Polymyalgia rheumatica and fibromyalgia both cause muscular pain and stiffness in the joints. But they also have distinct symptoms and distinguishing characteristics.
The treatments for polymyalgia rheumatica and fibromyalgia differ significantly as well. A proper diagnosis is vital so treatment can begin, and you can regain quality of life.
Read on to learn the differences between Polymyalgia Rheumatica and Fibromyalgia: descriptions, symptoms, diagnosis, and treatments.
What Is Polymyalgia Rheumatica?
Polymyalgia rheumatica (PMR) is an inflammatory rheumatic disease that leads to muscle aches and stiffness throughout the body.  The most common symptoms are joint pain and morning stiffness, particularly in the neck, shoulders, and pelvis. 
Polymyalgia means a disease caused by inflammation that leads to muscle aches and stiffness throughout the body. Rheumatic diseases, which include inflammatory or immune-mediated conditions, that affect your joints or muscles are often referred to as “arthritis.” So, polymyalgia rheumatica is an inflammatory disease that affects the muscles and joints, possibly caused by an immune-mediated response.
Symptoms of Polymyalgia Rheumatica
The most common symptoms of PMR are pain and stiffness on both sides of the body, especially in the neck, shoulders, upper arms, back, hips, and thighs. Most people with PMR have difficulty turning in bed, getting out of bed in the morning, or moving after a long period of inactivity. It may affect other morning activities, such as bathing, dressing, or brushing your hair. Symptoms usually ease and go away as the day progresses.
Non-pain symptoms may also be present with PMR and may include:
- Weight loss
- Joint swelling
- Loss of appetite
- Low-grade fever
- Reduced movement in the neck and hips
- Widespread tenderness over the shoulders, neck, arms, and thighs
- Decreased movement in the shoulders without weakness or muscle shrinking
Most people who develop PMR are over the age of 50. Symptoms typically develop relatively quickly, within a day or two to a few weeks. 
PMR is considered a form of arthritis but does not typically cause progressive joint erosions like those seen in rheumatoid arthritis. 
Since PMR symptoms can overlap with several other medical conditions and no specific blood or imaging tests can definitively diagnose it, it may take a while to get a diagnosis of PMR. So how do you start that process?
Doctors diagnose PMR based on symptoms, the timing of the symptoms, and a physical examination. Your doctor may recommend imaging or blood tests to look for inflammation in your body or rule out other conditions that can cause the same or similar symptoms.
These may include:
- CT scan
- PET scan
- Blood tests, such as erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), or white blood cell count (WBC)
Your doctor may also use these tests to check for severe blood vessel problems sometimes associated with PMR. If your doctor suspects PMR, they may start you on oral steroids to decrease the inflammation in your joints. If your symptoms begin to clear up, the treatment itself can confirm a PMR diagnosis.  
Prevalence of Polymyalgia Rheumatica
Polymyalgia rheumatica is the most common inflammatory rheumatic disease in people over 50. It is rare in people under 50 years old, and affects women 2-3 times more often than men.
PMR primarily affects white people; the highest incidence occurs in people of northern European descent and Scandinavian countries. 
What Is Fibromyalgia?
Fibromyalgia is a complex pain regulation disorder characterized by chronic, widespread musculoskeletal pain. Fibromyalgia, also called fibro, is often classified as a central sensitization syndrome.
In a central sensitization syndrome, your central nervous system (brain and spinal cord) become hyper-sensitive to nerve impulses. As a result, you may experience pain differently or more intensely than other people do. For example, you may feel tingling or burning when a hair brushes against your face.  
Symptoms of Fibromyalgia
- Widespread pain
- Cognitive difficulties, known as “brain fog” or “fibro fog”
- Anxiety or depression
- Abdominal symptoms, like irritable bowel syndrome (IBS)
Unlike PMR, where symptoms improve over the course of the day, fibromyalgia symptoms may wax and wane throughout the day. They also may change from day to day or over time.
You may also have “fibro flares.” Flares are periods when your symptoms are worse than usual or when different symptoms appear. Fibro flares may occur for a few days or weeks, then symptoms will return to their baseline state.
Fibromyalgia is diagnosed based on criteria the American College of Rheumatology sets out. These criteria include two symptom self-assessment tests, the Widespread Pain Index (WPI) and the Symptom Severity Score (SSS).
- The WPI evaluates painful areas of the body.
- The SSS evaluates associated symptoms, such as fatigue and difficulty concentrating.
There are no definitive blood tests or image scans to diagnose fibromyalgia, but your doctor may recommend specific tests to rule out other conditions that may cause the same or similar symptoms.
Prevalence of Fibromyalgia
Fibromyalgia is more common in women than men. This may be the result of society’s views of men vs. women, and is some cases, a doctor’s bias. It usually develops between the ages of 20 and 55 but can be diagnosed at any age. Your risk of developing fibromyalgia increases if you have other rheumatic diseases. 
Differences Between Polymyalgia Rheumatica vs Fibromyalgia
Although polymyalgia rheumatica and fibromyalgia share some similarities, they are different disease processes caused by different factors, and your doctor will treat them differently.
Causes of Polymyalgia Rheumatica vs. Fibromyalgia
Polymyalgia rheumatica and fibromyalgia both have genetic factors and tend to run in families. Environmental factors, such as stress, play a role in both PMR and fibromyalgia as well. But that is where the similarities end.
PMR is an inflammatory condition, considered to be immune-mediated, in which the body’s immune system attacks healthy tissue. This tissue damage causes the inflammation, pain, and stiffness associated with PMR.
Fibromyalgia is not considered an inflammatory or autoimmune disorder; it is a nerve processing disorder that affects the central nervous system. Another difference is PMR develops relatively quickly; fibromyalgia tends to develop over time. Due to its quick development, doctors and scientists suspect PMR may begin due to some forms of cancer treatments, certain viral infections that reactivate after lying dormant in the bones for a long time, or excessive exposure to ultraviolet radiation from the sun. 
Doctors and researchers have yet to find a specific event that leads to the development of fibromyalgia. It may be triggered or aggravated by various physical or psychological stressors or emotional or physical trauma, including physical or mental trauma in either childhood or adulthood, although not everyone with fibromyalgia reports trauma.  
Symptoms of Polymyalgia Rheumatica vs. Fibromyalgia
Polymyalgia rheumatica and fibromyalgia have several symptoms in common, including: 
- Tender areas over the muscles
- Morning stiffness
- Muscular pain
But fibromyalgia has some distinct symptoms that do not usually occur in PMR, including: 
- Difficulty concentrating, or fibro fog
- Sleep difficulties and feeling unrefreshed after sleeping
- Headaches, including migraines and tension-type headaches
- Irritable Bowel Syndrome (IBS) symptoms, such as abdominal pain or diarrhea
- Tingling in the arms or legs, heart palpitations or dry eyes
Some symptoms may be similar, but the timing is different. Most of the time, PMR only affects people over 50, and the symptoms usually come on rapidly. Fibromyalgia symptoms typically start between 20 and 50, and the progression is generally slower.
Treatments for Polymyalgia Rheumatica vs. Fibromyalgia
Doctors use glucocorticoids, or steroids, to treat polymyalgia rheumatica. These steroids decrease your body’s autoimmune or inflammatory response, which reduces pain and stiffness. PMR generally responds quickly to steroids and will typically resolve within a few years. 
Since fibromyalgia is not an autoimmune or inflammatory disease, steroids are not typically prescribed. Your doctor will recommend treatments based on your needs, symptoms, and physical condition. Treatment methods are multi-modal, meaning your doctor will likely recommend a combination of lifestyle changes, physical or behavioral therapies, and medication.
Your doctor may recommend: 
- Mindful movement: Gentle movement can decrease pain and improve your sleep quality. Most doctors recommend at least 30 minutes of aerobic exercise 3 times a week. Gentle activities, such as water exercises or yoga, may be beneficial.
- Diet Changes: Your diet affects every aspect of your life. Your doctor may recommend a nutritionist or dietician, or they may recommend a particular diet, such as the Mediterranean diet, to reduce symptoms and improve your overall health.
- Medication: Your doctor may recommend over-the-counter pain medication, such as Tylenol or ibuprofen. Or they may prescribe antidepressants or anticonvulsants to control some symptoms.
- Other Treatments: You may benefit from physical therapy, massage therapy, or behavioral therapies, such as Cognitive Behavioral Therapy (CBT). Behavioral therapies may be available in person or online, such as through the self-guided Stanza app for fibromyalguia.
Seeing a Doctor for Polymyalgia Rheumatica vs. Fibromyalgia
Talk to your doctor if you have pain, stiffness, or other symptoms that interfere with your daily activities and quality of life. Although both PMR and fibromyalgia can be challenging to diagnose, there are still some things you can do to help the process run more smoothly.
Track Your Symptoms
Track your symptoms and their timing in a notebook. Some things that can be helpful to track:
- Did the symptoms develop quickly, or was it slow?
- What time of day do you experience the most pain?
- Write down where the pain is and what time of day it occurs.
- Write down any other symptoms you experience.
- Write down what helps the symptoms or makes them worse.
Take a Fibromyalgia Self-Test
Take an online fibromyalgia assessment if you suspect you have fibromyalgia. Bring your test results and symptoms notebook with you when you visit your doctor. This assessment, for example, uses the same scoring protocols as the ACR guidelines.
Polymyalgia rheumatica and fibromyalgia have similar symptoms, but their timing, causes, and treatments differ.
Talk to your doctor if you have widespread pain and stiffness and suspect you may have PMR or fibromyalgia. Consider taking the fibromyalgia self-tests before your appointment and have the results ready for your doctor.
Getting a proper diagnosis can take time and effort. But, together, you and your doctor can make a diagnosis and begin a treatment plan to help you live life to the fullest.
- Acharya S, Musa R. Polymyalgia rheumatica. In: StatPearls. StatPearls Publishing; 2023.
- Lundberg IE, Sharma A, Turesson C, Mohammad AJ. An update on polymyalgia rheumatica. J Intern Med. 2022;292(5):717-732.
- Bhargava J, Hurley JA. Fibromyalgia. In: StatPearls. StatPearls Publishing; 2023.
- What Is Known about the Causes of Fibromyalgia? Institute for Quality and Efficiency in Health Care (IQWiG); 2018.