What Is Referred Pain?

Everyone has experienced pain at some point in their lives: that sensation telling you to stop what you are doing to protect your body. Pain can be experienced in many different ways, from a slight prickling sensation at pricking your finger on a pin to the excruciating pain of a broken bone or a migraine. But do you know why a heart attack causes pain in the left arm or jaw or why eating something cold causes a “brain freeze”? To find out all about referred pain, including its causes, diagnosis, and treatment, continue reading below. 

What is referred pain?

Pain is a complex and multifaceted sensation that can originate from various sources within the body. One intriguing aspect of pain is referred to as pain, a phenomenon in which pain is felt in a different location to the actual source of the problem. This can often be misleading, as you might not realise that another part of your body is injured. Understanding referred pain is essential to diagnose and treat any underlying conditions.

Causes of referred pain

Referred pain occurs because the nerves in your body are all connected, and some can converge onto the same pathways. When your body experiences a pain stimulus, the nervous system carries the signal to your brain, which then sends a signal to your body to avoid whatever caused the pain. However, sometimes, the nerves from different regions of the body converge onto the same pathways in the spinal cord before they reach the brain like wires getting crossed in a circuit. This can make the brain think that the pain signal is coming from a different location, causing the perception of pain in this distant area.¹

Referred pain is generally visceral pain, that is, pain originating from your internal organs, although it can also be classified less commonly as somatic pain (originating from other tissues, e.g. muscles) or neuropathic pain (originating from nerves).

The Convergent-Projection theory proposes that referred visceral pain is caused by the convergence of nerves originating from both the skin and internal organs. Normally, a lot of signals from the skin are sent to the brain to reflect the many external stimuli coming into contact with your skin, whereas your internal organs do not send as many signals. Therefore, if your organs are injured and generating an unusually high amount of signals, the brain assumes this pain signal is coming from the skin and pain is experienced there instead.^2,3

Some of the most common examples of referred pain include:

• Heart attack: A heart attack or other cardiac problems often causes pain in the chest area around the heart. However, pain is also often felt radiating out of the chest and into your left arm, back, neck, or even your jaw.
• Kehr’s sign: Upper back pain, particularly between your shoulder blades, is considered a classic symptom of a ruptured spleen.
• Lung cancer: Issues with the lungs or diaphragm can cause referred pain in the upper shoulder area or one side of the neck. Shoulder pain is particularly common in lung cancer; for example, 96% of patients with Pancoast lung tumours reported shoulder pain as one of their first symptoms⁴
• Pancreatitis: Problems with the stomach or pancreas can cause referred pain in specific regions of the stomach and back, with the majority of acute pancreatitis patients experiencing severe and constant abdominal pain that can radiate over the back.⁵
• Trigeminal neuralgia: Compression or damage of the trigeminal nerve (the fifth cranial nerve) can cause severe shooting pain in your lower face, including the jaw, teeth, and gums. Normally, only one side of your face is affected.  
• Brain freeze (sphenopalatine ganglioneuralgia): The feeling you get after drinking or eating something cold (for example, ice cream or slushie) is caused by extreme cold in your mouth and throat, but is experienced as a kind of referred pain in your brain and back of the head⁶

Diagnosis of referred pain

Distinguishing referred pain from local pain is crucial. If the wrong diagnosis is made this can lead to incorrect treatment being given, which could potentially worsen the underlying condition and even cause unnecessary surgical procedures. To diagnose referred pain, healthcare providers might use several methods:

• Medical history: A thorough medical history helps to identify potential sources of referred pain and any underlying conditions that may be contributing to it 
• Physical examination: A comprehensive physical examination is essential to locate the origin of referred pain. A healthcare provider might look for tenderness, muscle tightness, and signs of nerve irritation.
• Diagnostic imaging and tests: Imaging tests like X-rays, MRI, or CT scans can be used to confirm the source of your referred pain and any underlying conditions 

Treatment and management of referred pain

Treatment should target the underlying issue of referred pain, whether it is visceral, somatic, or neuropathic. If you treat the localised pain instead of the actual injured area, the pain will persist as the underlying condition causing the pain will remain untreated.

Treatment, therefore, depends on the underlying health condition; medication, physical therapy, or even surgical intervention might be necessary. For example, jaw pain caused by a heart attack requires urgent medical attention and possibly surgery, while jaw pain resulting from trigeminal neuralgia might require specific medications.

Pain management

Managing pain is a critical aspect of treatment. If you still experience pain after treating the underlying condition, or if the pain cannot be treated, your healthcare provider might recommend some treatments to help with pain relief:

• Medication (such analgesics or muscle relaxants)
• Physical therapy 
• Transcutaneous electrical nerve stimulation (TENS)
• Nerve blocks (either temporary or permanent)

Alternatively, at-home or holistic remedies could be used:

• Acupuncture
• Epsom salt baths
• Heat and ice treatment

It is important to note that, although some conditions cannot be fully treated, the pain should be managed. If you are living with uncontrolled pain, consult with your healthcare provider to start a care plan.  

FAQs

How can I tell if the pain I am experiencing is referred pain?

It can often be very difficult to tell whether your pain is referred pain because it can feel very similar to local pain. You might be able to tell if the pain is referred from an underlying medical condition or if you develop pain in an area that you know you haven’t directly injured. For example, it might be normal to develop shoulder pain after doing exercise or something, which could result in a pulled muscle, however, it might be a concern if you suddenly develop shoulder pain for no apparent reason. 

A healthcare provider can often diagnose referred pain based on a patient’s known medical conditions or medical history, the specific pattern of pain and how it presents, and by assessing any associated symptoms that can point to an underlying health condition. 

What does referred pain feel like? 

Referred pain can vary in its sensation and intensity depending on the underlying condition or source of pain.⁷ It can present as dull and aching sensations, or it can be a sharp and stabbing pain. The pain might be constant, or it might come and go with varying intensity. This variation contributes to the difficulty in diagnosing referred pain - there is no set definition for how it should feel. 

How can I prevent referred pain?

Referred pain is often a symptom of an underlying condition, therefore the pain can be prevented by preventing or reducing the risk of developing these conditions in the first place. For example, you can reduce the risk of having a heart attack by reducing consumption of high-fat foods, stopping smoking, and reducing blood pressure. 

While there is little you can do to specifically prevent referred pain, the general advice is to maintain a healthy lifestyle: exercise regularly, eat a balanced diet, manage stress, and keep up with regular check-ups. 

Will the referred pain go away?

Whether referred pain goes away or not depends on the underlying cause of the pain. In many cases, referred pain will resolve as the underlying condition is treated or as your body heals. For example, if your referred pain is caused by a muscle strain or injury, it may improve with rest, physical therapy, or other appropriate treatments, and the pain should eventually subside.

However, if the source of the referred pain is a chronic medical condition (a condition that is persistent or has long-lasting effects), such as trigeminal neuralgia, chronic pancreatitis, or arthritis, the pain may be recurring or persistent. In these cases, your referred pain may not completely go away, but it can be managed with proper medical care and treatment.

Summary

Referred pain is a fascinating yet potentially misleading aspect of how our bodies interpret pain. For anyone experiencing discomfort or pain that seems to radiate or appear in unexpected places, understanding referred pain can be critical. By learning about the underlying causes, characteristics, and diagnostic methods of referred pain, you can be more informed to communicate with healthcare professionals about your symptoms. This can lead to more accurate diagnoses and effective treatments, ultimately improving your well-being and quality of life. So, if you ever find yourself puzzled by pain that doesn't quite add up, consider that referred pain might be the key to understanding and addressing it.