Despite also being commonly called a mange mite too, demodex mites are very different from the other mange mite which causes sarcoptic mange. Uncommon to rare in cats, the demodex mites live within the hair follicles, rather than burrowing, and can be difficult to diagnose.
In cats there are two species of demodex – the most common, Demodex cati, are normal residents of cat skin, and only ever cause problems if they overgrow – unusual in a healthy, adult cat. The second species, Demodex gatoi, are much rarer but can be transmitted between cats and can cause intense itching.
A demodex infestation can happen on any cat with an overgrowth of the parasites, but is much more common in young cats or those with a poor immune system, such as cats with FIV, diabetes or Feline Leukaemia Virus.