Key Takeaways
- Common side effects (soreness, redness, mild swelling) occur in 10-30% of patients and resolve within 72 hours
- Serious complications like tendon rupture are extremely rare with no established causal link to ESWT in systematic reviews
- A temporary "worse before better" flare-up in the first 24-72 hours is normal and consistent with the intended healing response
- Avoid NSAIDs for 48-72 hours after treatment -- they may blunt the inflammatory cascade that drives tissue repair
- Contact your provider if pain is substantially worse than baseline, numbness persists beyond a week, or signs of infection appear
You’ve booked your first shockwave therapy session – or maybe you’ve already had one and something doesn’t seem right. Either way, you want to know: what side effects are normal, which ones are cause for concern, and when should you actually call your provider?
This article is distinct from our guide on whether shockwave therapy hurts during treatment. That article covers the in-session experience. This one focuses on clinical side effects – the things that happen in the hours and days after you leave the treatment room.
Common Side Effects (Expected in 10-30% of Patients)
These side effects occur regularly and are considered a normal part of the treatment response. They do not require medical attention unless they are unusually severe or prolonged:
Localized soreness and tenderness. The most common side effect. The treated area may feel sore, achy, or tender to the touch – similar to what you’d feel after an intense deep-tissue massage or a hard workout. This soreness typically begins within a few hours of treatment and peaks at 24 to 48 hours. It generally resolves within 72 hours.
Skin redness (erythema). The skin over the treated area often turns pink or red during and after treatment. This is caused by increased blood flow to the area – part of the intended therapeutic response. Redness usually fades within a few hours, though it can persist for up to 24 hours in some patients.
Mild swelling. Slight puffiness or swelling around the treatment site is common, particularly when treating tendons near the surface (Achilles, lateral elbow). This inflammatory response is actually part of how ESWT works – the treatment triggers a controlled inflammatory cascade to stimulate healing. Mild swelling typically resolves within 24 to 72 hours.
Petechiae and bruising. Small, pin-point red dots (petechiae) or broader bruising can occur at the treatment site, especially in areas with superficial blood vessels or thin skin. Patients on blood-thinning medications or supplements (aspirin, fish oil, vitamin E) may be more prone to bruising. Bruises typically resolve within 1 to 2 weeks.
Uncommon Side Effects
These effects are less frequent but are recognized in clinical literature:
Temporary numbness or tingling. Some patients report a temporary decrease in sensation or a tingling feeling in the treated area. This is typically related to the intense stimulation of nerve endings during treatment and usually resolves within hours to a few days. If numbness persists beyond a week, contact your provider.
Skin irritation at the treatment site. Occasional redness, warmth, or a mild rash at the point of contact with the shockwave applicator. This may be related to the coupling gel, the pressure of the applicator, or a skin sensitivity response. It usually clears within 24 to 48 hours. Patients with known skin sensitivities should inform their provider before treatment.
Temporary worsening of symptoms. A subset of patients experience a brief flare-up of their original symptoms in the 24 to 72 hours following treatment. This “worse before better” pattern is consistent with the inflammatory healing response that ESWT triggers. If the flare persists beyond 5 to 7 days or is significantly worse than your baseline pain, contact your provider.
Rare Complications
These adverse events are rare in the published literature but are important to understand:
Tendon rupture. The most discussed rare complication. Isolated case reports exist describing tendon rupture following ESWT treatment. However, it is debated whether ESWT caused the rupture or whether the rupture occurred in a tendon that was already severely degenerated and at risk. A 2020 systematic review found no established causal relationship between ESWT and tendon rupture when treatment is performed within standard energy parameters (Schmitz et al., 2015, International Journal of Surgery). The risk appears to be extremely low – well under 1% in clinical trials.
Persistent worsening of symptoms. In a small percentage of patients, symptoms may worsen after ESWT and not return to baseline. This is uncommon but underscores the importance of accurate diagnosis before treatment. If shockwave therapy is applied to a misdiagnosed condition – for example, treating what is believed to be tendinopathy but is actually a nerve entrapment – the treatment may aggravate the actual problem.
Soft tissue damage. When ESWT is applied incorrectly (excessive energy levels, inappropriate treatment location), it can theoretically cause damage to surrounding soft tissue structures. This is rare with trained providers following evidence-based protocols.
Side Effect Timeline
Here is what to expect in the typical post-treatment window:
| Timeframe | What’s Normal | Contact Your Provider If… |
|---|---|---|
| 0-4 hours | Redness, warmth, mild soreness | Severe or sharp pain that was not present before treatment |
| 4-24 hours | Increasing soreness, mild swelling, possible petechiae | Significant swelling, numbness that doesn’t resolve, skin breakdown |
| 24-72 hours | Peak soreness (then gradual improvement), bruising may appear | Pain that is substantially worse than your original condition |
| 3-7 days | Soreness resolving, bruising fading | Persistent numbness, increasing swelling, any signs of infection (fever, heat, pus) |
| 1-2 weeks | All side effects should be resolved or resolving | Any new symptom that wasn’t present before treatment |
Absolute Contraindications: When ESWT Should NOT Be Used
Certain conditions make shockwave therapy inappropriate regardless of the target condition. Your provider should screen for these before treatment:
- Over open growth plates – in children and adolescents whose bones are still developing, ESWT near growth plates could potentially affect bone growth
- Over malignant tumors – mechanical stimulation could theoretically promote tumor growth or metastasis
- Pregnancy – ESWT should not be applied near the uterus or fetus
- Blood clotting disorders – conditions or medications that impair clotting increase the risk of significant bruising or bleeding
- Active infection in the treatment area – mechanical stimulation of infected tissue could worsen the infection or spread it
- Over areas with metallic implants – depending on the device type and energy level, some implants may be a contraindication (discuss with your provider)
For a comprehensive guide on who should avoid shockwave therapy, see our article on shockwave therapy contraindications. Qualified providers should perform thorough screening before every treatment session.
Minimizing Side Effects
While side effects cannot be eliminated entirely, several strategies can reduce their likelihood and severity:
- Communicate during treatment. Tell your provider when pain intensity exceeds your tolerance. Energy levels can be adjusted in real time.
- Disclose all medications. Blood thinners, anticoagulants, and even supplements like fish oil and vitamin E increase bruising risk. Your provider may adjust the protocol accordingly.
- Avoid NSAIDs before and after treatment. Anti-inflammatory medications may reduce the therapeutic inflammatory response that ESWT relies on. Most providers recommend stopping NSAIDs 48 to 72 hours before treatment and for at least 48 hours after.
- Follow post-treatment instructions. Activity modification in the 24 to 48 hours after treatment helps the treatment area recover appropriately.
- Attend all scheduled sessions. Protocols are designed as a series. Skipping sessions or stopping early may reduce the cumulative benefit.
The Bottom Line
Shockwave therapy has a well-established safety profile. The vast majority of side effects are mild, temporary, and resolve within days. Serious complications are rare, particularly when treatment is performed by a qualified provider following evidence-based protocols and appropriate screening. Understanding what is normal – and what warrants a call to your provider – helps you approach treatment with informed confidence rather than unnecessary anxiety.
References
- Schmitz C, Császár NB, Milz S, et al. Efficacy and safety of extracorporeal shock wave therapy for orthopedic conditions: a systematic review on studies listed in the PEDro database. Br J Sports Med. 2015;49(9):590-595. PubMed
Medical Disclaimer: This content is for informational purposes only and does not constitute medical advice. Shockwave therapy outcomes vary by individual and condition. Consult a qualified healthcare provider to determine if shockwave therapy is appropriate for your situation.