Case Report · The Fascia Institute
A wasp sting, the fascia, and an unusual path to relief
Six weeks after a wasp sting, a hypermobile, pregnant patient still had a quarter-sized patch of forearm pain that tightened every time she moved her wrist. The answer wasn’t in the skin or the nerve — it was in the fascia. Here is her case, the ultrasound that found it, the ultrasound-guided hydrodissection that resolved it, and the science of why this happens.
Jacques Courseault, MD, CAQSM, FAAPMR · The Fascia Institute and Treatment Center®
· Fascial Hydrodissection · Mast Cells · Hypermobility · Ultrasound-Guided
Patient
34-year-old female, hypermobile, 6 months pregnant
Presentation
Persistent forearm pain 6 weeks after a wasp sting; tightness with wrist motion
Intervention
Ultrasound-guided fascial hydrodissection (Butterfly IQ+)
Outcome
Near-immediate relief of tightness and pain; no complications
01 · Presentation
A sting that wouldn’t stop hurting
A 34-year-old woman who is hypermobile and six months pregnant came to The Fascia Institute after being stung by a wasp on the right forearm six weeks earlier. Her initial reaction was dramatic — severe inflammation running along the forearm — but it settled within about a week. What didn’t settle was the pain.
At the sting site, a persistent, tender area about the size of a quarter remained. Bending the wrist into flexion produced tightness and pain at the spot; extending the wrist created a distinct pulling sensation there. Since that first week, she’d had no further swelling, and denied fevers, chills, or any other sign of infection. Her pregnancy had been uncomplicated. In short: the acute reaction was long over, yet a small, mechanically-provoked pain had stubbornly stayed behind.
The persistent wasp-sting site on the right forearm. · The Fascia Institute and Treatment Center
02 · Evaluation
Point-of-care ultrasound found what exam alone couldn’t
Because the story was unusual — a mechanical pain long outlasting an insect sting — we went looking for a fascial cause rather than assuming a lingering skin or soft-tissue reaction. The patient pointed to her area of tenderness, and using a handheld Butterfly IQ+ ultrasound we scanned it in real time. The imaging localized the problem precisely: a focal area of fascial change and inflammation, right where her symptoms lived.
Ultrasound of the sting site (Butterfly IQ+): focal fascial thickening and inflammation corresponding to the point of pain. · The Fascia Institute and Treatment Center
Why imaging mattered here
Ultrasound let us see a fascial abnormality that a physical exam alone would likely have missed — and it told us the pain generator was a restricted fascial plane, not the nerve, joint, or skin. That distinction is what pointed to the right treatment.
03 · Intervention
Fascial hydrodissection — separating what had stuck together
Given the focal fascial adhesion and inflammation, we performed an ultrasound-guided fascial hydrodissection around the sting site: using imaging to guide the needle, fluid is injected precisely between the bound fascial layers to gently separate them and restore their normal glide. Because the fluid can be simple saline or dextrose, the procedure is drug-sparing — an important consideration for a pregnant patient — and every step is watched live on ultrasound for safety.
The response was fast. Almost immediately, the tightness with wrist flexion and the pulling with extension were gone, and the chronic, quarter-sized area of pain was substantially reduced.
The Trigger
Venom in the fascia
The sting deposits venom between fascial planes, triggering an intense, mast-cell–driven local inflammation.
The Problem
Layers adhere
As it heals, poorly-perfused scar and adhesion bind the layers together, so the fascia can’t glide — hence pain with wrist motion.
The Release
Hydrodissection
Ultrasound-guided fluid separates the planes and restores glide — often, as here, with immediate relief.
Educational illustration · The Fascia Institute and Treatment Center
04 · Discussion
Why an odd injury turned out to be fascial
Unusual, hard-to-explain musculoskeletal pains are often fascial in origin — because fascia is a richly innervated, living tissue, not inert wrapping. Two features of this case make the fascial explanation especially compelling.
Fascia is full of mast cells. Histology shows mast cells distributed throughout human fascia — among the collagen bundles, near vessels, and close to the nerves that cross it (Detection of Mast Cells in Human Superficial Fascia, 2023). When those mast cells degranulate, they release histamine, proteases, and inflammatory cytokines that drive swelling, recruit immune cells, and sensitize nearby nerves. A wasp sting is essentially a direct injection of venom that sets off exactly that mast-cell cascade — and if the venom lands between fascial planes, the reaction plays out inside the connective-tissue web itself.
Then the fascia heals imperfectly. Some fascial regions are relatively poorly perfused, so after an intense local reaction they can knit down into adhesion or scar rather than healthy, gliding tissue. That adhered plane is what tethered her wrist motion — producing the tightness in flexion and the pulling in extension long after the sting itself was forgotten.
The hypermobility connection
Our patient is hypermobile, and there is a growing (though still-debated) literature linking hypermobility and hypermobile Ehlers-Danlos syndrome with heightened mast-cell reactivity — with one review reporting a majority of hEDS patients also meeting criteria for mast cell activation (Monaco et al., Immunologic Research, 2022). A more reactive mast-cell system may help explain why a routine sting produced such a pronounced, lingering fascial response. It’s an area we study closely — see Dr. Courseault’s commentary on mast cells and the hypermobile body.
Why hydrodissection was the right tool. Once imaging showed an adhesion, the fix is mechanical, not pharmacological. Ultrasound-guided hydrodissection releases perineural and interfascial adhesions and decompresses the tissue, and systematic reviews find it effective and very safe — performed in some protocols with saline alone, with serious adverse events essentially absent (systematic review of ultrasound-guided hydrodissection, 2024). That drug-sparing, image-guided profile made it a sensible, conservative option during pregnancy, chosen through shared decision-making. The technique itself was first described in the literature by Dr. Courseault for chronic hamstring injury and is the foundation of our Hydrofascia Release™ program.
05 · Outcome & Takeaway
A fast resolution, and a lesson worth keeping
The patient did well. With the fascial adhesion released, her mechanical tightness resolved and her chronic pain dropped sharply — and she was able to continue her pregnancy without the nagging forearm pain. As with any single case, this is one patient’s experience and not a guarantee of results, but it illustrates a pattern we see often: when a pain doesn’t fit the usual boxes, the fascia is worth investigating.
The takeaway
Strange, persistent, mechanically-provoked pain — especially in a hypermobile patient — deserves a look at the fascia with ultrasound. The problem is frequently a restricted plane that hands-on exam can’t see, and that a precise, drug-sparing hydrodissection can release.
References & Further Reading
1. Detection of Mast Cells in Human Superficial Fascia. Int J Mol Sci. 2023. — PMC
2. Monaco A, et al. Association of mast-cell-related conditions with hypermobile syndromes: a review of the literature. Immunol Res. 2022. — Springer
3. Safety and Efficacy of Ultrasound-Guided Perineural Hydrodissection as a Minimally Invasive Treatment in Carpal Tunnel Syndrome: A Systematic Review. 2024. — PMC
4. Courseault J, et al. Fascial Hydrodissection for Chronic Hamstring Injury. Curr Sports Med Rep. 2019. — PubMed
5. The Fascia Institute — What is a Fascial Hydrodissection / Hydrorelease?
This is a single, de-identified patient case shared for education; individual results vary and this is not medical advice, nor does it create a physician–patient relationship. Any procedure during pregnancy is individualized through shared decision-making with your physicians. The Fascia Institute and Treatment Center® · 2520 Harvard Ave, Ste 2B, Metairie, LA 70001 · (504) 704-1254.
