What is fever coat?

Loki a kitten with fever coat. Image (modified background): @badcatty, Twitter

Two useful tags. Click either to see the articles: Toxic to cats | Dangers to cats

Fever coat can affect cats, rabbits and dogs as I understand it. It is also called “stress coat”. It should not be confused with “powder coat” (possibly due to the caramel gene). It is an abnormality in the coat of a new-born kitten in which the tips of the hair strands lack pigmentation and are silver creating a sort of smoke coat appearance. This unusual appearance is temporary and lasts around four months, but it can take up to 12 months to resolve in some cases.

There are no known health consequences. The migration of pigment throughout the hair strands is clearly interrupted and affected by what is believed to be a high temperature in the womb caused by the mother having a fever because of illness or prolonged stress. In short, the development of the kittens in respect of their coat is affected by the mother’s health.

Verdell has a powder coat. Image: Social media. I have changed the background. — Verdell has a powder coat. Image: social media. I have changed the background.

However, a kitten’s coat pattern and colour are hardwired into them through their DNA and therefore this temporary anomaly is rectified. You can see that fever coat creates an interesting appearance. The picture of a kitten above, posted on social media, called Verdell went viral. I guess people wanted to adopt this particular kitten or kittens like him. It was explained to social media users that it was a temporary condition.

Subsequent posts on social media of this particular cat shows him to be black after a gradual transition.

Black and white kitten with fever coat. Image in the public domain.

As usual, the best explanation comes from Sarah Hartwell on her website messybeast.com. She goes into great detail. She adds that the mother might be on medication at the time of pregnancy. This also can create kittens with fever coat.

She confirms that the pigmentation, melanin, has not been properly distributed or deposited in the fur strands and can appear, as you see in the photograph, silvery-grey. The coat can also appear cream or reddish. And sometimes they can have a Siamese-like coloration.

Hartwell also mentions that rarely a kitten with a fever coat can have stripes of grey hair down their back on either side of their spine called dorsal stripes. Hartwell assessed this cat to be affected by fever coat although an alternative cause could have been leukotrichia. ‘Leukotrichia’ means white hair and is a condition which reduces or removes melanin in the hair follicle due to a loss of pigment producing cells in the skin called melanocytes.

Hartwell also mentions that kittens might have “fever coat” without a fever ?. The cause may be genetic. Hartwell refers to a breeder, Judy Miller, of Siberian cats who told her that she has seen fever coat in kittens whose mothers did not have a raised temperature during pregnancy.

Hartwell says that kittens carrying the colourpoint gene are more sensitive to womb temperature than others. Also, colourpoint gene carriers may be heat sensitive and this may be the cause of fever coat without a fever on occasions.