Itchy skin can affect small areas, such as the scalp, an arm or a leg. Or it can cover the whole body. Itchy skin can occur without any other noticeable changes on the skin. Or it may come with:

• Inflamed skin
• Scratch marks
• Bumps, spots or blisters
• Dry, cracked skin
• Leathery or scaly patches

Sometimes itchiness lasts a long time and can be intense. As you rub or scratch the area, it gets itchier. And the more it itches, the more you scratch. Breaking this itch-scratch cycle can be difficult.

When to see a doctor

See your health care provider or a skin disease specialist (dermatologist) if the itching:

• Lasts more than two weeks and doesn't improve with self-care measures
• Is severe and distracts you from your daily routines or prevents you from sleeping
• Comes on suddenly and can't be easily explained
• Affects your whole body
• Comes with other symptoms, such as weight loss, fever or night sweats

If the condition persists for three months despite treatment, see a dermatologist to be evaluated for skin disease. You may also need to see a doctor who specializes in internal medicine (internist) to check for other diseases.

Causes of itchy skin include:

• Skin conditions. Examples include dry skin (xerosis), eczema (dermatitis), psoriasis, scabies, parasites, burns, scars, insect bites and hives.
• Internal diseases. Itching on the whole body might be a symptom of an underlying illness, such as liver disease, kidney disease, anemia, diabetes, thyroid problems and certain cancers.
• Nerve disorders. Examples include multiple sclerosis, pinched nerves and shingles (herpes zoster).
• Psychiatric conditions. Examples include anxiety, obsessive-compulsive disorder and depression.
• Irritation and allergic reactions. Wool, chemicals, soaps and other things can irritate the skin and cause rashes and itching. Sometimes a substance, such as poison ivy or cosmetics, causes an allergic reaction. Also, reactions to certain medicines, such as narcotics to treat pain (opioids) can cause itchy skin.

Sometimes the cause of the itching can't be determined.

Itchy skin that is severe or lasts more than six weeks can affect the quality of your life. This type is called chronic pruritus. It might disturb your sleep or cause anxiety or depression. Prolonged itching and scratching can increase the intensity of the itch, possibly leading to skin injury, infection and scarring.

Diagnosing the cause of itchy skin starts with a physical exam and questions about your medical history. If your health care provider thinks your itchy skin is the result of a medical condition, you might have tests, including:

• Blood test. A complete blood count can provide evidence of an internal condition causing your itch, such as anemia.
• Tests of liver and kidney function. Liver or kidney disorders and thyroid conditions, such as hyperthyroidism, can cause itching.
• Chest X-rays. A chest X-ray can show if you have enlarged lymph nodes, which can go along with itchy skin.

Itchy skin treatment focuses on removing the cause of the itch. If home remedies don't ease your symptoms, your health care provider may recommend prescription medicine or other treatments. Controlling itchy skin symptoms can be challenging and may require long-term therapy. Options include:

• Corticosteroid creams and ointments. If your skin is itchy and inflamed, your health care provider may suggest applying a medicated cream or ointment to the affected areas. You might then cover the treated skin with damp cotton material. Moisture helps the skin absorb the cream and has a cooling effect.

  If you have severe or long-term itching, your health care provider might suggest this bedtime routine: Bathe in plain lukewarm water for 20 minutes, and then apply triamcinolone .025% to 0.1% ointment to the wet skin. This traps the moisture and helps the medicine absorb. Then put on pajamas. Repeat this routine at bedtime for several nights.

• Other creams and ointments. Other treatments that you apply to your skin include calcineurin inhibitors, such as tacrolimus (Protopic) and pimecrolimus (Elidel). Or you may find some relief with topical anesthetics, capsaicin cream or doxepin cream.
• Oral medicines. Antidepressants called selective serotonin reuptake inhibitors (SSRIs) may be helpful in easing some types of long-term itch. Examples of SSRIs include fluoxetine (Prozac) and sertraline (Zoloft). Another option is a tricyclic antidepressants, such as doxepin, You may not feel the full benefit of some of these medicines until 8 to 12 weeks after starting treatment.
• Light therapy (phototherapy). Phototherapy involves exposing your skin to a specific type of light. This can be a good option for people who can't take oral medicines. You'll likely need a few phototherapy sessions, until the itching is under control.

For temporary relief of itching, try these self-care measures:

• Avoid items or situations that cause you to itch. Try to identify what's causing your symptoms and avoid it. This might be wool clothing, an overly heated room, too many hot baths or exposure to a cleaning product.
• Moisturize daily. Apply hypoallergenic and fragrance-free moisturizer (Cetaphil, others) to affected skin at least once a day. For dry skin, thicker creams and ointments work better than lotions.
• Treat the scalp. For a dry, itchy scalp, try nonprescription medicated shampoos containing zinc pyrithione (Head & Shoulders, others), ketoconazole (Nizoral, others), selenium sulfide (Selsun Blue, others) or coal tar (Neutrogena T/Gel, others). You might need to try a few products before finding one that works for your hair and condition. Or you may find that switching between products helps. Don't use a medicated shampoo right after having a chemical relaxing process — rather, use a neutralizing shampoo.
• Use creams, lotions or gels that soothe and cool the skin. Short-term use of nonprescription corticosteroid cream may offer short-term relief of itchy, inflamed skin. Or try calamine lotion or creams with menthol (Sarna, others), camphor, capsaicin, or a topical anesthetic, such as pramoxine (adults only). Keeping these products in the refrigerator can enhance their soothing effect. Corticosteroid creams do not help with the itch that follows a shingles infection.
• Avoid scratching. Cover the itchy area if you can't keep from scratching it. Trim your nails and, if it helps, wear gloves when you sleep.
• Take a bath. Use lukewarm water and sprinkle in about a half cup (100 grams) of Epsom salts, baking soda or an oatmeal-based bath product (Aveeno, others). Use a mild cleanser (Dove, Olay, Cetaphil), limiting its use to the underarms and groin. Don't scrub too hard and limit your bathing time. Then rinse thoroughly, pat dry and moisturize.
• Reduce stress or anxiety. Stress or anxiety can worsen itching. Many people have found that counseling, behavior modification therapy, acupuncture, meditation and yoga can help reduce stress or anxiety.
• Try nonprescription oral allergy medicine. Some nonprescription allergy medicines (antihistamines), such as diphenhydramine, can make you drowsy. This type of pill might be helpful before bedtime if your itchy skin disrupts your sleep. Antihistamines do not help with the itch that follows a shingles infection.
• Use a humidifier. A humidifier may provide some relief if home heating causes the air in your home to be dry.
• Stay well rested. Getting enough sleep might reduce the risk of itchy skin.

You're likely to start by seeing your primary care provider. Or you may be referred to a specialist in skin diseases (dermatologist).

Here is information to help you get ready for your appointment and to know what to expect from your health care provider.

What you can do

List your symptoms, when they occurred, and how long they lasted. Also, list all medicines, vitamins and herbs you're taking. Or take the original bottles and a written list of the dosages and directions.

List questions to ask your health care provider. For itchy skin, questions you may want to ask include:

• What is likely causing my symptoms?
• Are tests needed to confirm the diagnosis?
• What are other possible causes for my symptoms?
• Is my condition likely short term or long term?
• What is the best course of action?
• I have other health problems. How can I manage them together?
• What are the alternatives to the primary approach you're suggesting?
• Do I need prescription medication, or can I use nonprescription products to treat the condition?
• What results can I expect?
• Can I wait to see if the condition goes away without treatment?

Don't hesitate to ask any other questions you have.

What to expect from your doctor

Your health care provider is likely to begin with your medical history and to ask you some questions, such as:

• When did you begin experiencing symptoms?
• What did your skin look like when your symptoms started?
• Have your symptoms changed?
• Is your itchiness interfering with your daily activities?
• What, if anything, appears to worsen your symptoms?
• What, if anything, appears to improve your symptoms?
• What at-home treatments have you tried?
• What prescription and nonprescription medicines are you taking?
• Have you traveled recently?
• Have you gone swimming or wading in a lake or pond recently?
• What is your typical diet?
• Are you in contact with possible irritants, such as pets or certain metals, at home or at work?