Skin diseases in both dogs and cats are one of the commonest and most difficult areas of companion animal veterinary practice. Indeed I understand that human dermatology is no less problematic. So where shall we begin..... There are a number of major groups:

Parasitic problems, bacterial disease, fungal disease, allergies, contact irritations, autoimmune disease and many others. Many textbooks have been written on this subject, and I am not about to write another. But I shall aim to cover the more important topics for dog and cat owners.........

PARASITIC PROBLEMS
1. And the commonest is....FLEAS!! Our old friend!! Fortunately for me, I've written a whole article on this subject already, and you may read it in our library of articles Enjoy!

2. Next we have the MANGES. These are caused by mites. And there are a number of them....
DEMODECTIC MANGE, or Demodex, is a condition of young puppies or occasionally of old dogs. It is generally thought to involve some kind of immune deficiency of the individual, which predisposes to the demodex infestation, as this mange does not seem to be infectious. It usually starts on the face, especially around the eyes, with simple baldness, which extends & worsens. It's not itchy at this stage. Some cases self limit, progress no further, and heal. But in others, pustules start to develop involving bacterial infection, and the problem escalates. Treatment of the infection with antibiotics is necessary, but eradication of the mites is essential and difficult. Many treatments have been tried, but Amitraz is the current favourite in our practice. Demodex does have a nasty habit of recurring however. Commonest in short haired breeds.

The next mange is SARCOPS or scabies. This is the VERY ITCHY one. There are 2 forms...doggy/foxy or human. And they're both infectious to dogs and humans. Often we see dogs with the human form, which they have caught whilst visiting a multi-person institution. And of course it can spread in the opposite direction. The skin becomes thickened and inflamed, especially behind the ears, in the armpits and groins of the dog. Treatment is a bit easier than with demodex. Amitraz can be used, as can organo-phosphate products. Or ivermectins, where they are licensed. In the UK a new product - Selamectin - has just been licensed for this and other uses.

And then we have CHEYLETTIELLA....or walking dandruff! This causes itchiness & much scurf, and is very common in Boxers. And Rabbits! Simple repeated insecticidal shampoos will usually resolve this, though it can also affect humans.

And in late summer we have HARVEST MITES which collect in small orange clumps between the toes, or on the belly of dogs and cats. They can be quite irritant. Again, bathing or spraying directly with an insecticidal treatment and repeating at weekly intervals will usually be effective.

And lastly we have EAR MITES (or "Canker) ....not so much a skin problem, but close. Ear mites cause loads of wax to form in the ears, and are very irritating. Also very infectious indeed. All dogs and cats in the house must be treated, cleaning out the ears, and then applying insecticidal ear drops repeatedly. I usually do this twice weekly for a month. But it's essential to treat ALL the pets. Otherwise, if just 1 or 2 mites survive in an untreated pet, then the whole problem will start over, a few weeks later!

Just one more.......TICKS!! In the UK, ticks are mainly an annoyance. But abroad, well there they may carry some very nasty diseases. If you are thinking of taking your dog to the continent on the Pet Travel Scheme, please read our library article on this subject first....it offers some very important advice.

In the UK, ticks (which always have a second species of animal in their life cycle) are usually sheep ticks or hedgehog ticks. They are small insects, which jump onto a passing dog or cat, and bury their legs into the skin of the pet. They feed off the pet, and then grow up to several milimetres in length. Then they usually fall off, if left to their own devices. However their removal is not quite so easy. Many things are suggested & none are perfect. The problem comes if most of the tick is removed, but tiny fragments of its legs remain embedded in the skin. This can turn into a nasty, septic, sore reaction lump. And will need veterinary attention. My personal favourite treatment is to spray the tick with an insecticidal spray and then to leave it to die and fall off. It works most of the time. But, prevention is better than cure. Frontline Spray or Frontline Spot On are reasonably effective preventions against ticks, though their period of action is shorter for this purpose than against fleas.

Occasionally, ticks can be responsible for spreading "Lyme Disease" in the UK - this causes a lameness and high temperature condition which can be quite difficult to both diagnose and to treat. But on the continent.....much nastier conditions can occur......

BACTERIAL DISEASES
There are a whole group of bacterial diseases affecting the skin. It will not help us to go into great detail here, but in simple terms, such diseases vary with the type of organism involved, and how deep the infection penetrates within the skin.

The commonest skin pathogen is Staph aureus, but there are many others including E.coli in various forms and Pseudomonas. If a bacterial skin problem becomes difficult, then it is very important to 1. Identify the organism and then 2.Carry out an antibiotic sensitivity test on the organism itself. This will detect the most useful antibiotics to use. It will also detect those to which the bug is resistant, and which would be useless. This can save a lot of money! Antibiotic treatment is very important. It also may well need a long course to deal with a skin problem, far longer than the 5 day course that we may be accustomed to. So do be patient. If your vet prescribes a one or two month course, it is likely to be for a very good reason.

WET ECZEMA is a particular form of bacterial skin disease. It looks the worst, but is usually easier to treat than a dry bacterial eczema! Wet eczema tends to occur in warm/hot weather, and it starts off with a minor scratching and in no time erupts into a wet, septic area of discharge. It's important to clip & clean the area with mild antiseptics. Stop the pet scratching the affected area, and use antibiotics, either topically, or by mouth, for several days, according to your vet's advice.

ANAL FURUNCULOSIS is an horrendous disease of GSDs. It involves the massive breakdown of tissue next to the anus, with secondary infection. But antibiotics alone will not sort this one out. It is now thought to be caused by an auto-immune condition, where antibodies attack normal tissue. Until recently, radical surgery was the usual treatment, but now, the anti-rejection drug cyclosporin is being used, with some success.

FUNGAL DISEASES
1. Ringworm is NOT caused by worms! But by one of a group of fungi. It is a highly infectious disease, not particularly itchy, and needs very specific treatment. Usually a dog or cat will catch ringworm from either another animal, or from an infected place - such as a kennel, cattery, calf shed, stable, fence post etc. Wooden buildings will carry ringworm spores indefinitely. Wooden buildings are not a good idea when ringworm gets into them! They CANNOT be properly disinfected.

Diagnosis of ringworm requires a plucking of the fur from the edge of the affected area to be cultured. The fungal culture can take 1-4 weeks to grow, so you have to be patient. If positive, then specific anti-fungal treatment is necessary. Either an antibiotic called griseofulvin can be used -but NOT in pregnancy - or various baths/washes can be administered regularly. It's a long job.

MALASSEZIA
This is a relative newcomer to the scene and has only been recognized in recent years. It is another fungal infection, involved in longstanding, greasy/seborrhoeic type skin conditions. Once diagnosed, it is best treated using a new anti-bacterial & anti-fungal shampoo called "Malaseb". Malassezia can be part of a long term problem.

ALLERGIES
Oh, where do we begin!! There are just so many, and varied allergies. So we'll need to keep it simple. Allergens (the things triggering allergies) can be inhaled, ingested, or touched by the skin. So that opens up vast numbers of possibilities.

The commonest allergens are flea saliva, and house dust mites. But then there are also pollens, certain dietary proteins ( eg dairy products & gluten), grass, household chemicals, and many, many others. Generally, allergies are suspected in itchy skin problems, where other, mainly infectious causes, have been ruled out. Tests can be done to attempt to identify the allergen involved. There are recently developed blood tests, of varying accuracy. And some dermatologists will carry out intra-dermal patch testing.

IF you identify the allergen, then treatment is SIMPLE!?!?! Avoid the allergen! That's not usually so simple at all!! But you have to TRY!

Sometimes, a dermatologist may suggest a desensitization programme.
But as FLEAS are the commonest allergen, thorough flea control is usually the most important basis for allergy management.....and again I draw your attention to the article on FLEAS in the Library at www.vetontheweb.com House dust mites......well the most recent vacuum cleaners with high suction and microfine filters would certainly help, if used often. Also the new household spray..."INDOREX" claims to have some efficacy against house dust mites.

And dietary proteins.......well there are now a number of diets to use on an exclusive basis e.g. Pedigree Selected Protein with Capelin; Hills d/d with Duck and Rice; and others. Take a look at the special diets in our Veterinary section at www.petz.co.uk

CONTACT IRRITATIONS
These are often considered to be allergies. But they aren't really. These problems are caused by the irritant effect of a substance which the dog is lying on, on the dog's skin. So the problem will usually be confined to the belly area & the underside of the paws. Substances involved include cement dust from building work, dry carpet shampoos, caustic type irritants, new carpets, and freshly cut grass. And there are doubtless many, many more! The simple proof of a direct contact irritant is to put the dog into a bland environment - such as a wooden based kennel - and see if the problem disappears.

AUTOIMMUNE DISEASES
These are diseases where the body reacts against itself - in this case against its own skin tissue. Conditions such as Anal furunculosis -mentioned above under Bacterial Diseases - would be included. But the biggest group of conditions here are the "Pemphigus" group, which have various manifestations. These are really specialist diseases, of complex basis. Steroids are often necessary to control them.

And so....
There we have a resume of skin diseases in dogs and cats. Out of all this, are there some simple lessons to learn.......

1. Never forget FLEAS! They're the commonest single cause of skin diseases, and so many times, owners have told me that the pet has no fleas.......but I've found them!! PREVENTION is better than cure!!

2. Pets lick themselves. To excess. And so often, 95% of skin damage is caused by this. If only they'd stopped licking, the problem may well have cured itself. Pets DO NOT lick themselves better, so stop them doing it.

3. When the going gets tough.....get an expert! Skin disease is frustrating. But you're not alone. Talk it through with your vet. Vets are getting much better at dealing with skin disease. BUT occasionally we all need the support of a specialist veterinary dermatologist. So, if things aren't going well, discuss a referral to one of the specialists with your vet - who will no doubt be happy to organize it for you.

4. Pet Insurance......skin disease can be particularly expensive. Prolonged & repeated treatment is often necessary. And Pet Health Insurance will take the financial sting out of this one.

Tim Mainland MA, VetMB, MRCVS
www.vetontheweb.com

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