Prurigo nodularis (PN) is an itchy skin disease that often develops alongside other medical disorders. It is linked to inflammation caused by immune system reactions within the skin.
Also called nodular prurigo, PN is not very common — though it may be underdiagnosed. Within the U.S., more than 87,000 people are diagnosed with prurigo nodularis each year. PN is typically treated with medications that reduce itching.
PN usually leads to intense itching. This itching, also called pruritus, may be a constant sensation, or it may come and go.
Scratching the itchy areas eventually causes nodules (bumps) and scaly skin patches to form. The nodules can then lead to additional itching, leading to an itch-scratch cycle: The more you scratch, the more you itch, driving you to scratch even more.
PN nodules may:
PN nodules can develop anywhere on the body that can be easily scratched, such as the upper and lower back, abdomen, arms, or legs. The skin lesions are often symmetrical — for example, you may have bumps in a similar location on both arms.
People with PN may also experience other indirect symptoms because of their intense itching or skin appearance. Some people may have trouble sleeping, need to miss school or work, or have feelings of depression or low self-esteem.
Researchers don’t know what causes prurigo nodularis. PN may develop as a result of immune system changes. It may also be linked to overactive or abnormal numbers of nerves in your skin.
People with certain risk factors are more likely to develop the condition. While PN can occur at any age, it is most often diagnosed in people between the ages of 51 and 65. Additionally, African Americans are more than three times more likely to develop PN, according to NORD.
People with certain chronic health conditions are also more likely to have prurigo nodularis.
Prurigo nodularis may develop in people who have underlying skin disorders like:
PN can also be caused by other health conditions, including diabetes, anemia (low levels of red blood cells), gout, or diseases that affect the thyroid, liver, or kidneys. Cancer — including liver cancer, lung cancer, skin cancer, and blood cancers like leukemia and lymphoma — can also increase your risk of PN.
Certain types of medications, such as cancer drugs, antimalarial drugs, or opioids, can also cause itching as a side effect, which sometimes leads to the development of prurigo nodularis.
Having PN doesn’t necessarily mean that you have another serious disease. PN can occur in people who don’t have any other known health problems. However, it is important to talk to your doctor about whether it might be a good idea to check for any other conditions, especially if you have other symptoms in addition to itchy skin and nodules.
Prurigo nodularis can be diagnosed by a dermatologist (a specialist in skin conditions).
PN may appear similar to other conditions such as pemphigoid nodularis or psoriasis. A dermatologist can diagnose skin problems by asking you questions about which symptoms you have, how often they appear, and how they affect your life.
If you are experiencing itchy skin or nodules, your dermatologist may perform various tests. They may perform a skin scraping in which they scrape off the top layer of skin cells to be studied under a microscope for the presence of fungus. Your doctor may also recommend a skin biopsy, in which a small sample of tissue is removed so it can be more carefully analyzed under the microscope. A biopsy can help your dermatologist identify skin changes such as hyperkeratosis and inflammation.
PN is often linked to other medical conditions, so your doctor may also recommend that you undergo additional tests to check for any other health problems.
PN is typically treated by a dermatologist. If PN is linked to another underlying medical issue, a dermatologist may also refer you to a specialist to treat the related condition.
PN treatments typically include medication. Finding a skin care routine that helps protect your skin is also important. Additionally, your dermatologist may recommend strategies to help you stop scratching.
Treatment of prurigo nodularis often includes creams or ointments that lessen the itching. Some of these creams, including treatments that contain menthol, phenol, or capsaicin, are available over-the-counter. If these don’t provide relief, your doctor may prescribe topical medications (drugs applied to the skin) like:
Other medications may also help. Corticosteroids such as triamcinolone acetonide (Kenalog-40) can also be given as an injection under your affected skin areas.
PN is also sometimes treated with oral medications (drugs taken by mouth as a pill or tablet). These medications often work by calming your immune system or preventing nerve fibers from sending itch signals to your brain. Some medications that can help with PN include:
Cryosurgery may be an option if other treatments aren’t effective. This treatment involves using extreme cold substances, such as liquid nitrogen, to “burn away” the nodules or abnormal skin areas. You may need to go through multiple cryosurgery procedures to get relief. This treatment option may not be a good fit for everyone, as it can lead to pain, light spots, or scarring.
Some people manage their PN using phototherapy — treatments using ultraviolet (UV) light. This may be an effective treatment when topical drugs don’t work or when large parts of your body are affected by PN. Another type of light treatment involves using a laser to treat the skin.
Treating any underlying conditions may also help improve prurigo nodularis. Additionally, because many people with PN experience depression and anxiety, treatments such as counseling or taking antidepressants can help improve your quality of life.
It can be very difficult to avoid scratching when you have PN. However, scratching at your nodules can lead to infection, cause new nodules to develop, and make treatment less effective.
You may find that certain things are likely to make your PN itching worse. Common triggers include heat, humidity, sweating, dry skin, stress, or certain types of fabric. Identifying and avoiding triggering factors may help you better manage your PN.
It may help to wear long-sleeved shirts and pants or to cover the affected skin with special medicated tape. You may also want to cut your fingernails very short or wear gloves to prevent deep scratches.
Staying active and busy may also help take your mind off the itching. Try to participate in work, hobbies, or activities that require you to focus on other things.
To improve sleep, taking sedating antihistamines can help reduce itch and help you get quality rest.
You may also need to take care of your skin by moisturizing with fragrance-free products and only using soaps that are designed for sensitive skin.
PN often lasts for several years. There are many potential treatments, and you may need to try multiple medications, other treatments, and lifestyle changes before you find something that works for you and improves your well-being.
On MyPrurigoTeam, the social network for people with prurigo nodularis and their loved ones, members come together to ask questions, give advice, and share their stories with others who understand life with prurigo nodularis.
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