Prurigo nodularis is the formation of hard, intensely itchy bumps on the skin. Scratching causes the skin to open.
Excessive scratching of an itch causes prurigo nodularis. The initial cause of the itch is not always clear, but it may be nerve problems.
Factors that may increase your risk of prurigo nodularis include:
- Psychological conditions
- Reduced function of the liver and kidneys
- Skin conditions that cause itching such as eczema
- Certain infections, such as hepatitis
- Type 2 diabetes mellitus
- Thyroid disorders
- Certain cancers, such as Hodgkin's disease
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Skin lumps are small (usually < 2 cm) and hard. The top of the lumps may be dry and peeling, or if it has been scratched, may be open and bleeding.
Scratching makes prurigo nodularis worse. Scratching can also cause damage to the surface of the skin and increase your risk of infection. Over time, there may also be some scarring.
A key sign of a prurigo nodularis lump is intense itching. The itching may be constant or sporadic.
You will be asked about your symptoms and your medical history. The diagnosis is usually made based on the appearance of your skin and your symptoms.
Your bodily fluids and tissues may be tested to check for other conditions. This can be done with:
- Blood tests
- Skin biopsy
Treatment may take time and involve different therapies until the right one is found. The goal is to reduce itchiness and prevent scratching.
Prurigo nodularis may be treated with:
- Topical medications that are applied to the skin, such as steroids, coal tar, vitamin D, or capsaicin
- Oral steroids or antihistimines
- Corticosteroid injections
- Medications that suppress or modify the immune system
- Antiseizure medications
If initial treatment does not work, the following options may be tried:
- Cryotherapy to freeze affected skin
- Pulsed dye laser
If prurigo nodularis affects quality of life or is treatment is not helpful, counseling may be needed to better manage the condition.
Work with your doctor to manage any skin conditions that cause itching.
If you have a skin condition or bug bite that is causing itching, then try to avoid scratching. Consider using over the counter itch medication or ask your doctor about ways to relieve the itching.
American Academy of Dermatology
Family Doctor—American Academy of Family Physicians
Canadian Dermatology Association
The Eczema Society of Canada
Fostini AC, Girolomoni G, et al. Prurigo nodularis: an update on etiopathogenesis and therapy. J Dermatolog Treat. 2013;24(6):458-462.
Lotti, T, Buggiani, G, Prignano F. Prurigo nodularis and lichen simplex chronicus. Dermatol Ther. 2008 Jan-Feb;21(1):42-6.
Nodular prurigo. DermNet NZ website. Available at: http://dermnetnz.org/dermatitis/prurigo-nodularis.html. Updated September 2014. Accessed August 18, 2017.
Prurigo nodularis. American Osteopathic College of Dermatology website. Available at: http://www.aocd.org/?page=prurigonodularis. Accessed August 18, 2017.
Prurigo nodularis Patient.co.uk website. Available at: http://www.patient.co.uk/doctor/Prurigo-Nodularis.htm. Updated January 28, 2016. Accessed August 18, 2017.
Last reviewed September 2018 by EBSCO Medical Review Board Michael Woods, MD FAAP Last Updated: 8/11/2015