Does your pet scratch, lick, or chew themselves excessively? Itchy skin is a very common problem in dogs and cats, particularly at this time of year in Darwin with the onset of the wet season.
There are many different causes of itchy skin in pets, and it is important to try to work out what the cause is, so that we can determine how best to help them. It is no fun for them to be constantly irritated! A consultation with your vet is the best place to start, but these are the most common causes of itchy skin that we see:
Flea allergy is a very common cause, sometimes we will see fleas, or flea dirt (little black specks in the coat), but not seeing fleas on your pet does not rule out flea allergy! Animals with flea allergies are constantly licking and chewing and can quickly remove the evidence of fleas, and it only takes a small number of fleas to cause a significant problem in allergic pets. Whether fleas are seen or not, we recommend all itchy pets (and all cats and dogs in their household) maintain excellent flea control. Many flea products can take 24-48 hours to kill the fleas (eg. spot-on treatments), or only work for a short time (eg. flea shampoos). A product which kills fleas within hours and keeps working until the next dose is given is needed for pets with flea allergies – talk to us about the best option for your pet.
Atopic dermatitis (Atopy) is also a common cause of itchiness. It is a complex disease, involving an allergic reaction to commonplace and otherwise harmless substances, such as the pollens of weeds, grasses and trees, as well as house dust mites, mould spores, and even insect body parts. There is some genetic basis to atopy, and certain breeds are more likely to be affected. It is now known that skin barrier dysfunction also plays a significant role in atopic dermatitis, and repairing this skin barrier is an important part of treatment. Atopic dermatitis in dogs is diagnosed by history, physical examination, and ruling out other causes of itching. There are many treatment options for management of this condition, and allergy testing can be done to determine what your pet is allergic to. Your vet will work with you to determine the best options for you and your pet.
Food allergies can affect dogs of any age, and occur after months to years of eating a particular food, rather than in response to a new food. Food allergies are not seasonal and can cause severe itching in dogs. Up to 50% of dogs will also have gastrointestinal signs such as vomiting or diarrhoea. The most common food allergies are reported to be beef, dairy products and wheat, but reactions to most protein sources are possible. A strict food trial is needed to diagnose food allergie, simply switching to another brand of pet food is not likely to resolve the problem – talk to us about how to do a proper food trial.
Demodex mites are present in the hair follicles of most dogs, and in some dogs they can overgrow to cause a problem (demodecosis). Some pets with demodecosis are itchy, particularly if it is complicated by a secondary infection. Demodecosis is most common in puppies and young dogs, before their immune system matures, but it can occur at any age. It is usually diagnosed by taking some scrapings from the skin and seeing mites under the microscope.
Another type of mite, the sarcoptes mite is less common in the patients we see, but is highly contagious, and causes severe itching in dogs. It can also affect people. It can be more difficult to detect, and a treatment trial may be recommended if sarcoptes is suspected.
Skin infections with bacteria, yeasts, and occasionally fungi (ringworm) can cause significant pruritis (itchiness). Samples can be taken from the skin surface and examined under the microscope to help diagnose bacterial and yeast infections. Often infections occur secondary to allergies or ectoparasites (such as fleas or mites) and it is essential that these are identified and treated or the itching is likely to persist.
What can we do?
Unless the likely cause of itching is obvious on examination (eg. some cases of flea allergy) your vet will usually need to do some further testing. This is likely to include examining some samples under the microscope to look for mites and infection. A flea treatment trial and a food trial may be recommended. For animals with atopy, allergy testing can be done to determine what they are allergic to.
Once we have determined the likely cause of the itching, we can work with you to develop a treatment plan that is manageable for you and your pet. For dogs with atopy, lifelong management will be required for most pets.
Treatment may consist of a combination of oral medication, topical medications (cream or sprays) shampoos, bath oils, omega- fatty acids or special diets. Desensitisation injections are available for dogs with atopy.