MS flare-ups are typically treated with a short course of high-dose steroids, usually given over three to five days. This doesn’t cure the flare, but it shortens its duration and reduces the intensity of symptoms. For every 1,000 people with MS treated with steroids during a relapse, about 247 more will improve compared to those given a placebo. Without treatment, more than 40% of patients are left with lingering deficits nine weeks after a relapse.
True Flare vs. Pseudo-Relapse
Before starting treatment, it’s important to figure out whether you’re experiencing a true relapse or a pseudo-relapse. A true MS relapse involves new or worsening neurological symptoms that last at least 24 hours and aren’t explained by another cause like infection or fever. A pseudo-relapse, on the other hand, is a temporary worsening of existing symptoms triggered by physical stress on the body. Once the trigger resolves, symptoms typically subside within 24 hours.
Common pseudo-relapse triggers include urinary tract infections, other infections that cause fever, overheating (sometimes called Uhthoff’s phenomenon), and emotional stress. If an infection is the culprit, treating it with antibiotics and bringing down the fever with over-the-counter pain relievers like acetaminophen is usually enough. People with heat-sensitive MS often benefit from cooling vests or simply avoiding hot tubs, saunas, and prolonged heat exposure. The key distinction: pseudo-relapses don’t need steroid treatment because the underlying MS hasn’t actually worsened.
High-Dose Steroids: The First-Line Treatment
When a true relapse is confirmed, the standard treatment is high-dose methylprednisolone. The typical regimen is 500 to 1,000 mg per day for three to five days, with a median treatment duration of about four days. This can be given intravenously at an infusion center or hospital, or increasingly as a high-dose oral formulation that you take at home.
Both routes appear to work similarly. Intravenous infusions are sometimes preferred when symptoms are severe, when oral steroids haven’t worked or aren’t tolerated, or when hospitalization is needed to monitor other conditions like diabetes or depression. Oral methylprednisolone offers the convenience of home administration, which many patients prefer. Your neurologist will help decide which route makes sense based on your situation and symptom severity.
The goal of steroid treatment isn’t to reverse the relapse entirely. It’s to shorten how long the flare lasts and reduce its intensity, giving your body a head start on recovery.
Side Effects of Steroid Treatment
High-dose steroids are effective, but they come with noticeable short-term side effects. In studies tracking patient-reported experiences, the most common complaints were a metallic or altered taste (affecting about 61% of patients), facial flushing (61%), nausea or stomach pain (53%), sleep disturbance (44%), appetite changes (37%), and agitation (36%). Behavioral and mood changes, including feeling unusually irritable or overoptimistic, affected about a third of patients.
Among those who rated their side effects as severe, sleep disturbance topped the list at 31%, followed by muscle weakness (22%), stomach pain (20%), and agitation (19%). These effects are temporary and generally resolve after the steroid course ends, but they can make an already difficult few days harder. Knowing what to expect helps. If you have a history of insomnia, mood disorders, or stomach problems, mention it to your neurologist beforehand so the treatment plan can be adjusted.
When Steroids Don’t Work
About 20% to 35% of people with MS don’t respond adequately to high-dose steroids during a relapse. When the first round fails, guidelines recommend an additional course of steroids (typically another 2,000 mg total). If symptoms still persist after that second attempt, the relapse is classified as steroid-resistant, and treatment escalates to other options.
Plasma exchange (also called plasmapheresis) is the most established second-line treatment. It works by filtering the blood to remove the antibodies and inflammatory proteins that are attacking the nervous system. In clinical practice, the median time from relapse onset to starting plasma exchange is about seven weeks, reflecting the time needed to try steroids first and confirm they’ve failed.
Another FDA-approved option for steroid-refractory relapses is repository corticotropin injection (sold as Acthar Gel). This is a different type of treatment that stimulates the body’s own anti-inflammatory pathways. In clinical trials, patients who didn’t respond to high-dose steroids received daily injections for 14 days, with evidence suggesting it can help where steroids alone could not.
Managing Symptoms During a Flare
While steroids address the underlying inflammation, you may still need to manage specific symptoms as they occur. A flare can affect nearly any function depending on where the new inflammation is happening: vision, balance, bladder control, sensation, strength, or cognitive clarity. The approach is practical. If an infection is suspected as a contributing factor, treating it promptly and managing any fever is a priority, since even a slight temperature increase can amplify MS symptoms.
Rest plays a real role during an active flare. Your nervous system is under acute stress, and pushing through can prolong recovery. That said, complete immobility isn’t the goal either. Gentle movement, when tolerated, helps maintain circulation and prevents the deconditioning that makes recovery harder.
Rehabilitation After a Flare
Not every relapse requires formal rehabilitation, but for those left with residual symptoms after the acute phase, physical and occupational therapy can make a meaningful difference. Multidisciplinary rehab programs focus on regaining function, developing strategies to work around any remaining deficits, and reducing the risk of long-term disability.
In studies examining post-relapse rehab, participants entered programs anywhere from shortly after their flare to five months afterward. There’s some concern in the medical community that patients often don’t receive adequate rehabilitation or education about recovery after being discharged from steroid treatment. If your symptoms haven’t returned to baseline after completing steroids, asking your neurologist for a rehab referral is reasonable. Therapy goals can range broadly, from improving walking ability and reducing fatigue to strategies for returning to work.
Preventing the Next Flare
A flare-up is also a signal to reassess your disease-modifying therapy (DMT). Any clinical relapse, or the appearance of new lesions on MRI even without symptoms, is considered a sign that your current therapy may not be controlling the disease well enough. Cleveland Clinic’s MS center notes that both clinical relapses and radiographic changes (new lesions on brain or spinal cord imaging) indicate a suboptimal treatment response.
There’s no single agreed-upon threshold for when to switch therapies, but the general principle is straightforward: if you’re having breakthrough disease activity while on a DMT, that medication isn’t doing its job well enough. Your neurologist may recommend switching to a more aggressive therapy. The concept of “no evidence of disease activity,” which combines the absence of relapses, disability progression, and new MRI lesions, is one benchmark used to evaluate whether a treatment is working, though how strictly it’s applied varies between clinicians.