A cortisone shot delivers a powerful anti-inflammatory medication directly into the inflamed tissue at the bottom of your heel, reducing swelling and pain in the plantar fascia. It works well as short-term relief, with most clinical evidence showing significant pain improvement at four weeks, but that benefit fades after that point. It’s not a first-line treatment and is typically offered after simpler approaches like stretching, ice, and shoe inserts haven’t worked.
How It Reduces Pain
Plantar fasciitis involves thickening and inflammation of the tough band of tissue that runs along the sole of your foot, connecting your heel bone to your toes. When that tissue stays irritated, every step compresses inflamed, swollen fibers against your heel bone, producing that characteristic stabbing pain.
A cortisone shot works by flooding the injection site with a corticosteroid that suppresses the inflammatory process. This shrinks the swollen tissue and quiets the nerve endings firing pain signals. A well-known randomized controlled trial published in The BMJ found that a single injection reduced abnormal thickening of the plantar fascia for up to three months, even though pain relief itself was shorter-lived.
How Quickly Relief Starts
You won’t necessarily walk out of the office pain-free. About half of patients who receive a corticosteroid injection notice improvement within three days, and over 90% feel relief within a week. The injection often includes a local anesthetic that numbs the area immediately, but once that wears off in a few hours, pain can temporarily return or even spike before the steroid kicks in.
Roughly one in five patients experiences what’s called a post-injection pain flare, a brief period where the heel feels worse than before the shot. If that happens to you, expect it to take about a day and a half longer to reach noticeable improvement compared to someone without a flare. The flare isn’t dangerous; it’s a reaction to the needle and the fluid volume injected into a tight space.
How Long the Relief Lasts
This is where expectations need to be realistic. The BMJ trial found that pain relief was statistically significant at four weeks compared to a placebo injection, but by eight and twelve weeks the difference between the steroid group and the placebo group was no longer meaningful. In practical terms, you’re likely looking at roughly one month of noticeably better pain, with a gradual return toward baseline after that.
That window of reduced pain isn’t wasted time, though. The purpose of the shot is often to break the pain cycle long enough for you to do the things that actually fix the problem: consistent stretching, physical therapy, and modifications to footwear or activity. If you get a shot and change nothing else, the pain will likely come back.
Where It Fits in the Treatment Ladder
Current treatment frameworks for plantar fasciitis follow a progression from low-risk to more invasive options. Initial therapies include rest, ice, compression, stretching, and orthotic inserts. These are recommended first because they carry almost no risk and resolve the majority of cases over several weeks to months.
Cortisone injections fall into a middle tier, appropriate when those foundational treatments haven’t provided enough relief after a reasonable trial period. Beyond injections, options for stubborn cases include shockwave therapy, platelet-rich plasma injections, and dry needling. Surgery is a last resort, reserved for cases that resist everything else. Most people never need to go past the first two tiers.
Risks Worth Knowing About
The most talked-about risk is plantar fascia rupture, where the band of tissue partially or fully tears. In one study tracking patients who received corticosteroid injections, 2.4% experienced a rupture, and those patients had received an average of nearly three injections before it happened. A rupture causes sudden, sharp pain and can lead to a different set of long-term foot problems, including changes to your arch.
The other significant concern is heel fat pad atrophy. Your heel sits on a specialized cushion of fat that absorbs shock with every step. Repeated steroid injections can cause this fat pad to shrink or break down. The result is a deep, bruise-like pain in the center of your heel that gets worse on hard surfaces, during high-impact activities, or when walking barefoot. Unlike plantar fasciitis pain, which is usually worst with your first steps in the morning and improves as you warm up, fat pad pain tends to build the longer you’re on your feet. Once the fat pad thins, it doesn’t grow back.
Because of these risks, doctors generally cap injections at three to four per year in the same area. The American Academy of Orthopaedic Surgeons notes there’s no formal maximum, but most providers set that practical limit to protect the surrounding tissue.
Guided vs. Unguided Injections
Some providers use ultrasound imaging to guide the needle to the exact spot, while others inject based on anatomical landmarks and the point of maximum tenderness. A recent meta-analysis comparing the two approaches found that ultrasound-guided injections produced better improvements in mechanical pain tolerance and a greater reduction in plantar fascia thickness at both short and long-term follow-ups. If your provider offers ultrasound guidance, it’s worth choosing, though both methods deliver comparable pain relief on standard pain scales.
What to Expect on the Day
The injection itself takes a few minutes. Your provider will clean the bottom or side of your heel, may apply a numbing spray or inject a small amount of local anesthetic first, and then deliver the corticosteroid with a relatively small needle. The heel is sensitive, so the injection is uncomfortable, but it’s brief. Most people describe a deep pressure followed by a sharp sting.
You can walk afterward, but many providers recommend taking it easy for a day or two. Avoid running or prolonged standing for at least 48 hours to let the medication settle into the tissue. Some soreness at the injection site is normal for the first day. Ice and over-the-counter pain relievers can help if the flare response kicks in. By three to five days out, you should have a clear sense of whether the shot is working.