Itchy skin is a something we’ve all experienced from time to time, whether from an uncomfortable woolen sweater, seasonal dry skin or, perhaps, as a reaction to certain detergents or personal care products. Sometimes, when an itch lasts long enough—and is severe—it can lead to a condition called prurigo nodularis. A hallmark of prurigo nodularis is the development of firm bumps (called nodules) that intensify the itchiness. People with prurigo nodularis report itching that is so intense it disrupts sleep and prompts so much scratching that the skin begins to bleed.
Prurigo nodularis can affect people of any age, though is most common among those in middle age or older.
“Prurigo nodularis can be an extremely debilitating condition characterized by a relentless itch,” says Yale Medicine dermatologist Jeffrey Cohen, MD. “The condition can be very disruptive to patients’ lives, and addressing the itch to break the cycle of itching and scratching that can lead to prurigo nodularis is essential. This can be done in several ways, including with creams, pills, UV therapy, or injections.”
What is prurigo nodularis?
Prurigo nodularis is a chronic skin disorder characterized by the presence of hard, extremely itchy bumps known as nodules. Though the cause of the condition is unknown, the nodules are the result of persistent, intense scratching and rubbing of the skin. They tend to be found in easy-to-scratch areas such as the arms, legs, abdomen, and the upper and lower back. Difficult to reach places like the upper portion of the middle back are usually spared, and nodules generally do not form on the palms or soles of the feet, or face.
The formation of the nodules brings on more severe itching, triggering a cycle of more scratching and rubbing. In turn, this may lead to the formation of new nodules and even more itchy skin. The unrelenting scratching and rubbing does not allow the nodules to heal and can result in scarring. Breaking this itch-scratch cycle is a central aim of treatment.
Prurigo nodularis is not hereditary or contagious. It seems to affect males and females at equal rates, though there is limited data on how many people are affected by the condition.
What are the risk factors for prurigo nodularis?
Prurigo nodularis is often associated with underlying conditions that cause itchy skin, including other skin disorders such as atopic dermatitis or even insect bites. It also sometimes affects people who have certain underlying diseases, including kidney failure, HIV or hepatitis C infection, certain bacterial and parasitic infections, thyroid disease, lymphoma, and liver disease.
Sweating, heat, and emotional stress may worsen symptoms.
What are the symptoms of prurigo nodularis?
The main symptom of prurigo nodularis is the presence of firm, itchy nodules on the skin of the arms, legs, abdomen, and/or upper and lower back. The nodules can cause continuous or occasional episodes of severe itching.
The nodules can vary in size from a few millimeters to over three centimeters in diameter (approximately 0.2 inches to over 1.2 inches). Some people have just a few, while others have several hundred of them. They may be brown, red, or the same color as the rest of your skin. Once formed, nodules can persist for months or even years, and when they recede, they may leave behind dark- or light-colored scars.
How is prurigo nodularis diagnosed?
Your doctor will ask about your symptoms and whether you have any underlying medical conditions associated with prurigo nodularis. A physical exam will be done to check your skin for nodules and signs of scratching.
At this point, in many cases your doctor will be able to make a diagnosis. Medication may be prescribed to help relieve symptoms. Sometimes a skin biopsy may be required. This involves removal of a small piece of skin tissue, using a scalpel or other device. A pathologist will then examine the tissue sample under a microscope to confirm the diagnosis.
If your doctor diagnoses prurigo nodularis but the underlying cause of the condition is unknown, he or she may order bloodwork and other tests to evaluate liver, kidney, and thyroid function, and to check for HIV, hepatitis C, or parasitic infection.
How is prurigo nodularis treated?
Treatment of prurigo nodularis aims to eliminate or reduce the itchiness. The goal is to disrupt the itch-scratch cycle so that nodules and damaged skin can heal.
Lifestyle changes and over-the-counter medications. Certain lifestyle modifications and over-the-counter medications can help reduce and relieve itchy skin. These include:
- Try to avoid scratching nodules
- Use mild soaps or even no soap at all when bathing
- Apply skin moisturizer several times a day
- Apply over-the-counter lotions and ointments including capsaicin cream, pramoxine hydrochloride (a topical anesthetic), and products that contain camphor, menthol, and phenol to soothe skin and reduce itchiness
- Keep fingernails trimmed
- Wear gloves or mittens while sleeping to avoid unintentional scratching
Prescription medications. Various prescription medications can help manage symptoms.
- Corticosteroids. These can reduce inflammation and itchy skin. They may be topical (cream or ointment), oral, or injectable.
- Antihistamines. This medication can help reduce itchiness.
- Phototherapy. Exposing affected areas of skin to specific wavelengths of ultraviolet (UV) light may help reduce itchy skin and inflammation.
- Immunomodulatory drugs. By moderating the immune response, these medications reduce inflammation and itchy skin. Immunosuppressive drugs are usually reserved for more severe cases or for nodules that do not respond well to other treatments.
What is the outlook for people with prurigo nodularis?
For many, prurigo nodularis is a chronic condition that can persist for years. It can impair sleep and cause depression and anxiety. Treatment that helps reduce symptoms can be helpful in maintaining and improving quality of life.
What is unique about Yale Medicine's approach to prurigo nodularis?
“Prurigo nodularis can be extremely frustrating. At Yale Medicine, we take a compassionate approach to this condition to try to help patients do everything possible to stop the constant itch and discomfort,” says Dr. Cohen. “New treatments are coming out for prurigo nodularis and Yale Medicine dermatologists are experienced in using these new and effective treatments, as well as therapies that have provided benefit to patients for decades.”