To describe the natural history of a condition or disease. To describe the natural history of a condition or disease. To determine effectiveness or cost effectiveness of treatments/services and/or health care products. To measure or monitor safety and harm. To measure quality of care.
According to the NMSS, attacks or flare-ups of symptoms only qualify as exacerbations if: 1  they occur at least 30 days from an earlier flare-up. 2  symptoms last for 24 hours or longer.
The severity and duration of flare-ups varies from person to person and from time to time in the same person. 1  In mild cases, a flare-up may cause just one or two small, mild patches of inflammation. 2  In severe cases, the flare-ups can last several weeks or more and cover many areas of skin.