Relapse or Flare - spot the difference

Hi Everyone,

I’m still trying to figure out this bloody illness and wondered whether you can help. I started a relapse in April / May and began Ocrevus infusions in July / August (my first DMT). This caused a temporary flare, followed by a a period of symptoms coming and going in waves. I was treated with antibiotics a couple of weeks ago for a possible UTI (they didnt test it as i was shielding following the ocrevus infusions) but i still have lower back pain, soreness in the kidney region. Maybe there is still an underlying infection, who knows. The last couple of days my symptoms (mainly sensory) have definitely been on the rise. I’m hopeful this is not the start of another relapse as i still don’t feel like i have come out of the last one. It is mentally tiring just feeling ill everyday and not knowing whether it will improve.

I suppose my main question is - what is the difference between a flare and a relapse. For instance, if i do have a UTI this could cause my symptoms to rise (a flare?) but this would not necessarily be a relapse (i.e no more damage). Is this correct?

Thanks for any help that you can give


Personally, I hate the word ‘flare’ when associated with MS. To my mind, a flare is a relapse and you might just as well call it that. That’s what the MS Trust say too - see

Although, a UTI should be checked out as you can have all the indications of a relapse when you have a UTI. I would suggest always getting a potential UTI checked out because it needs to have the lab identify exactly which bacteria are causing the infection so the appropriate antibiotics can be prescribed. So wherever/whenever possible, if you think you have an infection, get it checked.

I would perhaps call the symptoms of a relapse caused by an infection a pseudo-relapse rather than confuse matters with other names for it.

In your situation, as it’s now the weekend and impossible to get your urine checked until Monday, drink plenty of water over the weekend, rest as much as you’re able, and plan on getting a sample to your GP surgery on Monday.

Best of luck


Thanks Sue. I actually have a GP appointment on Monday so will raise it then. He could be in for a long morning and its in the flesh so no escape! i have had similar pseudo-relapse like symptoms after both ocrevus infusions so its been a bumpy few months…

Shame UTI getting you down. I always thought flare up and relapse the same. Would like someone to find out. And I hope you get better soon.

agree, I thought flare up and relapse were one and the same - that is old symptoms re-appearing. An attack is when a previously unaffected bit of us is affected - not explaining this very well !

Same goes for me a flare up = relapse.

Hopefully it’s just a UTI so get that checked. MS nurses will ask you to do that before they’ll view it as a relapse. I usually get my GP surgery to test mine and give me a call to confirm it before they send it of to the lab…assuming it’s an infection. When it’s not an infection I contact my nurses and after I tell them I think I’m relapsing I then tell them it’s not a UTI has I’ve had that checked.

Much better than then having to wait and contact them again. Always have a sample bottle at home ready for when needed.

Hi, yes all this terminology is confusing. I was thinking relapse and flare same but don’t like pseudorelapse term as makes me feel like I’m being told I’m pretending. Had UTI was earlier this year which wasn’t obvious, just woke up and wonky walking had deteriorated to legs totally collapsing under me, very scary few days but thankfully fixed by antibiotics for UTI. Was so relieved not another relapse but felt just as bad at the time. Good luck. Froo x