What types of MS are there?

The course of MS is different from one person to the next, and can be mild, moderate, or severe.

The nature of someone's MS only becomes apparent over time and under normal circumstances it is not possible to say at diagnosis how someone's MS will develop.

The course of MS is often classified into three internationally recognised types, although people's experience of the condition varies so widely that it is not always easily apparent which type of MS they have.

1: Relapsing Remitting (RRMS)

At diagnosis, the majority of people have this form of MS - relapses (also known as attacks or exacerbations) occur on average once or twice a year, with good or complete remission in between, but with a tendency for symptoms to persist or increase over time.

This is the most common form of MS at time of initial diagnosis. It affects approximately 85% of everyone diagnosed with MS.

Some people with Relapsing Remitting MS have a type of MS which is known as rapidly evolving severe relapsing-remitting MS (RES). This can also be known as highly active RRMS. This is defined by having two or more disabling relapses in one year and disease activity shown up on an MRI scan.

2: Secondary Progressive (SPMS)

People with this type of MS experience an initial period of relapsing remitting disease, (see above) but this is followed by a steadily worsening disease course with or without occasional flare-ups, minor recoveries (remissions), or plateaus.

The majority of people with the RRMS, but not all, will eventually develop SPMS; however the time taken varies enormously. After 10 years, 50% of people with RRMS will have developed SPMS. By 25 to 30 years, that figure will have risen to 90%.

3: Primary Progressive (PPMS)

People with this type of MS experience a slow but steady worsening of their disease ('progression') from the start, with no distinct relapses or remissions. But there are variations in speed at which it progresses. There are also occasional plateaus and temporary minor improvements.

This type of MS is relatively rare - only about 15% of people with MS will get this form.

Benign MS

Benign MS is not a 'type' of MS, as such, but in some cases, people experience very occasional relapses, usually early on, with complete recovery - or remission - in between. They don't have any serious disability and further relapses are infrequent - in fact they can sometimes happen a number of years apart. These people are said to have 'benign' MS. By its nature, benign MS can only be diagnosed after a long period of time with little disease activity. Estimates on how many people with MS turn out to have benign MS vary, but range from 5 - 20%.