What causes skin problems in dogs?
One of the first things you will notice when you meet with Koh Phangan's stray dogs is that so many of them have hair loss and very bad skin. They are often suffering with severe itching and can even be at risk of infection because of all that scratching. With the help of the community, we are often able to diagnose the problem here at the clinic and then treat the animal as an outpatient. In the more chronic cases, we may decide to admit the animal until the condition is brought under control. We get asked lots of questions about these conditions, here we will run through a few of the most common causes, methods of diagnosis and treatments.
There are a lot of factors that can cause skin problems. One of the factors can be that the dog has an allergy. This can be an allergic reaction to food or environmental factors such as pollen, cleaning products (including shampoo or parasitical treatments) or even the dog’s bedding fabric - if he is lucky enough to have such a thing on this island!
The development of a skin issue can also be caused by ringworm (Microsporum canis) infection. In contradiction to its name, ringworm is not a parasite, but a fungus. This type of infection occurs more often in young dogs than in old dogs. Since Thailand has a large population of stray dogs and the street dogs suffer from poor nutrition ringworm occurs more frequently here than in some parts of the world.
Probably the most well-known and common skin disease is mange, which we divide in Sarcoptic mange (also known as canine scabies) and Demodectic mange. Sarcoptic mange is caused by tiny oval-sized mites and is transmittable to both dogs and humans. Demodectic mange is caused by demodectic mange mites and is not contagious if the other dogs are in a healthy condition. These parasites reside in the skin and hair follicles and usually cause no harm. However, if the mites proliferate they can cause skin infections. This is what we see in many of our patients and also in the pet dogs on the island. Some breeds of dog find it harder to fight off the mites with their immune system and we think that some of those breeds have been busy breeding in the stray population here.
There are three types of Demodectic mange:
- Pododermatitis; affected area is confined to the paws.
- Localized; a few isolated spots on the body are affected.
- General; most of the body or the entire body is affected.
Symptoms and diagnosis of skin problems
Dogs with skin problems are prone to have an itchy skin. This causes the well-known scratching, rubbing and chewing of the itchy area which leads to loss of hair and bald patches. Other symptoms linked to skin issues are dandruff and reddened or darkened skin.
Most skin problems have very similar symptoms. Therefore, it is important that the veterinarian thoroughly analyses the skin and has insight on the dog’s history. Of course, in the case of a stray dog, this is almost impossible.
To find out whether the dog has a food allergy, the dog should be fed based on an allergy elimination diet (ask your veterinarian for advice). This basically requires you to eliminate specific food ingredients that are known to cause an allergic reaction, such as animal-derived proteins and starches. If the skin seems to get better, then you can add the eliminated ingredients back one at a time. If you notice the skin getting worse, you should eliminate that specific ingredient from your dog’s diet.
NOTE: Consult a veterinarian when switching to an allergy elimination diet. The veterinarian can advise you to ensure that the diet complies with your dog’s nutritional needs.
For the diagnosis of ringworm, the vet will probably scrape off a few skin cells. This skin sample will then be examined under a microscope. Another option is a microscopic analysis of a hair sample. Mange is also diagnosed through a skin biopsy, but since mange mites are often founder deeper into the skin a deeper skin biopsy is needed.
Leaving skin problems untreated can lead to other health complications. So it is important that treatment is started immediately after the diagnosis to eliminate the underlying cause. Besides the treatments for the cause of the skin problems, the dog is often treated with another medication to ease the itchiness.
Food allergy don’t usually require any medical treatment. With the allergy elimination diet, you can find out which ingredient you need to remove from your dog’s diet. Environmental allergens should be removed or replaced. For the airborne allergens such as pollen, the vet might prescribe antihistamine or cortisone.
If the vet has diagnosed a ringworm infection, the dog should ideally be isolated so that it cannot contaminate other dogs or humans. Ringworm is a fungus, not a worm as the name suggests. Therefore, a ringworm infection is treated with an antifungal medication on the skin. The dog may need to wear a collar with a cone to prevent ingestion of the medication depending on the specific treatment prescribed.
Mange is treated with anti-parasitic medication. There are several ways to apply this medication, e.g. topical, dip, injection, oral or with a shampoo. In the case of Sarcoptic mange, the dog should be isolated from other dogs.
Besides the medication, skin scrapes should be performed every 14 days. The medication can be cancelled after two negative skin scrapes. A final skin scrape after one month ensures that the dog is free of mange.
Once the dog has been treated it will take a while to get the skin back in a healthy condition. Skin cells take four weeks to mature, so after one month you should be able to see the first results.
If you have any concerns about the condition of your own dog's skin, please contact your vet immediately. Some conditions can take a long time to fully clear up so please also be patient and continue with the treatment prescribed. If you are not seeing results go back to your vet, they may need further medication or to try something new as not all dogs respond well to all treatments.
If you see a stray dog with the symptoms described above, please contact PACS with a full description, exact location details and, if possible, a photograph.