If dystonia develops in childhood, particularly if it starts in the legs, it may frequently spread to other parts of the body, and may become generalized. When dystonia develops in adulthood, it is usually confined to one body part (focal dystonia). If it spreads, which is very unlikely, it will usually affect only one other area, which is commonly the nearest muscle group.
The progress of dystonia is however unpredictable. The severity of symptoms may fluctuate, even from day to day. Typically, a focal dystonia will progress very gradually over a several year period, and then no longer progress. Rarely, dystonia may sometimes improve or disappear altogether for no apparent reason.