There are four types of multiple sclerosis (MS). Each type may have a mild, moderate or severe course. MS can also change types over time.
- Description: This type of MS is marked by a series of relapses (periods when symptoms get worse) and remissions (or periods when symptoms are better). The course is a back-and-forth switch between a worsening and an improving of symptoms.
- Course: During the relapse phase (also called “flares,” “exacerbations” or “attacks”) a person will notice loss of function and often develop new symptoms. During the remission period, these symptoms fully or partially disappear. Corticosteroids are often used to shorten the duration of relapses.
- How Common?: This is the most common type of MS, representing 85% of new diagnoses.
- Description: In this type of MS, people experience a slow but steady worsening of symptoms.
- Course: Generally people gradually become worse over time, though the rate of worsening varies greatly among people.
- How Common?: About 10% of MS is primary-progressive.
- Description: People with secondary-progressive MS were originally diagnosed with relapsing-remitting MS. These people have stopped having periods of remission and experience a slow but steady worsening of symptoms.
- Course: Varies greatly for each individual, though symptoms usually steadily worsen over time.
- How Common?: About 50 percent of people with relapsing-remitting MS developed secondary-progressive MS within ten years. However, this was before the widespread use of disease-modifying medications. Researchers are still waiting to learn the effects of these medications on the progression of MS.
- Description: People with progressive-relapsing MS have a steady worsening of symptoms along with exacerbations.
- Course: A steady worsening of symptoms without the periods of remission found in relapsing-remitting MS.
- How Common?: About 5% of all people with MS have progressive-relapsing MS.