Itchy?

By Peter Galvin, MD
Chronic pruritis is defined as itching that lasts for six weeks or longer. It accounts for about seven million physician visits annually in the U.S. and affects about 22% of people during their lifetime. It is associated with impaired sleep and reduced quality of life. Some people with chronic pruritis have a “pure” itch – an uncomfortable sensation that results in an urge to scratch the skin. Others have pain or a burning, prickling, stinging, or crawling sensation on the skin. Symptoms may be mild, moderate, or severe, may occur at different times of the day or different seasons, and the skin may appear normal or may look reddened and inflamed. Itching may occur in response to various exposures such as water, sunlight, or pressure on the skin.
There are different types of chronic pruritis including:
- Inflammatory pruritis accounts for about 60% of cases and results from an immune system reaction due to conditions such as eczema, psoriasis, seborrheic dermatitis, and hives.
- Neuropathic pruritis is itching from nerve damage, for example a pinched nerve in the neck that causes itching across the middle of the back and backs of the arms, or nerve damage from shingles that causes itching in the affected areas. Diabetes may cause nerve damage that results in pain and itching. Intensely scratching an area of skin affected by nerve damage may provoke an immune system response.
- Other causes account for about 15% of chronic pruritis and include liver and kidney disease, medications such as opioids, amphetamine/dextroamphetamine, and immunotherapy drugs, and parasitic infestations such as scabies and ringworm.
People with chronic pruritis without a rash that lasts a year or more are more likely to have an underlying disease and should seek medical treatment and testing. About 90% of patients with chronic pruritis will respond to therapies applied directly to the skin (topical therapies). First line treatment for inflammatory pruritis includes topical anti-inflammatory medication such as hydrocortisone, triamcinolone, and tacrolimus ointment. Neuropathic itch can be treated with topical analgesics like menthol, pramoxine, and lidocaine. Sometimes a combination of these therapies will work. Those who do not respond to these therapies should be referred to a dermatologist, who may employ phototherapy, or exposure to UV light. Inflammatory pruritis may be treated with oral methotrexate or dupilumimab. Neuropathic cases may respond to advanced treatment with gabapentin, antidepressants like sertraline or doxepin, or opioid receptor agonists such as naltrexone or butorphanol.
Some cases may require alternative treatments such as reducing stress or anxiety, cognitive behavioral therapy, progressive muscle relaxation, transcutaneous electrical neurostimulation (TENS), acupuncture, or patient education. For more information go to the website of the American Academy of Family Physicians or the National Library of Medicine.
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