Can Cannabis Help Treat Shingles Pain?
Apr 26, 2020
Research on using cannabis for shingles is very limited, but some patients report positive effects from using it for neuropathic pain. This makes sense, since research shows that cannabis can be particularly helpful for treating this type of pain. The endocannabinoid system — with which cannabis interacts — is tasked with regulating pain signaling, so using cannabis may reduce the pain signaling involved in shingles-related neuralgia. While more research is needed, the evidence we do have suggests cannabis as a safe and effective treatment for this pain.
Research on shingles and cannabis
Research on cannabis for shingles has been extremely limited, but there is a long history of using cannabis to manage the condition. You can even find shingles listed as a use for cannabis as far back as 1851 in the United States Pharmacopoeia. These days, cannabis is used by some shingles patients on their own as a way to manage the painful neuralgia that is characteristic of the disease. But we still don’t have the kind of rigorous studies looking at shingles and cannabis that we’d need to make firm determinations about whether this use is effective.
Still, what we do have suggests that cannabis could be helpful.
- One small study on only eight participants looked at whether stimulating cannabinoid receptors could help reduce pain from facial neuralgia in shingles patients. They used a topical application — putting cannabinoid agonists directly on the face of the patients. The therapy brought on no adverse side effects for the patients involved, but did reduce pain for five of the eight patients in the study (62.5%), with an average reduction in pain of 87.8%. These results suggest that cannabis could ease pain for some shingles patients. Still, the low number of patients and lack of placebo controls limits the quality of this evidence.
That is the only study looking at cannabinoids and shingles specifically. Still, we can look at the research on using cannabis for pain, and neuropathic pain in particular.
- Pain is actually an extremely common reason that patients use cannabis. Surveys asking cannabis patients why they use cannabis have found that high percentages of patients report pain as their main reason for using cannabis. Some studies show positive results as high as 97% — and patients seem to be happy with the results. In a survey conducted by UC Berkeley, 81% of patients reported that cannabis alone was more effective at relieving their pain than opioids.
Of course, survey data is notoriously vulnerable to bias, so it’s also important to look into the clinical research on using cannabis for pain.
- For example, in 2017, the National Academies of Science and Engineering conducted a review on previous cannabis literature. Researchers reported that there is substantial evidence that cannabis is an effective treatment for chronic pain in adults, and tends to produce a moderate level of relief. Most of the research they reviewed was relevant to neuropathic pain specifically, so this is good news for shingles sufferers.
- Another 2017 review from Harvard University found “modest” evidence from clinical trials supporting the use of cannabis for pain, and even found evidence that cannabis use could help reduce opioid use when the two are used together.
- A 2018 review of using cannabis specifically for neuropathic pain also found evidence that cannabis could be effective. The authors explain that using low-dose cannabis, particularly when used sublingually or vaporized, can be a safe and effective option for neuropathic pain. But they point out that more rigorous research should be done to find out the best ways to utilize the many different forms of cannabis.
CBD and shingles
There is also research suggesting that CBD, a non-intoxicating cannabinoid in cannabis, can also offer pain-relieving benefits. This is partly because CBD is able to interact with our serotonin receptors to signal to the brain to reduce pain sensations. The World Health Organization recently did a full review on the medical literature on CBD and found that there is evidence to support the claim that CBD helps with pain. In fact, the WHO found that it was especially helpful for neuropathic pain — so it could be a helpful treatment for shingles.
It has also been found to be effective for pain when used in a topical formulation, which could be helpful for those who want to target a particular painful area — such as the face to combat facial neuralgia.
In addition, combining CBD with THC can have benefits. Studies show that the combination of these two cannabinoids can be more effective for pain relief than either one alone.
How cannabis works on shingles
The endocannabinoid system (ECS) exists in all vertebrates and helps regulate crucial functions such as sleep, pain, and appetite. The human body produces its own cannabinoids, which modulate and activate its various functions, but as its name suggests, the endocannabinoid system can also be modulated and activated by cannabinoids found in the cannabis plant. Because the entire system was only discovered in the past 30 years, scientists still have much to learn about the myriad ways cannabis affects the human body.
When it comes to shingles, there hasn’t been much research on how the ECS factors into the disease, specifically. But we do know that it is intimately involved in one particular symptom of shingles — neuropathic pain, or neuralgia.
This nerve pain relates to the endocannabinoid system because cannabinoid receptors CB1 and CB2 (which are activated by our natural cannabinoids and those in cannabis) are present in the nerves that are malfunctioning and causing pain in shingles. This means that stimulating these receptors could make an impact on the neuropathic pain.
In fact, one of the main roles of the endocannabinoid system is regulating pain sensation. When it is functioning normally, our natural cannabinoids activate CB1 when needed to reduce pain signals and our perception of pain. Stimulating CB1 receptors can even reduce our emotional response to pain by down-regulating the emotional pain response that comes up with physical pain.
Stimulating CB2 receptors can also reduce pain signaling. While scientists originally thought CB2 receptors were only found on immune cells, new evidence suggests that they are also present on nerve fibers and sensory neurons. Scientists now theorize that activating CB2 could mediate pain signaling through indirect activation of the opiate receptors — which can also reduce pain.
So while it’s unclear whether the ECS is involved in the progression of shingles, it is clear that it is involved in the severity of the neuropathic pain related to shingles. This has led some researchers to suggest that targeting the endocannabinoid system could be an effective way to reduce this painful neuropathy.
Despite the positive potential for cannabis and shingles, there are some potential side effects to be aware of. Cannabis can cause a wide array of side effects such as respiratory discomfort like coughing and increased phlegm (when inhaled), temporary cognitive deficits, short-term memory loss, a racing heart, and impaired coordination.
It can also include bigger risk factors for some — such as increasing risk of psychosis for schizophrenic patients, or increasing the risk of certain cardiac conditions. For a minority of patients, it can lead to addiction.
In studies on cannabis and neuropathic pain, common negative side effects were sleepiness, dizziness, and mental confusion.
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Shingles appears as a painful rash that is caused by the varicella-zoster virus, the same virus that causes chickenpox. After you’ve contracted and recovered from chickenpox, the virus remains dormant in the central nervous system, in the nerve tissue close to the spinal cord and the brain. It can reactivate and cause shingles at any time, often decades later.
You can get shingles anywhere on your body, including on your face, eyes and genitals, but it’s most common for it to appear as a strip of blisters around the left or right-hand side of your torso. Shingles is rarely life-threatening, but it can be very painful.
Shingles is a common condition that affects almost one out of every three Americans at some point in their life, and incidence is rising. The risk of getting shingles increases as you get older, and jumps dramatically over the age of 50. Most people only get shingles one time, but for some people it can recur, especially when their immune system is under duress due to another condition. There are vaccines that can lower your risk of getting shingles, and early treatment shortens the time it takes to recover and reduces the chance of complications.
The main symptom of varicella zoster is a rash that follows a specific nerve along the skin.
Before the rash appears, many people experience symptoms that include:
- Malaise (general feeling of discomfort)
- Tingling in a specific area of the body under the skin.
- Upset stomach
- Intense, shooting pain in one specific area of the body
After the initial phase, which often consists of the symptoms above, a rash begins to appear. It can appear anywhere but most often appears on the torso, but can appear anywhere on the body or head.
- At first it appears as hives or red blotches on the skin. This usually appears in a line which is where a specific nerve innervates the skin which is called a dermatome. It is usually a line, stripe or belt type of pattern over the skin and is characteristic of the disease.
- The rash then becomes vesicular, or forms small blisters which may leak some fluid called exudate. These vesicles can be very painful to the touch and burning. They can also fill with blood.
- The blisters begin to dry and crust, eventually falling off and the skin heals.
Occasionally discoloration and scarring can form where the rash was.
Although shingles itself is rarely life threatening it can have serious complications, especially if you are over 60 years old. Approximately 1-4% of people who get shingles will need to be hospitalized because of complications. Complications can include:
- Difficulty moving your face.
- If the rash is near your eye, it can interfere with your vision. If left untreated, it can cause permanent eye damage.
- Postherpetic neuralgia (PHN), or ongoing, severe pain in the area of the rash that lasts long after the rash has cleared up. It’s the most common complication, affecting 10-18% of people who get shingles.
- It can lead to chronic and even life-long severe pain in the area of distribution where the rash was.
- If shingles isn’t treated properly, the blisters become infected, leading to more complications.
- The central nervous system can be affected, leading to seizure, encephalitis, hemorrhage, and rarely death.
When you have shingles, it is very contagious, and you can infect people around you with the varicella-zoster virus, which can cause serious complications for pregnant women and anyone with a weakened immune system.
Shingles is usually diagnosed based on the distinctive pattern of the rash. Your doctor may also take a culture from the blisters to be examined in the laboratory.
Shingles is caused by the varicella-zoster “chickenpox” virus, which remains dormant within your body after you’ve recovered from chickenpox. You can’t catch shingles from being around someone who has shingles or chickenpox. It’s not clear what reawakens the virus, but some risk factors include:
- Being aged over 50
- Receiving chemotherapy or radiation treatment
- Getting cancer, HIV, or some other condition which reduces your immune system
- Experiencing a serious physical injury
- Taking long-term steroids or other medications that can weaken your immune system
Many people have no idea what triggered their shingles attack.
There’s no cure for shingles; you just have to wait for it to get better on its own. However, you can take prescription antivirals to speed up recovery and reduce the risk of complications. The main medications are:
- Acyclovir (Zovirax)
- Valacyclovir (Valtrex)
These work best if you start taking them within three days of the onset of symptoms.
Shingles can be very painful, so your doctor might also give you pain relief medication, including:
- Analgesics like Tylenol (Acetaminophen, Paracetamol) or NSAIDs (Ibuprofen, Naproxen)
- Topical pain relief creams like lidocaine and capsaicin (Qutenza)
- Anticonvulsants like gabapentin (Neurontin)
- Narcotics such as codeine
- Tricyclic antidepressants like amitriptyline
You can also try taking a cool bath to reduce the pain, and applying cool, wet compresses.
Vaccines against shingles
The chickenpox vaccine (Varivax) is now a routine childhood vaccination to prevent chickenpox. It can also reduce the risk of developing shingles, and lower the risks of complications if you do get it.
There are now two vaccines that can help prevent shingles:
- Zostavax is a live vaccine that protects against chickenpox for around five years. It’s only recommended for people aged 60 and over.
- Shingrix is a newer, non-live vaccine given in two doses, 2-6 months apart. It’s recommended for people aged 50 and over.
The vaccines help prevent shingles, reduce the severity and length of time that the disease lasts if you do catch it, and lowers your risk of developing PHN and other complications.