What is Skin Disease?

Skin disease can usually be placed under 3 subheadings; infectious, allergic, toxic. Infectious and allergic dermatitis (literally inflamed skin) are the more common skin problems, but chemical exposure or contact can result in reaction.

Allergic Dermatitis

One of the most common problems seen with dogs is an allergy. Allergies occur when the immune system ‘over-reacts’ to foreign substances (allergens) the body is exposed to. The common reaction is itchiness, either localised to one area or generalised across the body. The reaction to this itchiness is to chew, lick or scratch. This can lead to hair loss, open sores and scabs and can lead to a secondary bacterial infection.

Treatment for allergic conditions involves removing the source of the allergy. Unfortunately, this is sometimes impossible, depending on what the allergic response is aimed at. Some dogs can be desensitised to allergens, where a tiny dose of the allergen is injected into the dog over a long period of time.

Symptomatic treatment is often the first line of treatment, where the over-active immune response is reduced to near normal levels. This provides relief from itchiness, but does not cure the allergy. Some allergies are seasonal, and need only to be controlled during the worst part of the year (usually summer).

There are several different ways to control the symptoms of allergy, these depend on the animal and the severity of the signs.

Bacterial Dermatitis

Dermatitis can often be as a result of bacterial infection, most commonly due to Staphylococcal bacteria. Staph bacteria are normally present on the skin of animals and humans, but they are considered opportunistic invaders. When the skin is healthy, there is often no problem, but when the surface of the skin is irritated or broken, they can invade and rapidly multiply until they cause disease. Problems that can cause itchiness often result in secondary infections, usually with Staph bacteria.

Staphylococcal infections usually appear as red areas of inflamed skin with either a pimple-like pustule in the middle or a larger, circular area or moist inflamed skin with a crusty edge and hair lost in the middle.

Skin biopsy and bacterial cultures can confirm a Staph dermatitis.

Staph infectious dermatitis is not infectious, as Staphylococci are normally found on living skin of all people, dogs and cats.

Treatment of Staph dermatitis revolves around reducing the number of bacteria present and eliminating any other problems that may have lead to scratching, such as allergies or fleas. Bacterial culture and sensitivity can determine a suitable antibiotic to use. Regular use of antibacterial shampoos can keep bacterial populations under control also removing loose hairs and dead skin flakes. Some infections require between 3 and 6 weeks of antibiotics therapy before coming under control.