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Do you find yourself constantly wanting to scratch? You may not realize there is a link between your kidney disease and itchy skin. If your kidneys are not functioning properly you may be suffering from uraemic pruritus. This itching in kidney disease is common for many people with chronic kidney disease. Read on to learn about kidney disease-associated pruritus, why it occurs, and how to combat itching.
What Is Itching In Kidney Disease?
Uraemic pruritus or uremic pruritus (UP) is a fancy way of saying itching in kidney disease. This condition occurs in those who have chronic kidney disease (CKD). There is incessant pruritus, or itch that occurs all over the body.
CKD-associated pruritus often occurs during end-stage renal disease (ESRD). Also referred to as renal failure is the final stage of CKD when kidney function has declined to the point that the kidneys can no longer function on their own.
Those with ESRD will need dialysis treatment since the kidneys are no longer able to filter the blood.
How Common is Itching In Kidney Disease?
Itching in kidney disease is most common in those on dialysis. Between 20 and 50 percent of hemodialysis patients (or haemodialysis patients) will experience pruritus in CKD. This is an improvement from the early days of dialysis. Back then kidney failure itching would affect 100 percent of those undergoing dialysis.
A study in the Acad Dermatol Venereol journal found that itching after dialysis is also more common among men than women.
There are also cases in people who are not on dialysis. Itching is typically a kidney failure symptom, but stage 3 kidney disease and itching have also been seen. So even if you are not on dialysis, the renal itch is an important symptom to look out for. It can tell if your CKD is progressing.
What Causes Itching in Kidney Disease?
The kidney disease-itchy skin connection has been researched. However, the Itchy skin kidney problem is still not well understood. There are various theories as to why itching in kidney disease occurs. They include the following reasons:
- Excess uremia
- Elevated phosphorus
- Inflammation, histamine, and allergic reactions
- Dehydration and dry skin
- Other existing health conditions
- Not enough dialysis
- Neurological changes
Damaged kidneys cannot process urea properly. As a result, this compound will build up in the body, called uremia. Large amounts of uremia become toxic. Uremia can affect calcium and phosphorus levels as well. This compound also can activate itch fibers.
Elevations of Calcium and Phosphorus Levels
The intensity of the itch may have to do with calcium and phosphate levels being out of whack. Some research shows that calcium and phosphorus levels will build up more in people with pruritus. Phosphorus intake from foods can also increase itching.
Uremia Can Affect Parathyroid Hormone Function
Dysfunction in kidneys can result in altered parathyroid hormone (PTH) function. Kidney dysfunction may elevate PTH levels and cause itching.
Inflammation, Histamine, and Allergic reactions
There is some evidence that chronic inflammation causes itching in kidney disease. Those with UP also had elevated inflammatory markers. These included C-reactive protein, T helper (Th)-1 cells, and interleukin-6.
With inflammation comes a response from the immune system. The skin will release hormones telling the brain to activate itch receptors on the skin. This produces itching cells, called pruritogenic cytokines. These cells tell your immune system that something is wrong. Your skin will then create immune cells that will activate an itch receptor in the skin making you feel itchy.
Histamine is also released as a defense mechanism of the skin when inflammation occurs. Histamine levels often tend to be higher in those with uremic. However, higher histamine levels do not lead to a more severe itch. It just means that where there is histamine there may be an itch.
One theory is that nerves in the skin have histamine receptors. This means that if the receptor can be shut off then so can the itch. This theory tested positive in animal studies. Stopping the receptors also stopped the itch.
Inflammation in CKD occurs when the disease goes unmanaged. Dialysis itself can also lead to inflammation. This arises from the use of non-biocompatible dialyzers, poor sterilization, and infections at the site of injections. The more active the immune system the more likely you are to itch. Inflammation may also arise from allergies and sensitivities to foods and products that are put on the skin.
Dehydration and Dry Skin
People with ESRD often have dry skin, but the connection between dry skin and itching is not so clear. What has been determined is that dry skin makes the itching worse and more severe.
Getting less fluid can cause itchy skin to get worse. Hydration is important for kidney health especially if you are on dialysis. The fluid removed during dialysis needs to be replenished. So getting enough hydration between treatments could help lessen the intensity of the itch.
Dry skin becomes dangerous when it turns into nephrogenic systemic fibrosis (NSF). This condition results in the hardening of the skin causing it to become thick and tight. It also can scar the lungs and kidneys. Too much gadolinium causes this condition. Kidney patients are exposed to this during imaging and dialysis expose kidney patients to this compound. NSF is also responsible for kidney itch.
Some people with kidney disease also have nerve damage that prevents them from sweating enough. This could lead to dry skin and is another reason to keep hydrated.
Other Existing Conditions
Renal itching is more likely to occur in those with additional health conditions. Those with diabetes, hepatitis, and iron deficiency anemia often complained of itching.
Diabetics were more likely to have pruritus than nondiabetics with kidney disease. Blood sugar levels can affect itching. Diabetics on hemodialysis with higher blood HbA1c levels had a higher itch score than nondiabetics.
Those with kidney disease may not make enough red blood cells and are at risk for iron-deficiency anemia. This condition was found to increase itchiness. Viral hepatitis may also be a cause of renal itching.
Opioid receptors in the central nervous system can reduce pain. Less receptor activity was found in the skin of CKD-associated pruritus people on dialysis. This lower receptor activity also intensified the itch in these patients.
Changes in receptors can affect nerve endings in the skin that sense stimuli. Nerve cells known as C neurons or C-fibers are responsible for why we feel an itch. There are free nerve endings on these cells. These nerve endings send messages to the brain telling it something is stimulating the nerve ending. These messages will tell the skin to feel different sensations such as hot, cold, pain, and itch.
C neurons are also responsible for producing a histamine-related itch. The itch can also occur because of other nerve cells not related to histamine. These non-histaminergic neurons are unresponsive to antihistamine products.
Nerve Problems Due to Uremic Toxicity
This damage may increase the perception of itch no matter the size of the rash. People on hemodialysis with a neurotransmitter-induced skin rash had a higher sense of itch even when they had a smaller skin flare.
Not Enough Dialysis
Dialysis itself can lead to itchy skin. Whether you’re getting too little or too much, the amount of dialysis can affect your skin. If you’re feeling itchy it may be time to talk to your healthcare provider to see what changes can be made.
How Will Itching In Kidney Disease Affect Your Skin
Pruritus affects everyone differently. It can range from mild to severe. Itching can be in one little place or it can ravage your entire body. Itching commonly occurs on the back, abdomen, head, and forearms.
Other Ways Itching in Kidney Disease Can Affect Your Skin
Itching is not the only thing that can occur in kidney disease. Other dermatological conditions include the following:
- Scratching and scratch marks
- Thick, callous skin
- Bumps and lumps
- Color changes
- Nail changes
- Tight skin
- Calcium deposits
- Perforations of the skin
Scratching and Scratch Marks
Too much scratching can also develop into secondary skin conditions. It can rub off the top layer of skin. Impetigo can also occur as a result of scratching. This is a skin infection caused by bacteria, specifically Streptococcus and Staphylococcus aureus.
Thick, Callous Skin
Lichenification is skin that has become thick and leathery due to constant scratching or rubbing.
Lumps and Bumps on the Skin
Kidney itching can cause hard, itchy bumps known as prurigo nodularis. They also appear as prurigo lesions. Try not to scratch these. They can cause more skin lesions to appear.
Color Changes to your Skin
During ESRD the skin will change color. It can become a pallor or yellow hue. The yellow color is related to anemia and hormone imbalances. Pallor is a slate-grey discoloration. It occurs when iron is trapped in skin cells.
Kidney disease can result in small, narrow, and thickened fingernails. Nails can also discolor and split in half.
In CKD the kidneys are not able to properly filter and remove toxins. This can lead to the buildup of fluid in the body. It will often result in swelling in the legs, hands, face, feet, and/or ankles.
Rashes are common in kidney disease. They can occur for different reasons and often are the result of taking multiple medications.
Blisters are common in ESRD. They can occur on the foot and in other places. Blisters are often itchy and also painful.
Tight skin is the result of too much gadolinium. If the condition persists it can also cause kidney and lung cells to harden.
Calcium Deposits Beneath Skin
The calcium imbalance from excess uremia can cause a condition called calciphylaxis. If the condition persists it can also cause kidney and lung cells to harden. It can cause blood clots, painful skin ulcers, and infections that may lead to death.
Perforation of the Skin
Available Treatments for Itching in Kidney Disease
You may be wondering how you can stop this horrible itching in kidney disease. Unfortunately, there is no one right answer. Uremic pruritus treatment varies from person to person and there are modalities used to treat this condition. They include:
- Improve dialysis
- Reduce inflammation
- Topical Treatments
- Physical Therapies
- Newer Treatments
Improving the effectiveness of dialysis may help stop the itch. Optimizing dialysis eliminates urea which seems to be a big factor in the cause of itchy skin. Ways dialysis can be improved is by the following:
Aside from better filters just optimizing the schedule of dialysis may help lessen the itching. If you are currently under dialysis and suffering be sure to ask if you need to revise your treatment schedule.
Allergic reactions and sensitivities can increase Inflammation which will make itching worse. The dyes and fragrances in products can set off an itching fit. So one way to reduce inflammation is to be aware of any issues you have with soaps, laundry detergents, lotions, perfumes, and anything else that comes into contact with your skin.
Hot water and heat can make your skin dry and cause it to be itchy. Be sure your showers and baths are not too hot.
Seeing a dermatologist may help with any underlying skin conditions. They can provide topical treatments that might be helpful. Moisturizer and gentle skincare products can also lessen the itch.
Menthol or pramoxine are two ingredients found to be helpful. The topical capsaicin works when itching is specific to one area of the body. Capsaicin desensitizes nerve endings. This will block pain and itch. The only downside is that it causes a burning sensation which may make you not want to use it for very long.
One study showed it reduced itching by 80% in those with ESRD pruritus. Other research said there was little difference between and the itch. Participants experienced the placebo effect in this study. The treatment group and those who received a placebo had a greater than 70% reduction in itch severity. This had to do with the feeling of moisturized skin along with better care from physicians.
So it’s hard to say what is happening with this tropical treatment. There is also a possibility it could cause skin cancer. It should be a last resort. Don’t use this product for more than five weeks.
Skin emollients containing 80% water significantly reduced the itching. Using 2.2% gamma-linolenic acid cream three times a day for 2 weeks worked better than the placebo and successfully reduced itching.
Essential oils also improved skin hydration which can help with reducing symptoms of this condition.
If the itching is widespread topical you may want to try a medication so you’re not stuck rubbing expensive ointment all over your body.
Medicines for Itching In Kidney Disease
Many medications for pruritus have been found to have conflicting results. Typical treatments for UP include gabapentin, pregabalin, and antihistamines.
One medicine that successfully lowers itch is gabapentin. This medication helped those with renal disease ranging from stage 3 CKD to ESRD. A dose of 100 mg was given to renal patients; both those who were not undergoing dialysis.
Caution should be used when taking gabapentin. It has side effects that include drowsiness, dizziness, fatigue, blurred vision, unsteadiness, and confusion. Surprisingly, those on dialysis had a lower rate of side effects.
Pregabalin can be a substitute for gabapentin. Small studies show that taking doses of 25 to 75 mg at nighttime is effective for hemodialysis patients who cannot tolerate gabapentin.
Antihistamines have little or no effect on pruritus even though they are still being prescribed today.
H-1 receptor antagonists have sedative effects but no specific effects on itching itself. Newer research shows it was doing basically what the placebo did.
Physical Therapies for Itching in Kidney Disease
There are therapies that can be done to the skin itself. These physical therapies include phototherapy and acupuncture.
Phototherapy for Itching in Kidney Disease
Ultraviolet B (UVB) phototherapy works by stopping the spread of the substances that cause the itch. This therapy also stops inflammation from the immune response.
UVB phototherapy is effective for ESRD pruritus. Some therapies perform better than others.
Narrow band-UVB (NB-UVB) phototherapy and UVA alone do not appear to be as effective. Itching came back soon after 6 weeks of NB-UVB. To fully control itching, these therapies need to be done continuously over time. Initially, this type of phototherapy needs to be done three times per week. After that each week an additional one to two sessions needs to be done for maintenance.
Broadband (BB-UVB) phototherapy worked the best. Nine out of 10 patients had a marked improvement in itching after 6 BB-UVB treatments. These effects lasted for at least six months.
Acupuncture for Itching in Kidney Disease
Acupuncture is a common complementary therapy for many conditions involving pain. The theory for itch relief is that acupuncture will block itch impulses. Acupuncture generates impulses, similar to nerve messages. In response, an opioid-like substance will be released.
This substance will block the slower C fiber impulses and stop the itch. When compared with the placebo (a non-acupoint needle) acupuncture helped stop the itch.
The only problem with this therapy was there might be bias in the research. The good thing about acupuncture is there are no lasting side effects and could be a nice complementary treatment to patients. This can be an alternative for those who are having trouble with other treatments or don’t want to take medication.
Newer Therapies for Itching in Kidney Disease
Uremic pruritus could not just be an isolated skin condition and may have underlying neurological ramifications that need to be addressed. The most likely scenario is that there is an imbalance in the nervous system. The answer to the itch would be correcting these imbalances.
Opiates trigger itching so finding an opiate antagonist may be the solution to this itchy problem. When tested these medications had some success. The best medication for stopping itch was that consisting of both an agonist and antagonist.
The National Library of Medicine has indicated the following as new therapies to stop itching in kidney disease:
This opioid receptor antagonist is a pain reliever. It can inhibit histamine and other substances that trigger scratching in animal studies. In humans, Nalfurfine is well tolerated with rare side effects. However, it was not helpful to those with really bad itching.
Results had only a mild or no effect with only a third of people feeling that itching intensity slowed. There is still a lot we do not know about this medication.
This medicine is a part opiate agonist and partial opiate antagonist. It can significantly reduce itching among people on hemodialysis.
Difelikefalin (CR845) is an intravenous opiate agonist. This medication does not cross the blood-brain barrier and will not produce undesirable hallucinogenic side effects. Eight weeks of this medication resulted in 33 percent of patients feeling their itch improved very much when compared with just 9% in the placebo group.
This medication is an opioid receptor antagonist that showed conflicting results when it comes to kidney itching. It was only helpful in the most severe cases. Naltrexone also did not affect in reducing pruritus when compared with a placebo. The bad digestive side effects also make it not advisable to use.
Topical cannabinoids have been researched and also show some promising results. There is still a lot we do not know about this treatment.
Other New Medications
Other medications have been researched but less is known about these medications so they are not readily recommended. They include thalidomide, nicergoline, activated charcoal and neurotrophins, intravenous recombinant erythropoietin, intravenous lidocaine, and intravenous pentoxifylline.
If any of these medications are of interest be sure to talk to your doctor to know which is right for you to avoid unwanted side effects.
In addition to topical treatments, medications, and physical therapies, you can look to nutrition for an anti-itch treatment. Nutrition can help to combat inflammation and regulate mineral levels.
Control Inflammation with Nutrition
Nutrition helps lower inflammation that can occur in kidney disease. Foods that help kidney function are also foods that will lower inflammation. Fruits and vegetables should be added to the diet. These foods provide many antioxidants that can lower chronic inflammation associated with itching in kidney disease.
A high intake of animal protein is associated with inflammation. So including more plant proteins like soy (like veggie burgers, tofu, soybean), beans, and nuts in the diet can lessen the inflammation-related itch.
Remember if you’re on dialysis your protein needs need to be increased. Be sure to work with a renal dietitian who can help you determine your accurate protein needs.
Gut health also plays a role in the development of inflammation in CKD. Having a healthy microbiome may lower inflammation. Foods to improve kidney function can also increase healthy gut bacteria. Eating more fruits and vegetables will produce a healthier microbiome.
Those with secondary hyperparathyroidism and CKD may experience inflammation from milk and dairy products. If you have both of these conditions you may need to modify your dairy intake. As always it is best to speak with a renal dietitian for accurate nutrition information tailored to your needs.
Control Calcium and Phosphorus with Nutrition
Controlling your calcium and phosphorus levels is typically recommended for those with kidney disease. If you are suffering from pruritus you may need to pay closer attention to the foods you are eating.
Dialysis can control phosphorus levels but it is also important to know how much you are taking in between treatments. A normal phosphorus level is between 2.5 and 4.5 mg/dL. If your levels are higher than that you will need to limit such as meats, poultry, fish, nuts, beans, and dairy products. These foods are high in phosphorus.
Be on the lookout for phosphorus added to foods. If you see the word “PHOS” on a food label that means phosphorus has been added to it. Avoid these foods if you need to limit your intake.
If changing your diet hasn’t helped with the itching you can ask your healthcare team about taking phosphate binders. This medication can help to rid the body of excess phosphorus.
In those with UP calcium levels can be out of whack. A normal level is between 8.5 – 10.2 mg/dL. Having too much or too little calcium is dangerous. Some research indicates that regulating calcium levels can stop the itch.
This can be done by eating a well-balanced diet. Magnesium and vitamin D are two nutrients needed to absorb calcium. So whether your calcium levels are high or low will depend on how much magnesium and vitamin D you need.
A renal dietitian can help you find foods that will help to balance your calcium levels. They can also determine if you need to supplement vitamin D. Don’t start any supplements without speaking to your doctor or dietitian.
Correct Low Iron Levels and Iron-Deficiency Anemia
If you’re suffering from uremic pruritus you should check for iron deficiency. Your hemoglobin, transferrin saturation (TSAT) and ferritin levels can tell if you are low on iron. Physical symptoms can also be an indication you don’t have enough of this mineral. These include:
- Looking pale
- Being tired or weak
- Having”down” or depressed feeling
- Feeling short of breath with activity
- Having chest pain
- Feeling dizzy or light-headed
- Having numbness or coldness in your hands and feet
- Having a faster heartbeat
Treating the underlying iron deficiency may relieve the itch. The easiest way to get more iron is by increasing your intake of iron-rich foods. Foods high in iron include red meat, beans, and green vegetables. Some people may need to take a supplement or get iron injections to pump up their iron levels.
Before starting any supplements it is best to find a renal dietitian who can craft a nutrition plan that will best fit your needs.
Drink Enough Fluid
Hydration is another nutrition therapy that should be done if you are suffering from the itch. If you are on dialysis and feeling itchy you may need to up your water intake. Be sure to talk to your dietitian about your fluid needs. They will help craft a hydration plan that will help alleviate uremic pruritus.
Summary and Overall Protocol for Itching In Kidney Disease
There is increasing evidence that uremic pruritus is more than just an isolated skin condition. It could very well be an overarching disease that stems from nutritional, hormonal, and immune imbalances.The following protocol is recommended to correct these problems;
- Normalize parathyroid hormone
- Normalize calcium and phosphorus levels
- Optimize hemodialysis practices through treatment and filters
- Increase water
- Hydrate skin with skin emollients
- Try topical treatments
If no change is seen after two weeks with skin emollients, the next step is to speak with your doctor about trying a low dose (100 mg) of gabapentin after dialysis for two weeks. Titration may be needed depending on how it affects the UP.
If you are still having issues after taking gabapentin for two weeks, a 6-week broad band or a narrow band-UVB phototherapy session may further help.
If itching is still an issue after these additional therapies it could be an opioid receptor problem. In this case, using a mixed opioid receptor agonist-antagonists such as butorphanol may be something to consider.
Finding the source of the itch can be done with an integrated approach with multiple solutions appears to be the best solution for itching in kidney disease. If you are struggling with this condition be sure to sit down with your healthcare team to find what nutrition and medical treatments are right for you.