Itchy skin is an uncomfortable, irritating sensation that makes you want to scratch. Also known as pruritus (proo-RIE-tus), itchy skin is usually caused by dry skin. It's common in older adults, as skin tends to become drier with age.

Depending on the cause of your itchy skin, it may appear normal. Or it may be red or rough or have bumps or blisters. Repeated scratching can cause raised, thickened areas of skin that may bleed or become infected.

Self-care measures such as moisturizing, using anti-itch products and taking cool baths can help relieve itchy skin. Long-term relief requires identifying and treating the cause of itchy skin. Itchy skin treatments include medications, wet dressings and light therapy.

Possible causes of itchy skin include:

Dry skin. If you don't see a crop of bright, red bumps or some other dramatic change in the itchy area, dry skin (xerosis) is a likely cause. Dry skin usually results from older age or environmental factors such as long-term use of air conditioning or central heating, and washing or bathing too much.
Skin conditions and rashes. Many skin conditions itch, including eczema (dermatitis), psoriasis, scabies, lice, chickenpox and hives. The itching usually affects specific areas and is accompanied by other signs, such as red, irritated skin or bumps and blisters.
Internal diseases. Itchy skin can be a symptom of an underlying illness. These include liver disease, kidney failure, iron deficiency anemia, thyroid problems and cancers, including leukemia and lymphoma. The itching usually affects the whole body. The skin may look otherwise normal except for the repeatedly scratched areas.
Nerve disorders. Conditions that affect the nervous system — such as multiple sclerosis, diabetes mellitus, pinched nerves and shingles (herpes zoster) — can cause itching.
Irritation and allergic reactions. Wool, chemicals, soaps and other substances can irritate the skin and cause itching. Sometimes the substance, such as poison ivy or cosmetics, causes an allergic reaction. Food allergies also may cause skin to itch.
Drugs. Reactions to drugs, such as antibiotics, antifungal drugs or narcotic pain medications, can cause widespread rashes and itching.
Pregnancy. During pregnancy, some women experience itchy skin, especially on the abdomen and thighs. Also, itchy skin conditions, such as dermatitis, can worsen during pregnancy.

Itching may be most noticeable at night (nocturnal), during the day, or both. When there are itching symptoms, there can be a leathery or scaly texture to the skin depending on the cause.

Itching can be caused by toxins on the skin (contact dermatitis, such as from poison ivy, poison oak, poison sumac, or grass oils), medications, liver disease, kidney disease, insect bites, hives (urticarial), rare forms of skin cancer (mycosis fungoides and T-cell lymphomas), infections (including chickenpox and fungal infections such as athlete's foot and jock itch), irritation from clothing, eczema, dermatitis herpetiformis, hemorrhoids, and many other conditions, or it can remain unexplained. Infectious causes of itching include sexually transmitted diseases (STDs), parasites (such as scabies, fleas, bedbugs, pinworms, and lice), and viral rashes.

There are many causes of diffuse and localized itching. Itching symptoms can be associated with

rash,
dry skin,
cracked skin,
flaky skin,
flaky scalp,
skin redness,
bumps on the skin,
blisters, or
spots on the skin.

Once a cause is identified, treatments for itchy skin may include:

Medications

Corticosteroid creams. If your skin is itchy and red, your doctor may suggest applying a medicated cream to the affected areas. He or she may also suggest that you cover these areas with damp cotton material that has been soaked in water or other solutions. The moisture in the wet dressings helps the skin absorb the cream and also has a cooling effect on the skin, reducing itch.
Calcineurin inhibitors. Certain drugs, such as tacrolimus (Protopic) and pimecrolimus (Elidel), can be used instead of corticosteroid creams in some cases, especially if the itchy area isn't large.
Antidepressants. Selective serotonin reuptake inhibitors, such as fluoxetine (Prozac) and sertraline (Zoloft), may help reduce various types of skin itching.
Treating the underlying disease

If an internal disease is found — whether it's kidney disease, iron deficiency or a thyroid problem — treating that disease often relieves the itch. Other itch-relief methods also may be recommended.

Light therapy (phototherapy)

Phototherapy involves exposing your skin to certain wavelengths of ultraviolet light. Multiple sessions are usually scheduled until the itching is under control.

Tracking down the cause of your itch can take time and involve a physical exam and a careful history. If your doctor suspects your itchy skin is the result of an underlying medical condition, he or she may perform tests, including:

Blood test. A complete blood count can provide evidence of an internal condition causing your itch, such as iron deficiency.
Tests of thyroid, liver and kidney function. Liver or kidney disorders and thyroid abnormalities, such as hyperthyroidism, may cause itching.
Chest X-rays. Signs of underlying disease that are associated with itchy skin, such as enlarged lymph nodes, can be seen by using X-rays.

Itching skin can affect the quality of your life. Prolonged itching and scratching may increase the intensity of the itch, possibly leading to:

Skin injury
Infection
Scarring