My seven-year-old terrier cross is losing hair. She is well looked after and I can’t see any obvious problem. Can you tell me why this is happening?

James Farrell advises…

Hair loss can be a frustrating condition in dogs. Underlying causes can range from the benign and simple (always check for common parasites, such as fleas) to the more complex and potentially serious (liver disease).

Firstly, many breeds will lose their winter coat as the shorter secondary hairs come away. Some breeds need specific handstripping techniques to get rid of all the dead hair and prevent unwanted shedding later. If your dog is regularly groomed and still losing hair, then a trip to the vet is a good idea.

Your vet will probably start by ruling out external parasites. Sometimes people can feel offended by this, but please don’t, as it is such a common cause and sometimes not obvious. It is important to rule out benign, simple (and cheap) conditions first before starting more invasive and expensive investigations. Simply combing the coat will reveal fleas.

To look for mites, the vet might use the edge of a sharp blade to scrape the surface of the skin, which looks a bit uncomfortable, but this is to ensure that any mites living beneath the surface and in the hair follicles are revealed. The material is then scraped off and looked at under a microscope. Demodex is one such mite that causes hair loss by affecting the hair follicles. Treatment for demodectic mange usually involves a specific strong-smelling shampoo, so many owners leave the dog at the vet’s each week for a bath until the mites are all gone.

The wet weather last year made killing these parasites much harder, as the warm, wet conditions made for perfect breeding conditions and so many owners found that the regular treatments appeared not to work. New products are created by the manufacturers on a regular basis to combat this possible ‘resistance’ of parasites to older treatments. Your vet will be able to advise you of the most up-to-date and effective methods.

Other causes of hair loss include allergic conditions, for which blood tests may be done as a first step to examine your dog’s immune system and see what he is over-reacting to. With this information, you can try to avoid the trigger factors, or a novel and specific vaccine to your pet’s allergy can be made up to desensitise him to the allergic triggers (this is called immunotherapy).

Hormone conditions, such as an underactive thyroid or Cushing’s disease, will often cause loss of hair. Specific blood tests must be performed to diagnose these and most animals are managed quite effectively with medication. A poor diet and sometimes old age can cause hair loss. Occasionally, hair loss can be a result of more serious underlying disease, such as liver conditions or hidden cancers, but these are quite rare, and so owners shouldn’t worry about these, as a more common, treatable problem will probably be the reason.

Most dogs respond well to treatment, but do be patient, as the hair takes a good few weeks to grow back. Improvement is not always obvious at first.


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