eczema

Inflammation of the skin with reddening, formation of vesicles, and/or scabs. The cat aggravates the condition by scratching. The various types of eczeme can be caused by food poisoning, bad skin care, abnormal liver function, vitamin deficiency or allergy. The complaint may be acute or chronic, and may attack various parts of the body, especially the back and tail, the neck and the head.

SOURCE: cats.consultinghealth.com