Pruritus is an itchy feeling that makes you want to scratch your skin. It may occur without a rash or skin lesions. Pruritus sometimes feels like pain because the signals for itching and pain travel along the same nerve pathways. Scratching may cause breaks in the skin, bleeding, and infection. If your skin feels itchy, let your doctor know so it can be treated and relieved.

The way pruritus feels and how long it lasts is not the same in everyone.

The skin is the largest organ of the body. The most important job of skin is to protect against heat, sunlight, injury, and infection. The skin is also important to self-image and your ability to touch and be touched.

What is itching?

Itching is an irritating sensation that makes you want to scratch your skin. Sometimes it can feel like pain, but it is different. Often, you feel itchy in one area in your body, but sometimes you may feel itching all over. Along with the itching, you may also have a rash or hives.

What causes itching?

Itching is a symptom of many health conditions. Some common causes are:

• Allergic reactions to food, insect bites, pollen, and medicines
• Skin conditions such as eczema, psoriasis, and dry skin
• Irritating chemicals, cosmetics, and other substances
• Parasites such as pinworms, scabies, head and body lice
• Pregnancy
• Liver, kidney, or thyroid diseases
• Certain cancers or cancer treatments
• Diseases that can affect the nervous system, such as diabetes and shingles

What are the treatments for itching?

Most itching is not serious. To feel better, you could try:

• Applying cold compresses
• Using moisturizing lotions
• Taking lukewarm or oatmeal baths
• Using over-the-counter hydrocortisone cream or antihistamines
• Avoiding scratching, wearing irritating fabrics, and exposure to high heat and humidity

Contact your health care provider if your itching is severe, does not go away after a few weeks, or does not have an apparent cause. You may need other treatments, such as medicines or light therapy. If you have an underlying disease that is causing the itching, treating that disease may help.

Certain conditions, cancers, and blood disorders may cause pruritus.

Pruritus is a symptom of a certain condition, blood disorder, or a disease. These include:

• Cancer and conditions related to cancer.
• Liver, kidney, or thyroid disorders.
• Diabetes mellitus.
• HIV or parasite infection.
• Dry skin.
• Drug reactions.
• Conditions related to stress, anxiety, or depression.

The cause of pruritus is not always known.

About 20 percent of pregnant women feel itchy during pregnancy. Usually women feel itchy in the abdomen. But red, itchy palms and soles of the feet are also common complaints. Pregnancy hormones and stretching skin are probably to blame for most of your discomfort. Usually the itchy feeling goes away after delivery.

What might help:

• Use gentle soaps and moisturizing creams.
• Avoid hot showers and baths.
• Avoid itchy fabrics.

Call your doctor if symptoms don't improve after a week of self-care.

Certain cancer treatments may cause pruritus.

Cancer treatments that may cause pruritus include chemotherapy, radiation therapy, and immunotherapy (biologic therapy).

• When chemotherapy causes pruritus, it may be a sign that you are sensitive to the drugs being used.
• Radiation therapy can kill skin cells and cause dryness, burning, and itching as the skin peels off.
• Drugs used in immunotherapy may also cause dryness and itching.

Skin can become thin and dry because many of these therapies make your skin less able to make new cells and heal. Long-term dry skin may occur when hair and sweat gland function does not return to normal right after cancer treatment.

Drugs may be used for supportive care.

Some of the drugs used to prevent or treat cancer symptoms may cause pruritus, including the following:

• Pain medicine such as opioids.
• Drugs for nausea and vomiting.
• Hormones such as estrogens, testosterone, or progestins.

Finding the cause of the itching is the first step in relieving pruritus.

Since pruritus is a symptom of a disease or condition, finding and treating the cause is the first step in bringing you relief.

A physical exam, blood tests, and a chest x-ray are done to assess pruritus.

The following tests and procedures may be done to find the problem that is causing the itching:

• Physical exam and history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. The doctor will check your skin for the following:
  • Signs of infection.
  • Signs of a drug reaction.
  • Redness, dryness, scratches, or lesions.
  • Abnormal color, texture, or temperature.

  A history of your health habits, past illnesses, and treatments will also be taken. You may be asked about the following:

  • When the pruritus started, how long it lasts, how bad it is, and what part of your body is itchy.
  • How it affects your daily activities and sleep.
  • What makes the itching better or worse.
  • Whether other family members or pets are affected.
  • Whether you have had pruritus before.
  • Current cancer treatment or past history of cancer.
  • Other diseases you have now or had in the past and their treatment.
  • Pain medicines, antibiotics, or other drugs you are taking, including illegal drugs.
  • Whether your diet is healthy and you drink enough fluids.
  • Social history (hobbies, job, sexual history, and travel).
  • How you care for your skin.
  • Your emotional health.
• Blood chemistry studies: A procedure in which a blood sample is checked to measure the amounts of certain substances released into the blood by organs and tissues in the body. An unusual (higher or lower than normal) amount of a substance can be a sign of disease. These blood tests include:
  • Kidney function tests.
  • Liver function tests.
  • Lactate dehydrogenase test.
  • Thyroid function tests.
• Complete blood count (CBC) with differential: A procedure in which a sample of blood is drawn and checked for the following:
  • The number of red blood cells and platelets.
  • The number and type of white blood cells.
  • The amount of hemoglobin (the protein that carries oxygen) in the red blood cells.
  • The portion of the blood sample made up of red blood cells.
• Sedimentation rate: A procedure in which a sample of blood is drawn and checked for the rate at which the red blood cells settle to the bottom of the test tube. The sedimentation rate is a measure of how much inflammation is in the body. A higher than normal sedimentation rate may be a sign of lymphoma or another condition. Also called erythrocyte sedimentation rate, sed rate, or ESR.
• Chest x-ray: An x-ray of the organs and bones inside the chest. An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body.

Depending on the results, further tests, such as a skin biopsy, may be done to diagnose the problem and decide on treatment.

Different types of treatment are used to help treat pruritus.

Self-care

Self-care includes avoiding pruritus triggers and taking good care of your skin.

Pruritus triggers include:

• Dehydration caused by fever, diarrhea, nausea and vomiting, or low fluid intake.
• Hot baths or bathing more than once a day, or for longer than 30 minutes.
• Bubble baths or soaps with detergents.
• Reusable scrubbing sponges for the face or loofahs for the body.
• Scents, fragrances, and perfumes.
• Adding oil at the beginning of the bath.
• Dry indoor air.
• Laundry detergent with scents, dyes, or preservatives.
• Fabric softener sheets.
• Tight clothes or clothes made of wool, synthetics, or other harsh/scratchy fabric.
• Underarm deodorants or antiperspirants.
• Skin care or cosmetics with scents, dyes, or preservatives.
• Emotional stress.

Ways to help lessen itching include:

• Using unscented, soothing creams or ointments.
• Bathing in slightly warm water no more than 30 minutes daily or every other day.
• Using mild skin cleansers (non-soap) or soaps made for sensitive skin (such as Cetaphil cleanser, Dove for Sensitive Skin, Oilatum, Basis).
• Adding oil and soap at the end of a bath or adding a colloidal oatmeal treatment early to the bath.
• Using soap only for dirty areas; otherwise water is good enough.
• Gently washing, if needed, with a clean, fresh, soft cotton washcloth.
• Rinsing all soap or other residue from bathing with fresh, slightly warm water.
• Drying off by patting skin instead of rubbing.
• Keeping home air cool and humid (including use of a humidifier).
• Washing sheets, clothes, and underwear in mild soap or baby soap that contains no scents, dyes, or preservatives (such as Dreft, All Free Clear, Tide Free and Gentle). Adding vinegar (one teaspoon per quart of water) to rinse water removes traces of detergent.
• Using liquid fabric softener that gets rinsed out in the wash (such as All Free Clear Fabric Softener) or avoiding fabric softener altogether.
• Using blankets that are soft, such as cotton flannel.
• Wearing loose-fitting clothes and clothes made of cotton or other soft fabrics.
• Using distraction, music therapy, relaxation, or positive imagery.

Over-the-counter treatments

Some over-the-counter treatments (medicines that can be bought without a prescription) help prevent or relieve pruritus. However, you should read labels carefully to look for ingredients that may trigger skin reactions, including alcohol, topical antibiotics, and topical anesthetics.

Cornstarch and talc

Cornstarch can help prevent itching of dry skin caused by radiation therapy but should not be used where skin is moist. When cornstarch becomes moist, fungus may grow. Avoid using it on areas close to mucous membranes, such as the vagina or rectum, in skin folds, and on areas that have hair or sweat glands.

Some powders and antiperspirants, such as those that contain talc and aluminum, cause skin irritation during radiation therapy and should be avoided when you're receiving radiation treatment.

For itching not related to radiation therapy, talc-based treatments may be better than cornstarch-based treatments, especially where two skin surfaces touch or rub together (such as the underarm or between fingers or toes).

Creams and lotions

If pruritus is related to dry skin, emollient creams or lotions may be used. Emollients help soothe and soften the skin and increase moisture levels in the skin. It is important to know the ingredients in these creams and lotions because some may cause skin reactions. Such ingredients include:

• Petrolatum, which is not well absorbed in skin treated with radiation therapy and may build up too much or be hard to remove.
• Lanolin, which may cause allergic reactions in some people.
• Mineral oil, which may be combined with petrolatum and lanolin in creams and lotions and may be an ingredient in bath oils.

Other ingredients added to emollients, such as thickeners, preservatives, fragrances, and colorings, may also cause allergic skin reactions.

Emollient creams or lotions are applied at least two or three times a day and after bathing. Gels with a local anesthetic (0.5%–5% lidocaine) can be used on some small areas as often as every 2 hours if you aren't sensitive to alcohol ingredients.

To soothe or cool areas of severe pruritus, over-the-counter products containing menthol, camphor, pramoxine, or capsaicin can be used. These products soothe, cool, and decrease the urge to scratch. Capsaicin-based therapies may work best in pruritus related to nerve signals.

Prescription drugs applied to the skin

Your doctor may prescribe topical steroids (steroids applied to the skin) to reduce itching, but they cause thinning of the skin and make it more sensitive. They should be used only for pruritus related to inflammation. Topical steroids should not be used on skin being treated with radiation therapy, but may be used to relieve inflamed skin after radiation treatment ends.

For xerosis (abnormally dry skin) or keratoderma (a horn-like skin condition), moisturizer creams may be used to seal in moisture and peel off scaly layers of skin. Humectants with ingredients like salicylic acid, ammonium lactate, or urea may improve skin smoothness but can cause stinging if applied to broken skin.

Systemic therapies

Systemic therapies travel through the bloodstream and reach and affect cells all over the body. They may help treat the condition causing your pruritus or help control your symptoms.

Your doctor may prescribe an antibiotic if your pruritus is caused by an infection. You may also be given an oral antihistamine to relieve itching. A larger dose may sometimes be used at bedtime to help you sleep.

Other drug therapies

If other drug treatments do not work to control pruritus, sedatives and antidepressants are sometimes used.

Aspirin may relieve pruritus in some patients with polycythemia vera but may increase pruritus in others. Cimetidine alone or combined with aspirin may help control pruritus in patients with Hodgkin lymphoma and polycythemia vera.

Comfort measures

Other steps may be taken to help you keep from scratching and stop the itch-scratch-itch cycle. These may include:

• Applying emollients to help prevent skin breakdown.
• A cool washcloth or ice held over the itchy area.
• Firm pressure on the itchy area, on the same area on the opposite side of the body, and at acupressure points.
• Rubbing or vibration on the itchy area.
• Transcutaneous electrical nerve stimulation (TENS) or acupuncture.

Treatment of pruritus in cancer patients involves learning what the triggers are and taking steps to avoid them.

It is important for you and for caregivers to know what triggers itching, such as dry skin or hot baths, so you can take steps to prevent it. You may need more than one type of treatment to relieve or prevent pruritus, protect your skin, and keep you comfortable.

Good nutrition is very important for healthy skin. A good diet includes a balance of proteins, carbohydrates, fats, vitamins, minerals, and fluids. Eating a balanced diet and drinking plenty of fluids helps your skin stay healthy. It is best to drink at least 3 liters (about 100 ounces) of fluid each day, but this may not be possible for everyone.

Washing the skin every day or every two days is important to help remove dirt and keep the skin healthy.

Many of us have experienced the sting of a bad sunburn and the itchy, peeling skin that follows. For decades, scientists suspected that pain and itch were the same thing, only expressed at different intensities: Itch was just light pain, and pain was strong itch.

Scientists have been trying to better understand how these sensations occur on a cellular level. Recent studies funded by the National Institutes of Health show that pain and itch stem from a complicated process involving many types of neurotransmitters, chemicals that transfer nerve signals to the brain, and receptors, cell surface proteins that accept those signals. A major goal of this line of research is to find better ways to tackle chronic pain and itch conditions, which often persist despite use of soothing medicines.

Defining Pain and Itch

Pain and itch are both forms of nociception, the sensing of danger through stimulus from the environment. At a basic level, pain tells the body that there either has been an injury or that one is imminent. Nociception is the reason why we feel a burning sensation when we get too close to a flame. Itch, clinically known as pruritus, signals that there is an irritant or potential toxin around.

In both cases, the skin is vital to signaling. Cells called keratinocytes live at the base of the epidermis, the surface layer of the skin, and send sensory signals to nearby nerve endings. If skin were a stone wall surrounding a town, then keratinocytes would be the watchtowers that alert the townspeople about approaching intruders. The nerve endings transmit the signal through circuits of multiple nerve cells toward the brain.

But pain is not limited to the skin. The same pain receptors exist on nerve endings inside the body, producing the sensation of an achy muscle or stomach cramp. That's not the case with itch receptors. They only go as far inside the body as the mucous membranes, such as inside our nostrils or throat. This is why our internal organs never seem itchy. If they did, imagine how hard they'd be to scratch!

Pain and itch can come about in different ways. Itch, for example, can be brought on by chemicals called histamines. Histamines are a critical part of the allergic reaction that we feel with a mosquito bite or with hives. Histamine-mediated itch can be relieved with an antihistamine. But the majority of chronic itch doesn't involve histamine, making it difficult to medicate. In fact, that sort of histamine-independent itch is a common side effect of pain medications such as morphine.

Scientists took this connection between pain and itch as another clue that the two are related, but they still weren't sure whether itch was simply dulled pain or a distinct sensation. They started looking for answers in the nerve cells.

Finding Pain and Itch

One answer comes from scientists at Johns Hopkins University. The researchers found two families of receptors on nerve cells that receive signals from keratinocytes: TRP receptors mediate pain and itch, and Mrgpr receptors mediate histamine-independent itch.

Scientists made these findings by turning off different types of receptors in mice, which have a similar nervous system to humans. By exposing the mice to chloroquine, an antimalarial drug that can cause itching as a side effect, and capsaicin, the "hot" compound in spicy peppers, they could tell what the mice sensed.

"If the mouse felt an itch, it would scratch behind its ears with its hind leg," says Xinzhong Dong, who led the study. "When it felt pain, it would rub its cheek with its front leg."

Mice lacking an Mrgpr "itch" receptor specific to chloroquine could feel pain but not itch. Mice that didn't have a TRP "pain" receptor that responds to capsaicin actually found capsaicin itchy instead of painful.

Dong explains that these findings indicate that neurons containing only the TRP receptor process pain sensation. On the other hand, neurons containing both the TRP receptor and the Mrgpr receptor transmit itch signals.

The results also suggest that pain circuits can inhibit itch circuits, so only one signal is sent at a time—explaining why pain and itch rarely happen simultaneously.

Today, researchers are pursuing drug compounds that directly block pain and itch receptors to deliver more targeted relief with fewer side effects.