Causes

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, multiple myeloma or lymphoma.
• 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 substances can irritate the skin and cause rashes and itching. Sometimes the substance, such as poison ivy or cosmetics, causes an allergic reaction. Also, reactions to certain drugs, such as narcotic pain medications (opioids) can cause itchy skin.

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