Ringworm – a fungal infection

Ringworm is a fungus that can cause superficial skin lesions and hair loss, but sometimes it may not show any clinical signs at all. While ringworm is usually quite easy to treat, it is highly contagious. Transmission to other animals and humans is possible so it is very important to confirm the diagnosis if ringworm is suspected, and to prevent environmental spreading as much as possible.

Ringworm is a superficial fungal infection that can affect the hair, skin or nails. It is usually characterized by hair loss, redness and flaky skin.

The name ‘ringworm’ is somewhat misleading as it is not caused by a worm; instead, it is caused by a fungi known as a dermatophyte. The typical dermatophyte species that infect rabbits are Trichophyton spp (especially in laboratory and outdoor rabbits) and Microsporum spp (especially in pet and house rabbits).

Ringworm is uncommon in rabbits. In most animals, ringworm is self-limiting; that is, it will resolve on its own over time, but treatments can be provided in severe cases or when multiple animals are affected.

Ringworm is a zoonotic disease, meaning that it can be transferred between animals and humans, so great care must be taken when handling animals with this condition to prevent humans from becoming infected.

Ringworm can affect rabbits at any age, but young, old, sick and immunocompromised animals are at higher risk. In addition, environmental stresses such as poor hygiene, overcrowding, malnutrition, fighting, and underlying diseases can be predisposing factors to increasing risk of illness from ringworm.

Ringworm may present as circular, raised, reddened skin lesions, scales, crusts and hair loss. The most frequently groomed areas are usually affected: the base of the ears and muzzle, but it can spread over the body and to the paws and nail beds. Infected rabbits can suffer from itching. It may also be symptomatic (no signs).

In group housed animals, multiple animals are usually affected, including other species such as dogs, cats and humans.

Your veterinarian will need to know the compete history of the problem and will carry out a physical examination of your rabbit.

Wood’s lamp examination can be helpful to detect some dermatophytes that fluoresce (glow) under a UV light. False-positives can occur due to a number of factors so this may not be the only test that is performed to determine the presence of ringworm.

Hair samples and skin scrapings will be taken from the periphery of the skin lesions to help determine if dermatophyte fungi are present. Hair follicles may be tested with potassium hydroxide or stained and microscopically examined to confirm the presence of a dermatophyte. A sample may be cultured in the laboratory to identify the specific fungal species involved.

Treatment for ringworm involves clipping the hair to reduce the amount of infectious hair shedding into the environment. The disease can be self-limiting in immunocompromised animals. In minor cases, topical creams can be used. In more serious cases, or in cases with multiple animals affected, oral tablets, shampoos, dips and sprays may also be used.

Isolation of infected animals is essential to reduce the risk of contagion. Environmental disinfection is very important as are barrier methods for preventing cross-contamination to humans.

Prevention begins with good hygiene, stress management, preventative health care, and prompt care of any presenting underlying diseases.