Alopecia in the Ferret
John R. Dinsdale, BVMS MRCVS
It is common for ferrets to be presented by owners worried by their ferret losing hair. A large percentage of the ferrets have no history of itching or signs of external parasites. In general practice the two most common causes in ferrets that have disease, and are not in fact simply going through the normal shedding either seasonal or breeding season related will be suffering from flea bite hypersensitivity or adrenocortical neoplasia. In order to reach an accurate diagnosis the following list of possible causes should be excluded. This is not exhaustive but provides a good basis on which to start. You have to remember that new diseases will be recognised as further interest is taken in the ferret and they get reported accurately.
Adrenocortical neoplasia (adrenal gland tumour)
Flea bite hypersensitivity
Hyperoestrogenism
Telogen defluxion
Breeding season alopecia
Shedding
Injection site reaction
Testicular neoplasia
Other causes
Probably the most common in our practice would be seasonal alopecia but a brief description of each will help to understand the dilemma of reaching a diagnosis in every case. A good history is essential in every case and this relies on the owner. More time will be spent below on important or life threatening causes than the more normal patterns of hair loss seen.
Adrenocortical neoplasia.
This is a very common cause of alopecia in the ferret, it is most common in the jill and usually occurs between two and five years of age. It generally starts in the spring on the tail or tail base and in some animals appears to come and go in some cases for several seasons, this may be because the ferret is also shedding at different times of the year. It becomes bilaterally symmetrical involving the tail base and flanks. The skin appears thin and shiny in a lot of cases and in the female you almost always see an enlarged vulva. Large numbers of black heads are sometimes seen on the tail and in some cases the enlarged adrenal gland can be felt in the abdomen, it is most commonly the left adrenal gland that is affected. If poldipsia and polyuria are detected you have to consider a concurrent stump pyometra infection in the neutered jill. Diagnosis is confirmed by exploratory laparotomy or ultrasound examination. It is wise to rule out as many of the other possibilities as possible before surgery.
Treatment involves removing the affected adrenal gland, often easier said than done as in the ferret the left adrenal gland is tightly adherent to the vena cava. There is a drug for medical management of the disease should the surgery not be possible or should the disease recur in the other adrenal in the future. Most ferret keepers will know this as an adrenal gland tumour, please note this has a very different presentation in the dog and cat and cannot be diagnosed by blood tests that would confirm it in the dog and cat.
Flea bite hypersensitivity.
This is certainly a common problem in ferrets presented to our practice. The disease is often associated with itching and scatching and generally adult fleas are not seen on affected ferrets but flea dirt's may be seen. Other in contact ferrets should be examined for fleas and thorough flea treatment instigated for all the ferrets kept and their environment. Previous articles have been published about flea treatment so this will not be dealt with here. I have no experience or knowledge of intradermal skin testing for flea allergen in the ferret. If in doubt it is wise to treat for fleas as it is a sensible precaution for the health and well being of your pet anyway.
Hyperoestrogenism.
This is far less common than ever it used to be as so many pet jills are neutered at a young age. However, in an entire jill it has to be possible cause of alopecia, the presenting signs are generally of a jill losing weight, pale mucous membranes, evidence of bleeding on mucous membranes and always a swollen vulva. The ferret will be generally very ill not eating and obviously systemically ill rather than just losing hair. The alopecia is due to oestrogen toxicity and is symmetrical involving the flanks, medial thighs and rump which progresses cranially. Treatment is generally very unrewarding, involving blood transfusions often repeated and surgery. The outcome is generally not favourable in any ones hands.
Telogen defluxion.
A non itchy symmetrical or patchy alopecia can occur many weeks after a period of severe illness or high body temperature, it can also occasionally follow surgery or anaesthesia and any such recent events should be taken into account. It generally affects the trunk more than anywhere else, and can present as alopecia or a reduction in the number of hairs present on the affected area.
Breeding season alopecia.
This is extremely common and is seen in the male and female although more common in the jill. It occurs typically from March to August with the coat growing back in the autumn. You must remember that some adrenal tumour cases do the same at first then fail to grow back so always consider adrenal tumour when looking at this condition. The hair loss is symmetrical affecting the tail, perineum, belly, rump and occasionally the feet and around the eyes. The ferrets are otherwise healthy.
Shedding.
Ferrets naturally shed hair in the early part of the year, spring early summer. The amount is variable and it grows back in within a couple of months, it is obviously not a disease process but the normal hair cycle in the animal.
Testicular neoplasia.
Very rare cases of alopecia associated with testicular tumours have been recorded in the ferret, they are even less likely to be seen in the future with so many ferrets becoming pets and being neutered.There are reports of an interstitial cell tumour and a sertoli cell tumour in the ferret.
Injection site reactions.
Some injectable products, for example vaccines and drugs used to suppress the breeding cycle of the jill have been seen to produce an area of alopecia at the injection site, this will be well circumscribed and the hair may or may not regrow.
Other causes.
You can see hair loss associated with poor diet including biotin deficiency. Biotin deficiency will occur in ferrets fed diets too rich in raw egg white. It is also worthy of note that as in all species a high burden of parasites internally will affect the health of the animal. It is good practice to routinely worm your ferrets and to report or note any periods of illness they may have.
I hope this has been useful and will provide a basis on which to work and give you some idea of the range of information you may be required to provide for your veterinary surgeon. This is not exhaustive and I am sure there is a wealth of information out there in practice above and beyond that which is detailed above.