Lipedema is a condition that causes an abnormal buildup of fat cells in the legs, thighs, and buttocks. It typically affects women and causes enlargement or swelling in the lower body. While the exact cause is unknown, lipedema is thought to be caused by a hormonal disorder that leads to abnormal distribution of fat cells. The swelling is symmetrical, meaning it occurs in both legs. In addition to swelling, lipedema causes the skin to feel soft or doughy. The fat buildup associated with lipedema is resistant to diet and exercise. One way doctors test for lipedema is with a “pinch test”.
What is the pinch test?
The pinch test is a simple diagnostic technique doctors use to check for lipedema. To perform a pinch test, the doctor pinches the skin and tissue in different areas of the body, usually the arms and legs. The doctor compares the thickness and texture of the pinched skin in the arms versus the legs. With lipedema, there is noticeable thickening and enlargement in the lower body compared to the upper body. The tissue in the legs feels soft, doughy, and cushiony when pinched. Whereas tissue pinched in the arms feels firm and resilient.
With lipedema, the lower body enlargement is symmetrical, meaning both legs are equally affected. Doctors will pinch multiple areas of both legs and arms to compare tissue texture. This allows them to determine if there is a distinct difference between the upper and lower body consistent with lipedema. The pinch test helps distinguish lipedema fat from regular body fat. While overweight people carry excess fat all over, lipedema specifically causes fat to accumulate in the legs and lower body.
How is the pinch test performed?
To perform the pinch test, the doctor pinches the tissue between their thumb and index finger. They apply a small amount of pressure, enough to grasp the skin and fat underneath without causing discomfort or pain. Typically, they will pinch the back of the upper arm first as a point of comparison for normal tissue. Then, they will pinch multiple areas of the legs such as:
- Front of the thigh
- Side of the thigh
- Back of the thigh
- Calf
- Ankle
As they pinch each area, they evaluate the thickness, texture, and feel of the tissue. With lipedema, the tissue feels disproportionately soft, puffy, and enlarged compared to the arms. The doctor also looks for tenderness or pain during the pinch test, which can occur with lipedema. They may ask the patient to rate any pain or discomfort on a scale of 1-10 while pinching. The pinch test helps determine if swelling and enlargement in the legs is isolated and symmetrical, rather than occurring all over the body evenly.
Results of the pinch test
If a patient has lipedema, the pinch test will show:
- The tissue in the legs feels thicker and more padded compared to the arms
- The tissue has a soft, doughy texture when pinched
- There may be tenderness or pain when tissue is pinched
- The swelling and enlargement is symmetrical in both legs
With normal fat distribution or obesity, the tissue texture feels similar throughout the body. With lipedema, there is a distinct tissue quality isolated to the lower body. The pinch test can help distinguish lipedema fat from lymphedema fluid swelling. With lymphedema, tissue feels firm or stiff rather than soft when pinched due to fluid buildup.
The pinch test cannot definitively diagnose lipedema on its own. But it provides helpful information for doctors to determine if further testing for lipedema is warranted. It is often used along with patient history, a physical exam, and imaging studies to reach a lipedema diagnosis. If the pinch test indicates possible lipedema, additional tests like an ultrasound or MRI may be ordered to confirm.
Why is the pinch test important?
The pinch test serves a few important purposes:
- It helps doctors screen for lipedema by feeling for characteristic tissue changes in the legs
- It helps distinguish between lipedema fat and regular body fat
- It helps differentiate lipedema from other conditions like lymphedema or obesity
- It establishes if swelling and enlargement in the legs is symmetrical as seen in lipedema
- It determines if tissue is tender, which can indicate lipedema
Without a simple diagnostic test like the pinch test, lipedema can be mistaken for obesity or other disorders. Lipedema is often misdiagnosed, so the pinch test provides valuable information to doctors. Catching lipedema early allows for better management with treatments like liposuction, compression, massage, and counseling. The pinch test helps avoid delays in diagnosis so patients can get the help they need.
Limitations of the pinch test
While the pinch test is useful for screening, it does have some drawbacks and limitations:
- Results can vary between practitioners performing the test
- It relies on subjective evaluation of tissue texture which is not perfectly quantifiable
- It cannot definitively diagnose lipedema on its own without other testing
- Some patients have tender subcutaneous tissue even without lipedema
- Other fat disorders like Dercum’s disease can have similar tissue findings
Due to these limitations, the pinch test should not be used as the sole diagnostic tool for lipedema. However, it remains an accessible, inexpensive, and rapid screening method when combined with a full clinical workup. It can prompt further testing like imaging in cases where lipedema is suspected based on pinch test results.
Who performs the pinch test?
The pinch test is typically performed by doctors as part of diagnosing lipedema. Physicians who may use the pinch test include:
- General practitioners
- Internists
- Rheumatologists
- Dermatologists
- Vascular specialists
- Plastic surgeons
- Lymphedema specialists
Any doctor evaluating a patient for possible lipedema will likely perform a pinch test. It can be done in an outpatient clinic or doctor’s office. Some doctors may refer patients to lymphedema therapists who also commonly use the pinch test during lipedema evaluations.
While useful as an initial screening, doctors should not rely solely on pinch test findings to definitively diagnose lipedema. A full clinical workup is needed. But the pinch test provides key clues that can prompt further specific testing for lipedema.
Conclusion
The pinch test is a simple yet valuable technique doctors use to screen for lipedema. By pinching the tissue in the arms and legs and comparing texture, thickness, and tenderness, doctors can gain clues about whether lipedema fat may be present. It helps determine if lower body swelling is isolated and symmetrical as seen in lipedema. While not definitive on its own, the pinch test can prompt doctors to pursue more specific lipedema testing like imaging studies. Early screening helps patients get the proper treatment and prevent progression of lipedema. When combined with a full clinical evaluation, the pinch test improves detection of this often misdiagnosed lipoedema.
