Itching is an intense, distracting irritation or tickling sensation that may be felt all over the skin's surface or confined to just one area. The medical term for itching is pruritus.
Itching leads most people instinctively to scratch the affected area. Different people can tolerate different amounts of itching, and anyone's threshold of tolerance can be changed due to stress, emotions, and other factors. In general, itching is more severe if the skin is warm, and if there are few distractions. This is why people tend to notice itching more at night.
Causes & symptoms
As of 2002, the recent discovery of itch-specific neurons (nerve cells) has given doctors a better understanding of the causes of the sensation of itching. Another factor that contributes to itching is the release of endogenous opioids in the body. While these chemicals function primarily to relieve pain, they also appear to enhance the sensation of itching. Although itching is the
Stress and emotional upset can make itching worse, no matter what the underlying cause. If emotional problems are the primary reason for feeling itchy, the condition is known as psychogenic itching. Some people become convinced that their itch is caused by a parasite or some medical disorder. This conviction is often linked to burning sensations in the tongue, and may be caused by a major psychiatric disorder.
Itching that occurs all over the body may indicate a medical condition such as diabetes mellitus, liver disease, kidney failure, jaundice, thyroid disorders, and rarely, cancer. Blood disorders such as leukemia, and lymphatic conditions such as Hodgkin's disease may sometimes cause itching as well.
Some people may develop an itch without a rash when they take certain drugs (such as aspirin, codeine, cocaine). Others may develop an itchy, red "drug rash" or hives because of an allergy to a specific drug.
A team of researchers in Texas has discovered that some people infected by Helicobacter pylori, a bacterium that causes gastritis, also develop itching that does not respond to usual treatments. When the bacterium is eradicated from the patient's digestive tract, the itching is relieved.
Itching also may be caused when hookworm larvae penetrate the skin. This type of itching includes swimmer's itch, creeping eruptions caused by cat or dog hookworm, and ground itch caused by the "true" hookworm.
Skin conditions that cause an itchy rash include:
- atopic dermatitis
- contact dermatitis
- dermatitis herpetiformis (occasionally)
- fungal infections (such as athlete's foot)
- hives (urticaria)
- insect bites
- lichen planus
- neurodermatitis (lichen simplex chronicus)
- psoriasis (occasionally)
Itching all over the body can be caused by something as simple as bathing too often, which removes the skin's natural oils and may make the skin too dry and scaly.
Specific itchy areas may occur if a person comes in contact with soaps, detergents, and wool or other rough-textured, scratchy material. Adults who have hemorrhoids, anal fissures, or persistent diarrhea may notice pruritus ani (itching around the anus). In children, itching in this area is most likely due to worms.
Intense itching called pruritus vulvae (itching of the external genitalia in women) may be due to a yeast infection, hormonal changes, contact dermatitis, or the use of certain spermicides, vaginal suppositories, ointments, or deodorants.
It's also common for older people to suffer from dry, itchy skin (especially on the back) for no obvious reason. Moreover, older people are more likely to develop itching as a side effect of prescription medications. Younger people may notice dry, itchy skin in cold weather. Itching is also a common complaint during pregnancy.
Itching is a symptom that is quite obvious to its victim. Someone who itches all over should seek medical care. Because itching can be caused by such a wide variety of triggers, a complete physical exam and medical history will help diagnose the underlying problem. A variety of blood and stool tests may help determine the underlying cause.
In general, itchy skin should be treated very gently. While scratching may temporarily ease the itch, in the long run scratching just makes it worse. In addition, scratching can lead to an endless cycle of more itching and scratching.
To control the urge to scratch, a person can apply a cooling or soothing lotion or cold compress to the area. Itching may be relieved by applying a warm compress of diluted vinegar, preferably such herbal vinegars as plantain, violet, lavender, or rose.
The itching associated with mosquito bites can be reduced by applying meat tenderizer paste, table salt (to wet skin), or toothpaste. Any alkaline preparation (like a paste of baking soda and water) will help ease the itch.
Probably the most common cause of itching is dry skin. Flaxseed oil and vitamin E taken orally can help to
- Don't wear tight clothes.
- Avoid synthetic fabrics.
- Don't take long baths.
- Wash the area in lukewarm water with a little baking soda.
- Take a lukewarm shower for generalized itching.
- Try a lukewarm oatmeal (or Aveeno) bath for generalized itching.
- Apply bath oil or lotion (without added colors or scents) right after bathing.
Practitioners of Chinese medicine utilize a wide variety of herbs as well as acupuncture and ear acupuncture to treat itching based upon the cause. The medicine Xiao Feng Zhi Yang Chong Ji (Eliminate Wind and Relieve Itching Infusion) can be taken three times daily to relieve itching. For external treatment of itching, the patient may bathe in Zhi Yang Xi Ji (Relieve Itching Washing Preparation) and apply She Chuang Zi Ding (Cnidium Tincture) and Zhi Yang Po Fen (Relieve Itching Powder).
In several small studies, transcutaneous electrical nerve stimulation (TENS) has been effective in temporarily relieving chronic itch associated with varying dermatoses. TENS is a treatment in which mild electrical current is passed through electrodes on the skin to stimulate nerves and block pain signals. Portable TENS units are available for home use.
Cutaneous field stimulation (CFS) was found to safely relieve experimentally induced itching for a longer time period than TENS. CFS electrically stimulates nerves in the skin to harmlessly mimic scratching and inhibit the itch sensation.
Herbal itch remedies
The following herbal remedies for itching are used externally:
- aloe vera
- bracken juice
- bird-of-paradise (Strelitzia reginae) flowers
- cabbage leaf poultice
- cattail (Typha latifolia) juice
- chickweed (Stellaria media) salve
- comfrey (Symphytum officinale) juice
- evening primrose (Oenothera biennis) oil
- heal-all (Prunella vulgaris) juice
- honeysuckle vine flowers and leaves
- marigold (Calendula officinalis)
- marsh mallow (Althaea officinalis) leaf poultice
- myrrh (Commiphora species) oil
- oats (Avena sativa) bath or poultice
- onion juice
- papaya fruit
- plantain (Plantago major) juice or poultice
- red pepper juice
- Sage (Salvia officinalis) leaves
- St. John's wort (Hypericum perforatum)
- tea tree (Melaleuca alternifolia) oil
- yellow dock (Rumex crispus) tea bath
Specific treatment of itching depends on the underlying cause. Such antihistamines as diphenhydramine (Benadryl) can help relieve itching caused by hives but won't affect itching from other causes. Most antihistamines also make people sleepy, which can help patients sleep who would otherwise be awake from the itch. Newer antihistamines that do not make people drowsy as a side effect are also available to treat itching.
Creams or ointments containing cortisone may help control itching from insect bites, contact dermatitis, or eczema. Cortisone cream should not be applied to the face unless a doctor prescribes it, and should not be used over the body for prolonged periods without a doctor's approval.
A newer medication that relieves the itching associated with burns as well as speeding the healing process is called dexpanthenol. Dexpanthenol helps to relieve the itching by preventing the affected skin from drying out.
Most cases of itching go away when the underlying cause is treated successfully.
Soaps are often irritating and drying to the skin and can make an itch worse. They should be avoided or used only when necessary. People who tend to have itchy skin should:
- Avoid bathing daily.
- Use lukewarm water when bathing.
- Use mild soap.
- Pat (not rub) the skin dry after bathing, leaving some water on the skin.
- Apply a moisturizer immediately after the bath but avoid lanolin products.
- Use a humidifier, particularly during heating season in colder climates.
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American Academy of Dermatology. 930 N. Meacham Rd., PO Box 4014, Schaumburg, IL 60168. (708) 330-0230.
Rebecca J. Frey, PhD