CAUSES

Several factors are thought to contribute to the development of PN. While the exact causes are not fully understood, research points to dysregulation of the immune system, nerves, and skin as playing a role.1

Altered immune function

PN is linked to an imbalance in the immune system, specifically an excess of type 2 inflammation.2 This type of immune response typically helps fight parasites. However, in individuals with PN, certain immune cells and proteins might be overly active, causing nerves to respond excessively to various stimuli. This results in skin inflammation and intense itching.3

Nerve abnormalities

PN arises from a malfunction in the nerve pathways that carry itch signals to your brain. Instead of transmitting accurate signals, these pathways become hypersensitive, triggering intense itching sensations even in the absence of trigger factors. Additionally, there is also an increase in the number of nerve fibers in affected skin areas. This combination leads to an enhanced itching sensation.3,4

Impaired skin barrier

In PN, the skin barrier may be compromised, allowing environmental irritants, microbes or allergens to penetrate the skin, leading to inflammation and itching. The act of scratching further damages the skin barrier, perpetuating a vicious itch-scratch cycle.5,6 Persistent scratching and picking of the skin contributes to further lesion thickening and formation of bumps seen in the disease.1,7

About PN

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Signs & Symptoms

There are multiple signs and symptoms associated with PN. See what they are and how they can present.

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Treatment & Management

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dermatologist to find the best way to
manage your PN. Learn more here.

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Reference:

  1. National Organization for Rare Diseases. Prurigo Nodularis. Available at: https://rarediseases.org/rare-diseases/prurigo-nodularis/. Accessed August 2023.
  2. Garcovich S, et al. Vaccines (Basel) 2021;9(3):303.
  3. Williams KA et al. J Am Acad Dermatol 2020; 83(6): 1567–1575.
  4. Kowalski EH et al. Clin Cosmet Investig Dermatol 2019;12:163–172.
  5. DermNet NZ. Nodular prurigo. Available at: https://dermnetnz.org/topics/nodularprurigo. Accessed: August 2023.
  6. Fölster-Holst R, et al. Biology (Basel) 2021;10(10):1008.
  7. American Academy of Dermatology Association. Prurigo nodularis: Signs and symptoms. Available at: https://www.aad.org/public/diseases/a-z/prurigo-nodularis-symptoms. Accessed August 2023.

The health information contained herein is provided for general educational purposes only. Your healthcare professional is the single best source of information regarding your health. Please consult your healthcare professional if you have any questions about your health or treatment.