Itchy Skin

Scratching in Guinea Pigs

Scratching in guinea pigs can be caused by several common external parasites, including:

• Lice (Gliricola caviae and Gyropus caviae)

• Fur mites (Chirodiscoides caviae)
• Mange mites (Trixacarus caviae, also known as the “selnick mite”)

All three are usually spread by direct contact, although eggs may also be carried on hay, clothing, feeding utensils, and other shared items.

Lice

Lice rarely cause major discomfort for the guinea pig, although they are often more noticeable to the owner. These small grey or white lice, around 1.5 mm long, may sometimes be seen moving through the coat. More often, their eggs are seen attached to the hair, especially around the genital area and grease gland.

Treatment options include:

• Cat flea shampoo - 3 washes, one week apart
• Frontline spray
• Cat flea powder - 3 treatments, one week apart
• Fido’s Fre-Itch Rinse Concentrate, used strictly according to the product directions. The official directions state it should be diluted before use, applied to the animal, and not rinsed off afterwards.

If using Fido’s Fre-Itch Rinse Concentrate, bathe the cavy according to the label directions, avoid the eyes, and then dry the guinea pig thoroughly. Because guinea pigs can chill easily, many owners prefer to blow dry on a low, gentle setting until the coat is fully dry.

Fur Mites

Fur mite infestations rarely cause obvious symptoms. If scratching is present but there are no visible lice and no obvious skin irritation, treatment can usually be carried out in the same way as for lice.

Mange Mites

Mange mites live within the skin, where they tunnel through the surface layers. They can cause intense itching and, in some cases, especially in recently farrowed sows, may lead to raw sores. More commonly, they cause scaly or flaky skin and loss of the undercoat, giving the coat a moth-eaten appearance.

These mites may be present without causing symptoms. However, when a guinea pig is under stress - such as pregnancy, showing, weaning, fighting, or illness , the mites can take advantage of lowered resistance and begin to cause disease.

Washing hands thoroughly with soap and water after handling guinea pigs can help reduce transfer between groups. Infestations are often introduced when bringing in guinea pigs from another group. Mites may survive on clothing for a few hours, while eggs can remain viable in hay or bedding for several days. In most cases, direct contact between guinea pigs is needed for mange to spread, but mites may still be present even when no signs are visible.

Treatment

 Treatment should ideally be given to all guinea pigs in the group at the same time, whether they are showing symptoms or not, as parasites can be present even when signs are mild or not yet visible. 

Dose guinea pigs with sheep Ivomec at 0.25 ml per kg of body weight. Wash the guinea pig in cat flea shampoo, working it well into any scaly areas. Leave the shampoo on for 10 minutes, then rinse thoroughly twice. For the third and final rinse, use 2 teaspoons of sheep Ivomec in 2 litres of warm water. Dip the guinea pig in this solution, then dry thoroughly without rinsing again.

This treatment should be repeated weekly on affected guinea pigs until there are no remaining scabs or signs of itching. Most cases require 2 - 3 treatments, although severe infestations may need up to 6 treatments.

Ivomec is considered safe for heavily pregnant sows, but washing can be too stressful. In those cases, bathing should be delayed until several days after farrowing.

Common treatment options may include ivermectin or selamectin (sold under brand names such as Revolution), as these are widely used to treat external parasites such as mites and lice in guinea pigs. Because product strengths vary and these medicines are generally used off-label in guinea pigs, treatment should be given under veterinary guidance and according to the directions provided for that specific product or prescription.

If using a rinse product such as Fido’s Fre-Itch Rinse Concentrate, always follow the label directions carefully. Bathe the cavy as directed, do not rinse the product off unless the label says to do so, and dry the guinea pig thoroughly afterwards. Because guinea pigs can become chilled easily, many owners prefer to blow dry on a low, gentle setting until the coat is fully dry.

Dawn Mills
BVSc