Itching is an irritating sensation in the skin that makes a person want to scratch.
Most people have itching from time to time. Often, there is no clear reason for the itching. Usually, the sensation goes away in a few seconds or after scratching. In some cases, however, itching can persist. The causes of continued itching range from mild to life threatening.
Itching has many possible causes. These may include:
Other causes are also possible. Sometimes, no cause can be found.
A healthcare provider will ask the person questions to learn more about the nature of the itching. These may include:
Other things may also be important in certain cases. For example, if a person has genital itching, information about his or her sexual activity or menstrual periods may be important.
The first step in figuring out the cause is a medical history and physical exam. This may be sufficient to make a diagnosis. In other cases, further tests may be needed.
The tests that are ordered will depend on the suspected cause of the itching. For example, blood tests can be used to help diagnose some blood cancers, hormone imbalances, and kidney failure. In cases of a skin rash, a biopsy of the skin may be needed. In this procedure, a small piece of skin is removed and sent to the lab for further testing. Special x-ray tests or other procedures may be needed in certain cases.
Prevention is related to the cause. For example, avoiding sunburn or poison ivy can prevent these causes of itching. Getting regular childhood vaccines can prevent chickenpox. Many cases cannot be prevented.
Severe itching can disrupt a person's life. Sleep and other activities may be difficult. Scratching of itchy areas can cause damage to the skin and may result in skin infection. Other long-term effects are related to the cause. For example, cancer can result in death. Multiple sclerosis can result in severe weakness and numbness in certain areas of the body. People with chronic renal failure may need a kidney transplant or dialysis.
Itching itself is not contagious. However, if the cause is an infection such as scabies or chickenpox, the infection may be contagious.
There are treatments available to reduce itching. Antihistamine medications such as hydroxyzine and diphenhydramine can be helpful. Another type of medication is topical corticosteroids such as hydrocortisone cream. Occasionally, oral corticosteroids such as prednisone are used for severe rashes. Other remedies such as calamine lotion are also available.
Treatment of the cause is also important, when possible. For example, antibiotics can be used to treat scabies. A thyroid hormone imbalance can often be corrected with medications. Surgery, chemotherapy, or radiation therapy may be needed to treat a tumor or cancer.
Side effects depend on the treatments used. All medications have possible side effects. For example, antihistamines can cause drowsiness or confusion.
Itching from sunburn or poison ivy will go away on its own and no further treatment is needed. Other cases may resolve with treatment, such itching caused by scabies.
Any change or response to treatment can be reported to the healthcare provider. Other monitoring is related to the cause. For example, people with thyroid hormone problems may need thyroid function tests to monitor their thyroid hormone level.
Author:Adam Brochert, MD
Editor:Slon, Stephanie, BA
Reviewer:Gail Hendrickson, RN, BS
Conn's Current Therapy, 1999, Rakel et al.