Like all subjects of study and practice, medicine has its own vocabulary. Attaching the suffix "-itis" to the end of a word, often a Latin word, can make many common illnesses seem more severe and more frightening than they often are. "-itis" means "inflammation" or "inflamed," which in turn means that the body's inflammatory process has occurred in certain body tissues. In practical terms, inflamed means red, swollen, painful, or tender.

Source: Contra Costa Health Services