A dog's environment today, like ours, is radically different from what it evolved in. The majority of us spend 95 percent of our time indoors or in transport. So do our dogs and cats! Houses are relatively air tight with higher humidity and temperature than ever, conditions ideal, for example, for dust mite multiplication. For increasing numbers of dogs and cats exposure to dust mites triggers immune system cells in the skin to release their chemical contents, many of which are irritating and cause itchiness. In allergy, eosinophils are stimulated by a variety of environmental factors and subverted from natural parasite targets to attack your pet's own tissues. The resulting 'chemical spillage' causes increased scratching, licking and chewing. Itchy skin disease in pets has increased enormously in the last 40 years.
What sometimes makes the diagnosis of the cause of itchiness difficult is that there need not be any inflammation (or secondary infection) associated with itchiness. Responding to itchiness is the most common way pets tell you there is something wrong with their skin. They respond to itchy skin by:
- Nibbling or chewing
- Itchy skin may also lead to personality changes including:
- Loss of tolerance
Specific causes of itchy skin include
- Harvest mites
- Ear mites
Diagnosis and treatment of pruritus
Parasites are seen on the skin or found on skin scrapes or smears. Bacteria or fungi such as Malassezia are found on skin smears or cultures. Allergy is diagnosed by intradermal skin tests or ELISA tests, exclusion diets or environmental control. Treatment also aims at eliminating the cause and treating any secondary conditions. For allergy this is not always possible, simply because determining the exact causes of allergy is a frustratingly time-consuming affair. Antihistamines and corticosteroids are often used to prevent further skin damage from licking and scratching. Frequent shampoos remove allergens as well as scales and crusts that form an ideal environment for secondary skin infection.