What is DSLD / ESPA?
Degenerative Suspensory Ligament Disease (DSLD), more accurately termed Equine Systemic Proteoglycan Accumulation (ESPA), is a chronic, progressive condition that affects connective tissues throughout the body.
While it’s most commonly recognized as a disease of the suspensory ligaments, it is not just a ligament injury. Instead, it involves abnormal accumulation of proteoglycans (a type of structural molecule) within connective tissues. Over time, this leads to weakening and loss of normal elasticity.
In practical terms:
This is not a strain that heals—it’s a systemic condition that gradually changes how the horse’s body supports itself.
What horses are affected?
DSLD/ESPA has been identified in multiple breeds, including:
- Peruvian Pasos (most commonly recognized)
- Warmbloods
- Quarter Horses
- Arabians
- Draft breeds and crosses
We are recognizing it more frequently across a wider range of horses than previously thought.
There is strong evidence suggesting a genetic component, although the exact inheritance pattern is still being studied.
What are the clinical signs?
Signs can be subtle early on and often progress over time. Common things owners notice include:
Early signs:
- Mild or intermittent lameness
- Stiffness, especially when first coming out of the stall
- Reduced performance or unwillingness to engage
Progressive changes:
- Dropping of the fetlocks (especially in hind limbs)
- “Sinking” appearance at the ankle
- Difficulty with collection or impulsion
- Shortened stride
Advanced stages:
- Significant fetlock hyperextension
- Reluctance to move
- Secondary soreness in other areas (back, SI, compensatory limbs)
Because this is a systemic disease, other tissues (such as tendons, ligaments, and even skin or sclera) may also be affected, though these changes are less obvious.
How is DSLD/ESPA diagnosed?
Diagnosis is typically based on a combination of:
- Physical exam findings
- Lameness evaluation
- Ultrasound of the suspensory ligaments
Ultrasound often shows diffuse, characteristic changes rather than a focal injury pattern.
In some cases, diagnosis is supported by:
- Biopsy (less commonly performed in practice)
- History and progression of signs
Is there a cure?
At this time, there is no cure for DSLD/ESPA.
This is one of the hardest parts of the diagnosis, but it’s important to be clear:
This condition is managed, not reversed.
What does management look like?
The goal shifts from “fixing the problem” to supporting comfort, function, and quality of life.
A thoughtful management plan often includes:
1. Farriery
- Corrective trimming and shoeing to support the limb
- Often focused on reducing strain on the suspensory apparatus
2. Controlled exercise
- Light, consistent movement tends to be better than full rest
- Avoid overloading affected structures
3. Medical support
- NSAIDs (as needed for comfort)
- Joint support therapies when indicated
- In some cases, regenerative therapies may be considered, though results are variable
4. Supportive therapies
This is an area where we often focus early:
- Acupuncture
- Dry needle therapy (DNT)
- Laser therapy
- Bodywork and rehab exercises
These therapies don’t change the underlying disease, but they can help maintain comfort and function for longer.
What is the long-term outlook?
DSLD/ESPA is a progressive condition, but the rate of progression varies significantly between horses.
Some horses remain comfortable for years with appropriate management. Others progress more quickly.
Key factors that influence outcome include:
- Severity at diagnosis
- Workload and expectations
- Hoof balance and support
- Early intervention and consistent management
Over time, many horses will need to transition out of athletic work, and in advanced cases, quality of life decisions may need to be made.
What should you do after a diagnosis?
If your horse has just been diagnosed, the most important next steps are:
- Establish realistic goals for your horse’s future
- Build a management plan early
- Stay consistent—this condition rewards steady, thoughtful care
And just as importantly:
Give yourself some space to process it. This is not a small diagnosis, and it’s okay for it to take time to adjust expectations.
In Conclusion
DSLD/ESPA is a complex condition that challenges both horses and their owners. While we can’t cure it, we can support these horses in meaningful ways—keeping them comfortable, functional, and enjoying life for as long as possible.
If you have questions about your horse’s specific case or want help building a management plan, we’re always here to help.
