitive.
• Self-inflicted trauma (Common): Due to the relentless scratching, guinea pigs will often scratch themselves until they bleed, creating open wounds and raw patches of skin.
• Secondary bacterial skin infections (Common): Open wounds caused by scratching are easily invaded by environmental bacteria, leading to localized pus, warmth, and increased pain.
• Lethargy and weight loss (Rare to Common): In chronic or severe cases, the constant pain and stress prevent the guinea pig from eating or resting normally, leading to systemic decline.

The intense itching associated with Trixacarus caviae often leads to self-trauma and raw, bleeding skin.

How vets diagnose it

Diagnosing Trixacarus caviae mange begins with a thorough physical examination and a review of your guinea pig's housing and medical history. Because other skin conditions can mimic mange, your vet will need to perform specific diagnostic tests to confirm the presence of the mite.

"Rabbits and guinea pigs with intense pruritus should be checked for their respective mites because this would be the most common differential."
— Small-Animal-Dermatology-A-Color-Atlas-and-Therapeutic-Guide, p. 500

The primary diagnostic methods include:

• Microscopy of skin scrapes: This is the gold standard for identifying burrowing mites. Because Trixacarus caviae lives beneath the surface of the skin, your vet will perform a deep skin scraping. This involves gently scraping the affected skin with a sterile scalpel blade until a tiny amount of capillary bleeding is observed. This ensures the sample contains material from the deeper layers where the mites reside. The collected material is then placed on a glass slide and examined under a microscope.
• Tape preparations: For surface debris or suspected surface-dwelling mites, your vet may press clear adhesive tape against the skin and hair coat to collect mites, eggs, or skin flakes for microscopic evaluation.

"Diagnosis: Microscopy of skin scrapes (deep if suspecting Sarcoptes scabiei ) or tape preparations for fur mites, demonstrating the parasite or ova."
— Small-Animal-Dermatology-A-Color-Atlas-and-Therapeutic-Guide, p. 500

It is important to note that a negative skin scrape does not entirely rule out a mite infestation. Because these mites can be elusive or present in low numbers, your vet may still recommend treating for mange if the clinical signs are highly suggestive and other causes, such as fungal infections (ringworm) or bacterial pyoderma, have been ruled out.

Treatment options

Treating Trixacarus caviae mange requires eliminating the parasite from both the animal and its environment. All guinea pigs in the household must be treated simultaneously, even if they are not currently showing clinical signs, to prevent reinfection.

First-Line Therapy: Ivermectin

Ivermectin is the primary and most effective treatment for Trixacarus caviae mange. It belongs to the macrocyclic lactone (avermectin) class of antiparasitic drugs. It works by disrupting the nervous system of the mites, leading to their paralysis and death.

Your vet may administer ivermectin orally, via subcutaneous injection, or topically (applied directly to the skin). Topical application is often preferred in exotic medicine due to its ease of administration and excellent absorption.

"In general, the treatment for mites in most species is ivermectin at 0. 2 mg/kg PO, SC, or preferably topically repeated in 10 to 14 days, with some important exceptions: never use ivermectin in turtles or tortoises—it can cause paralysis, coma, death as a result of their permeable blood-brain barrier; never inject ivermectin into birds, especially small b"
— Small-Animal-Dermatology-A-Color-Atlas-and-Therapeutic-Guide, p. 501

Because ivermectin only kills active mites and not their eggs, the treatment must be repeated at least once, typically 10 to 14 days later, to eliminate newly hatched mites before they can reproduce.

Second-Line Therapy: Amitraz

Amitraz is an antiparasitic agent belonging to the formamidine class. It may be considered as an alternative or second-line therapy if first-line treatments are ineffective or unavailable. However, amitraz must be used with extreme caution under strict veterinary supervision, as guinea pigs can be highly sensitive to its side effects.

While specific dilution and application protocols exist for other species, your vet will determine the safest concentration and application method if this therapy is required for your guinea pig.

Prognosis

Long-term prognosis data in this species is limited in structured veterinary literature. However, standard clinical experience indicates that the prognosis for guinea pigs with Trixacarus caviae mange is excellent if the condition is diagnosed early and treated appropriately.

Most guinea pigs show a rapid reduction in itching within a few days of starting first-line therapy. Hair regrowth and complete skin healing typically occur within a few weeks. If the infestation has progressed to severe self-trauma or secondary systemic illness, the recovery period may be longer, and supportive care (such as pain management, fluids, and antibiotics) may be necessary to ensure a positive outcome.

Prevention

Preventing Trixacarus caviae mange relies on strict biosecurity and hygiene practices:

• Quarantine: Always quarantine any new guinea pig for at least two to four weeks before introducing them to your existing pets. Monitor them closely for any signs of scratching or hair loss during this period.
• Sanitation: Regularly clean and disinfect your guinea pig's cage, toys, and food dishes. Wash all fabric bedding in hot water.
• Minimize Stress: Provide a quiet, low-stress environment with a balanced diet rich in Vitamin C to keep your guinea pig's immune system strong.
• Avoid Wild Contact: Ensure your guinea pigs do not come into contact with wild rodents or other pets that could carry external parasites.

When to call your vet

You should contact your veterinarian if you notice your guinea pig scratching more than usual, losing hair, or developing crusty skin patches.

You must seek immediate emergency veterinary care if your guinea pig is scratching so violently that it experiences seizure-like episodes, is bleeding from self-inflicted wounds, or has stopped eating and drinking entirely.

Sources

• Small-Animal-Dermatology-A-Color-Atlas-and-Therapeutic-Guide, pages 500, 501
• Plumb's Veterinary Drug Handbook, page 3879