hEDS vs Fibromyalgia Misdiagnosis: What's the Difference?

Many people living with Hypermobile Ehlers-Danlos Syndrome (hEDS) receive an initial diagnosis of fibromyalgia before their underlying connective tissue disorder is recognized ^[1][2]. Both conditions can cause severe, widespread chronic pain, relentless fatigue, and “brain fog” ^[1][3]. Because there is no single blood test or biomarker for either condition, doctors must rely on clinical symptoms to make a diagnosis ^[4][2].

However, while fibromyalgia is primarily considered a central nervous system disorder related to how the brain processes pain signals, hEDS is a genetic connective tissue disorder that affects the structural integrity of the body ^[5][6]. Understanding the differences can help you advocate for a thorough evaluation and a treatment plan that addresses your specific needs. It is also important to recognize the emotional toll of this diagnostic journey, as patients misdiagnosed with fibromyalgia are sometimes mistakenly told their structural pain is merely stress-related or “in their head.”

Why Misdiagnosis Happens: The Symptom Overlap

The confusion between hEDS and fibromyalgia stems from a significant overlap in how the two conditions feel and appear on a day-to-day basis ^[2][1]. Furthermore, these conditions are not mutually exclusive. It is very common for the chronic mechanical joint pain of hEDS to trigger secondary fibromyalgia, meaning a patient can legitimately have both ^[3][7].

Shared Symptoms
Both conditions frequently involve:

• Widespread chronic pain: Pain that affects multiple areas of the body, often accompanied by deep muscle aching and tenderness ^[1][8].
• Severe fatigue and sleep disturbances: Waking up unrefreshed and feeling exhausted throughout the day ^[1][2].
• Central sensitization: A condition where the nervous system becomes highly reactive, amplifying pain signals. This is a hallmark of fibromyalgia but also plays a major role in the chronic pain of hEDS ^[7][3].

Shared Comorbidities
People with hEDS and those with fibromyalgia often experience similar overlapping conditions, making the clinical picture even more confusing ^[9][10]. These include:

• Gastrointestinal issues, like Irritable Bowel Syndrome (IBS)
• Dysautonomia, such as Postural Orthostatic Tachycardia Syndrome (POTS), causing dizziness and rapid heart rate upon standing
• Migraines and tension headaches
• Mast Cell Activation Syndrome (MCAS), leading to allergy-like reactions

Because doctors often screen for fibromyalgia when a patient presents with chronic pain and fatigue, the underlying hEDS can easily be missed if a structural physical exam is not performed.

Distinguishing Features of hEDS

To differentiate hEDS from fibromyalgia, doctors must look beyond pain and fatigue to identify signs of faulty connective tissue ^[6][11]. Fibromyalgia diagnosis relies on the widespread pain index and symptom severity scores, whereas an hEDS diagnosis requires meeting strict 2017 international criteria focused on joint and tissue characteristics ^[12][5].

Key features that point toward hEDS include:

1. Generalized Joint Hypermobility

While some people with fibromyalgia happen to have flexible joints, generalized joint hypermobility is a mandatory diagnostic requirement for hEDS ^[12][13]. Doctors assess this using the Beighton score, a 9-point physical test that measures the flexibility of your spine, elbows, knees, thumbs, and pinky fingers ^[12][14]. Often, patients don’t realize they are hypermobile, dismissing it as childhood “party tricks” (like being able to bend your thumb to your wrist or W-sitting).

2. Joint Instability and Injuries

Pain in fibromyalgia is generally located in the muscles and soft tissues. In hEDS, pain is frequently driven by mechanical joint instability ^[6][15]. People with hEDS often experience frequent subluxations (partial dislocations) or full dislocations of their joints, sometimes from simple, everyday movements ^[12][11].

3. Systemic Connective Tissue Signs

Connective tissue is found throughout the body. hEDS often presents with distinct skin and tissue features that are absent in typical fibromyalgia ^[6][12]. These include:

• Mild skin hyperextensibility (stretchiness)
• Unexplained stretch marks (striae) without a history of significant weight change
• Atrophic scarring, where scars appear thin, wide, or indented like “cigarette paper”
• Easy and frequent bruising
• Dental crowding and a high, narrow palate
• Piezogenic papules (small, soft bumps on the heels that appear when standing)

4. Family History

Because hEDS is a heritable genetic disorder, having a first-degree relative (parent, sibling, or child) who meets the criteria for hEDS is a strong clinical indicator ^[12]. However, a lack of known family history does not rule out hEDS, as older generations may have simply gone undiagnosed or been misdiagnosed themselves.

Why the Correct Diagnosis Matters

Getting the right diagnosis changes the focus of your medical care. While physical therapy is crucial for both conditions, the approach is fundamentally different. Physical therapy for fibromyalgia typically emphasizes aerobic exercise, stretching, and pain modulation ^[16][17].

Conversely, physical therapy for hEDS must focus on stabilizing joints, improving proprioception (body awareness), and safely strengthening the muscles around loose joints to prevent dislocations ^[11][16]. Traditional static stretching, often recommended for fibromyalgia, can actually be counterproductive or harmful for hEDS patients, as it further destabilizes already loose joints. Understanding whether your pain is driven by a central nervous system issue, mechanical joint instability, or a combination of both is the first step toward effective management. You can review the 2017 international hEDS diagnostic checklist available online to prepare for your medical appointments.