Guinea pigs can suffer from a number of skin parasites or infections. These can cause hair-loss and itchiness (pruritus) and require treatment. It is important to diagnose which parasite or infection is causing your guinea pig's skin lesions in order to treat them appropriately. In this blog I will run through the most common skin lesions in guinea pigs. Ringworm: Ringworm is not a worm but caused by a fungal infection, usually with a fungus called tricophyton mentagrophytes. Young animals are affected more often than older animals. Lesions are usually found around the head area and typical show hair loss, with crusting and scabbing. You will find that the hair falls out very easily at the edges of the lesions. If it is a mild case, it is usually not itchy. If the case is more severe, it can spread to other areas of the body and become itchy. This can result in the lesions becoming infected. The condition is zoonotic, meaning that lesions can spread to humans from the guinea pig. To prevent the transfer to owners, it is important to wash your hands after handling or treating you guinea pigs. If you notice similar lesions on your skin, please consult a pharmacist or doctor.
Ringworm in guinea pigs can be diagnosed by appropriate clinical signs and/or a fungal culture. All guinea pigs living together should be treated if one of their cage-mates has lesions. There are several different types of treatment available including washes, ointments and oral preparations. Treatment should continue for several days beyond the lesions resolving.
Lice: Lice are a type of insect living in the coat and skin surface of affected guinea pigs. The most common louse found on guinea pigs is called gliricola porcelli, another louse called gyropus ovalis can be found in some cases. Both of these lice are termed biting lice (which means they feed on surface skin cells), sucking lice are uncommon in guinea pigs (these feed by sucking blood).
Lice are very itchy, skin lesions occur as a result of this itching and include: hair loss, scabs and thickened skin. You will be able to see the lice in the coat of the guinea pig, usually around the rump or the back of the neck. They are about 1mm long and cream coloured. Diagnosis is by seeing the lice and/or performing a tape strip exam under a microscope. Lice pass from guinea pig to guinea pig easily, if they are in close contact; but do not pass to humans. Treatment is usually with topical insecticides and anti-inflammatories to control the itch and discomfort.
Mites: There are a number of mites affecting guinea pigs, the most common are trixacarus caviae (sarcoptic mange) and Chirodiscoides caviae. Trixacarus caviae is a mite that burrows into the skin, because of this they cause extreme itchiness and pain. The itch can be so severe that the guinea pig may start seizuring. Guinea pigs with this mite will commonly show hair loss n and the skin may become thick, yellow and crusty. Secondary bacterial infections often occur due to breaks in the skin from itching. The guinea pig may show generalised signs of illness due to the pain including lethargy, inappetance and weight loss. Treatment is usually with injectable antiparastic agents alongside pain relief. In addition, bedding will need to be thoroughly cleaned. Although not common, this mite can be transmitted to humans. Wear gloves when handling affected guinea pigs. If you notice lesions on your skin, please consult a pharmacist or doctor. Chirosdiscoides caviae are a non-burrowing mite and therefore produce very mild signs, and sometimes may not be associated with clinical signs at all. Unless they are causing clinical sign, these can remain untreated. If treatment is required, topical or injectable antiparastic agents can be used. Often, owners are concerned about white flecks in their guinea pig's coat. These flecks could be related to dry skin or they could be chirosdiscoides caviae. Neither are a significant cause for concern unless the guinea pig is itchy.