Mange is a skin condition that is caused by several different species of parasitic mites that are invisible to the naked eye. These tiny mites embed themselves in either the skin or hair follicles. The two most common mange mites are the Demodectic mange mites and the Sarcoptic mange mites.
Demodectic Mange (Demodicosis)
Demodectic mange mites infect both cats and dogs of any age or breed, but is more common in dogs than cats.
It may surprise you to know that a very small population of demodectic mites of various species live on the bodies of virtually every mammal without causing any harm or irritation. Puppies and kittens pick up the mites from their mothers shortly after birth.
Transmission occurs through direct contact only. The various species of demodectic mange mites tend to infect only one species, e.g. Demodex cati infects cats, Demodex bovis infects cattle and Demodex follicilorum infects humans.
Life cycle of the demodectic mange mite
The demodectic mange mite spends its entire life on the hair follicles and sebaceous glands of the skin of its host.
Eggs are laid by a pregnant female from which six-legged larvae hatch. The larvae undergo several moults before becoming eight-legged nymphs. The nymphs ultimately mature into eight-legged adult mites. The whole cycle takes about 20 to 35 days and is completed entirely on the host. The mites cannot survive off the host.
Types of demodectic mange
There are two main varieties of demodectic mange, namely, localised and generalised.
Localised demodectic mange affects specific parts of the body, especially the face and limbs in dogs and the face and neck in cats.
Generalised demodectic mange affects the entire body.
Symptoms
Localised demodectic mange symptoms in dogs are characterised by a mild, itchy, patchy hair loss on the head and limbs. In cats it is characterised by hair loss and crusts as well as some itching, scaling and redness of the skin around the face, neck and eyelid.
Generalised demodectic mange symptoms will be seen all over the animal’s body.
Causes
Demodectic mange is not a disease of a poorly kept animal or dirty living conditions or environment. It is usually a result of an underdeveloped or suppressed immune system. Although mange in cats is rare, Siamese and Burmese breeds appear to be predisposed.
Diagnosis
Skin scrapings and hair samples are used to identify and diagnose demodectic mange in cats and dogs. In the case of generalised demodectic mange the possibility of an underlying disease must also be investigated.
Treatment
Localised demodectic mange can be treated with a topical treatment. Sometimes it resolves spontaneously without treatment.
Generalised demodectic mange may require extended, aggressive therapy to resolve.
The use of isoxazoline ectoparasite treatments, like Bravecto and Nexgard, has largely taken over as a treatment regime in pets.
Sarcoptic Mange (Scabies)
Sarcoptic mange is a highly contagious parasitic skin condition that is caused by the mite, Sarcoptes scabiei. It can infest dogs and cats of any age or breed, but is extremely rare in cats.
These mites burrow through the skin causing intense itching and irritation.
Transmission occurs through direct contact with an infected animal or from a contaminated environment, e.g. crate, kennel or dog bed. Transmission can occur to humans, but is generally self-limiting causing only temporary itching.
Life cycle of the sarcoptic mange mite
The female mite burrows into the skin and lays her eggs several times as she continues burrowing. After laying her eggs, the female dies. The eggs hatch into six-legged larvae. The larvae moult into eight-legged nymphs that them mature into eight-legged adults. The entire life cycle takes place on the host and takes about 2 to 3 weeks.
Although the mite prefers to live on the host, it can survive for several days in the environment.
Symptoms
Symptoms can vary from dog to dog, but the most common signs are intense itching and hair loss. Often there will be red pustules and some crusting of the skin. Because of the intense itching, the dog will scratch and may traumatise the skin, causing sores and secondary bacterial infection.
Causes
The most common cause of sarcoptic mange is exposure to another infected animal and/or infected environment. It takes about 2 to 6 weeks after exposure for symptoms to display.
Treatment
Treatment includes topical or systemic acaricidal products, anti-puritic therapy and antibiotics to treat any secondary bacterial infection.
There are also spot-on treatments, e.g. Revolution and Advocate, that can be used to help treat sarcoptic mange.
Ongoing treatment is necessary to kill all of the mites as the eggs will take time to hatch, and most treatments do not kill the eggs, only the living mites.
The use of isoxazoline ectoparasite treatments, like Bravecto and Nexgard, has largely taken over as a treatment regime in pets.
If you suspect that your pet may be suffering from mange please consult a veterinarian and follow the prescribed treatment rigorously.
