Itching is an unpleasant sensation causing the desire
It is a defense mechanism but, if too intense or too long, ends up creating serious problems to the skin and to the animal quality of life.
In addition to scratching, dogs and cats may also manifest pruritus with exaggerated licking , chewing, rubbing against various surfaces and shaking the ears.
In cats owners sometimes find difficult distinguishing the normal grooming from itching.
Both dogs and cats tend to experience more itching when they are not distracted by other stimuli, typically when they are alone and at night.
The causes are several but the most common ones are external parasites, allergies and bacterial or fungal infections.
Regadless of the cause, in dogs skin, traumatized in aforementioned ways , reacts reddening in the acute phase and thickening and becoming pigmented in the chronic phase .
In cats the features are a little different (see factsheet "The cat is not a small dog").