In this column veterinarian Dr Liesel van der Merwe provides practical assistance for common problems in companion animals. She is a specialist physician at the Onderstepoort animal teaching hospital and a senior lecturer in the section of small animal medicine. Send your questions to This e-mail address is being protected from spambots. You need JavaScript enabled to view it

Dr Liesel van der Merwe

Scratching dogs are one of the most common complaints a vet has to deal with. The reasons for itching include infection, parasitic skin infections and allergic disease.

The root cause is often an allergy to something in the environment, and little, apart from desensitisation injections, can be done to control this. Allergens, such as pollen and dust mite, are taken in through the dog’s skin.

What you can do to help your dog is to improve the skin’s resistance and increase the threshold at which itching will become evident.

Make sure that there are no skin and intestinal parasites. Effective control of ticks, fleas and worms is essential as these can induce an allergic reaction. Topical applications, “spot-on treatments”, should not be applied immediately after bathing the dogs. Allow a gap of four days before and four days after bathing. The active ingredient needs to spread along the natural oils on the skin and then builds up in the skin glands.

Make sure that there is no skin infection. Due to all the scratching, dogs can develop a mild skin infection, showing as small pimples. This is really itchy and will need to be controlled with antibiotics from a vet. A good antibacterial shampoo can also be used, but make sure it isn’t too harsh and drying on the skin.

A good diet will result in a healthy skin. Good quality proteins and the correct amount and ratio of omega three and omega six fatty acids are important. Omega three fatty acids are found in salmon oil.

They are of immense benefit in cases with skin problems as they are incorporated into the membranes on the skin cells and make them more resistant to inflammation and itching.

The turnover of the dog’s skin is 20 days and it takes about four to eight weeks to notice the effect of improved nutrition. Increased oils in the food makes more anti-oxidants in the food necessary to prevent it from becoming rancid.

Premium quality foods contain these ingredients, and some lines offer special care diets for dogs with sensitive skins. Adding sunflower oils to food will increase the coat’s shine but will not have an anti-inflammatory effect on the skin.

Excessive washing is a problem, especially in small breed dogs. Washing with shampoo should be kept to an absolute minimum as the detergent action strips off all your dog’s natural oils, drying out the skin. This will eventually predispose to bacterial infection, which causes a distinctive odour.

Rather brush out mud or wash with plain water if you can. A dog’s skin is more alkaline than that of humans (pH=7.5 versus 5.5). Using a “mild” baby shampoo is not advised. A good quality physiologically “normal” veterinary shampoo should be used on animals which are frequently bathed.

Attention should also be placed at not getting water in the ears: block with cotton wool, or place swimmer’s solution into the ears before bathing.

Cats also itch and will demonstrate this by over-grooming and licking bald patches. They also develop little scabs around their faces. Make sure no external parasites are present, and increase the plane of nutrition to a premium food which does not contain any protein of fish origin. Fish and milk proteins are a major cause of allergies in cats. Check the list of ingredients of the food you are buying and remember, just because it says chicken flavour does not mean that there is no fishmeal in the product.

If all these factors are being addressed and your pet is still itching, then visit a vet for diagnostic tests. It is likely that your pet has an allergic skin disease. You should expect the condition to be controlled by medication, not cured, unless you can identify and remove the source.