The exact cause of prurigo nodularis is not clear. The bumps are more likely form where skin has been scratched or irritated. Nerve problems may play a role.

Risk Factors

Prurigo nodularis is most common in adults between 20 to 60 years old. Things that may raise the risk are:

Mental health problems
Reduced function of the liver and kidneys
Skin conditions that cause itching such as eczema
HIV
Certain infections, such as hepatitis
Type 2 diabetes
Thyroid disorders
Certain cancers, such as Hodgkin's disease

Symptoms

Symptoms of prurigo nodularis are skin lumps that:

Are small, hard, and very itchy
May be dry and peeling at the top
May open and bleed when scratched

Itching may come and go or be constant. Scratching makes symptoms worse. Over time, there may also be some scarring.

Diagnosis

The doctor will ask about symptoms and past health. The diagnosis is usually based on symptoms and a skin exam.

Tests may be done to check for other conditions. They may include:

Blood tests
Skin biopsy

Treatment

It may take some time to find the right treatment. The goal is to ease itching and prevent scratching.

Prurigo nodularis may be treated with:

Medicines applied to the skin, such as steroids, coal tar, vitamin D, or capsaicin
Steroids or antihistamines taken by mouth
Corticosteroid injections
Medicines to change the immune system
Antidepressants
Antiseizure medicines
Antiemetics

If these treatments do not work, other options may be tried such as:

Cryotherapy—freezes affected skin
Phototherapy—applies UV light
Pulsed dye laser—uses a beam of light

The condition can be stressful. Counseling may help.

Prevention

There are no guidelines to prevent this condition. It may help to not scratch skin conditions and bug bites.

RESOURCES:

American Academy of Dermatology
http://www.aad.org

Family Doctor—American Academy of Family Physicians
http://familydoctor.org

CANADIAN RESOURCES:

Canadian Dermatology Association
http://www.dermatology.ca

The Eczema Society of Canada
http://eczemahelp.ca

References:

Prurigo nodularis. American Osteopathic College of Dermatology website. Available at: https://www.aocd.org/page/prurigonodularis. Accessed August 4, 2021.

Pruritis (Generalized). EBSCO DynaMed website. Available at: https://www.dynamed.com/approach-to/pruritus-generalized. Accessed August 4, 2021.

Williams KA, Huang AH, et al. Prurigo nodularis: Pathogenesis and management. J Am Acad Dermatol. 2020;83(6):1567-1575.

Last reviewed July 2021 by EBSCO Medical Review Board Dan Ostrovsky, MD
Last Updated: 8/4/2021

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