Ringworm in cats is a fungus infection which is particularly common in young kittens. It does not cause the animal much discomfort, but it is highly infectious to man.
Kittens become infected early in life either from their mother or other infected individuals. Often the initial lesions are not very obvious and infected kittens are bought from fetes or pet shops or are given away without breeders realizing that they are distributing the disease.
The fungus invades the hair shafts and the outer layers of the skin. The first signs are usually around the face, ears and forelegs.
The skin becomes raised and crusty and the hair covering is thinner and some of the shafts of hair break. There is usually little irritation, and the extent of the infection is difficult to determine with the naked eye.
The great majority of ringworms are caused by the fungus Microsporum canis. One of its properties is that it emits a green fluorescence when exposed to an ultra-violet light. This enables vets to detect very early infections involving only a few hairs, and is invaluable in determining effectiveness of treatment.
Ringworm spores shed by infected animals are particularly long living. They are remarkably resistant to normal disinfectants and drying, and can remain capable of transmitting the disease for months. It is important to remove hairs from cushions, carpets and bedding by vacuuming.
Treatment is usually successful if the owner is patient. It involves giving the animal an antibiotic Griseofulvin and treating the skin with effective non-toxic preparations.
A dermatitis affecting older cats is commonly seen in autumn. The disease is not infectious to humans or to other cats and the precise cause is not known.
The acute form causes intense irritation. The cat starts to rub its back vigorously or scratch its face behind its ears or shoulders. It may spend much time licking around its tail or behind the back legs making the skin quite raw.
Commonly fleas are present and it is tempting to blame a hypersensitivity to flea bites. Fleas do aggravate the condition and a cure is not possible without first eliminating them. However, the problem does occur in cats free of fleas.
Some cats develop the condition every spring and autumn when it seems the skin is particularly sensitive to irritations, whether from flea bites, grass pollen, or certain dyes or fabrics.
A less acute form is seen in which small scabs develop around the head and neck, sometimes extending along the whole back. The scabs fall off with a small tuft of hair leaving the remaining coat mottled. Treatment usually consists of an anti-inflammatory injection.
Thorough grooming to help the cat remove shed hair is helpful. Remember to give cats a dose of paraffin once a week while they are molting to help them pass any hair they have ingested while grooming.