MS flare-ups are typically treated with a short course of high-dose corticosteroids, usually given over three to five days. This is the standard first-line approach for relapses that cause significant new or worsening symptoms. But treatment also involves figuring out whether you’re having a true relapse or something that mimics one, managing your specific symptoms, and understanding what recovery looks like.
True Relapse vs. Pseudo-Relapse
Before starting treatment, it’s important to distinguish between a genuine flare and a pseudo-relapse. A true relapse involves a new neurological symptom, or the return and worsening of an old one, that lasts longer than 24 to 48 hours and isn’t caused by something else. A pseudo-relapse looks and feels similar but is triggered by temporary stressors that raise your core body temperature or tax your body. Once the trigger is removed, the symptoms resolve.
Common pseudo-relapse triggers include fever, infections, hot showers, sun exposure, intense exercise, psychological stress, hormonal shifts during the menstrual cycle, and even cigarette use. This temperature-related worsening is called the Uhthoff phenomenon. The key difference is timing: pseudo-relapse symptoms appear quickly after a known trigger and fade just as quickly, while true relapse symptoms tend to develop gradually over hours or days and persist. If an underlying infection is driving your symptoms, treating the infection is the priority, not steroids.
High-Dose Corticosteroids
For a confirmed relapse causing meaningful disability, the standard treatment is high-dose corticosteroids for three to five days. This is most commonly given as an intravenous infusion once daily for each of those days. You’ll typically receive this at an infusion center, though some neurologists arrange home infusions. If IV treatment isn’t practical, an oral steroid course over the same three-to-five-day window is an alternative. The goal of steroids isn’t to cure the relapse. They shorten the duration of the flare by reducing the inflammation attacking your nerve fibers, helping you recover faster than you would on your own.
Steroids come with side effects you should be prepared for. Common ones include insomnia, a metallic taste in your mouth, mood changes (including irritability or anxiety), increased appetite, fluid retention, and elevated blood sugar. These are temporary and typically resolve within days to a couple of weeks after finishing the course. Your doctor may prescribe a sleep aid or suggest taking the infusion early in the day to help with the insomnia.
When Steroids Don’t Work
If a severe relapse doesn’t improve after corticosteroids, plasma exchange is the best-supported second-line option. The American Academy of Neurology recommends considering it for severe flares in relapsing forms of MS. During plasma exchange, blood is drawn from your body, the liquid portion (plasma) is separated and replaced with clean plasma, and the blood is returned. The idea is to remove the harmful immune proteins in your plasma that are attacking your nervous system. This typically involves a series of treatments over one to two weeks.
Plasma exchange is reserved for relapses with serious consequences, such as inability to walk or significant vision loss, that haven’t responded to steroids. It is not effective for progressive forms of MS. Another less commonly used option is a hormone injection (ACTH gel) given by intramuscular or subcutaneous injection daily for two to three weeks. This is FDA-approved for acute MS exacerbations and works by stimulating your body’s own cortisol production. Intravenous immunoglobulin is sometimes used in exceptional cases where steroids are contraindicated and the relapse is severe, but the evidence supporting it is limited.
Rehabilitation During Recovery
Steroids address the inflammation, but rehabilitation addresses the functional damage. Physical and occupational therapy are considered an integral part of relapse management, not an afterthought. Cleveland Clinic, for example, engages patients with a multidisciplinary team focused on both physical and emotional wellbeing during and after treatment for a relapse. Depending on your symptoms, this might mean working with a physical therapist on balance and walking, an occupational therapist on fine motor tasks and daily activities, or a speech therapist if you’re experiencing swallowing or speech difficulties.
Starting rehabilitation early, while you’re still recovering, gives you the best chance of regaining function. Your therapist can also help you distinguish between safe fatigue from exercise and warning signs that you’re pushing too hard, which is especially important given the temperature sensitivity many people with MS experience.
What Recovery Looks Like
Recovery from a flare doesn’t always mean returning to exactly where you were before. A large meta-analysis found that roughly 42% of relapses result in incomplete recovery, meaning some residual disability remains at six months or beyond. That still means the majority of relapses do resolve fully or nearly fully, especially with prompt treatment. But the statistic underscores why reducing the number of relapses through disease-modifying therapy is such a priority in MS care.
The timeline varies widely. Some people feel noticeably better within days of starting steroids, while others improve gradually over weeks or even a few months. Symptoms that appeared during the flare may linger at a lower intensity for some time before fully clearing. There’s no reliable way to predict how completely any individual relapse will resolve, but early treatment with steroids is associated with faster recovery.
Symptoms That Need Immediate Attention
Most flare-ups are managed through your neurologist’s office, but certain situations call for more urgent care. If your symptoms are severe enough to significantly impair your function, particularly if you can’t walk or have lost vision in an eye, it may make sense to go directly to emergency care rather than waiting for a clinic appointment. The National MS Society also emphasizes distinguishing between a relapse and a stroke: stroke symptoms hit within seconds and peak within minutes, while MS relapse symptoms develop gradually over hours or days.
You should also seek immediate care if you develop signs of a serious infection during a flare, including high fever, confusion, shortness of breath, or a drop in oxygen levels. People with MS who develop infections can become septic, with the infection spreading into the bloodstream and causing worsening neurological symptoms alongside systemic illness. Falls during a flare, especially any that involve a head injury, also warrant emergency evaluation regardless of whether you lost consciousness.