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What is Prurigo Nodularis?

Itch Conditions/ Prurigo Nodularis
Prurigo nodularis is a rare, chronic inflammatory skin condition.

What are the symptoms?

Prurigo nodularis presents with numerous firm, itchy, dome-shaped nodules and lumps on the skin, usually in patients in their 40’s and 50’s. The itch in prurigo nodularis is thought to be more severe and intense than itch in either atopic dermatitis or psoriasis.
Prurigo nodularis
Figure 1. (a) Nodules in bilateral distribution on arms and (b) legs in a patient diagnosed with prurigo nodularis.
Symptoms to look for:
  • Severe, intense itchiness
  • Hard, itchy bumps on skin
  • Much like psoriasis, these bumps usually affect the extensor surfaces (such as the knees and elbows).
  • Patients may have just a few nodules, while others may have dozens.
  • Bumps can range in size from millimeter up to half an inch.
  • The skin overlying these bumps is often excoriated, meaning that they are peeling, open, and/or bleeding.
  • Can range in color from red to dark brown.
  • These bumps are usually symmetrically distributed, and much like psoriasis, commonly affect the extensor surfaces of the arms and legs and trunk. PN can occasionally affect the face, although this is more rare.

Common Questions

Is there a cure for prurigo nodularis?

There currently is no medication that completely cures prurigo nodularis. For more information on treating itch caused by prurigo nodularis visit our treatment page here.

Where does prurigo nodularis come from?

Prurigo nodularis is thought to result from the itch-scratch cycle, a vicious cycle of chronic itch followed by repeated scratching, which worsens the itch. While is it unclear what exactly triggers the itch-scratch cycle, it is believed that it arises from a combination of abnormalities in the nerve cells and immune components within the skin.
  • Research suggests that the distribution of nerves in the outer and inner layers of the skin is different in PN, and may affect how the skin responds to triggers.
  • Certain types of immune cells are found in higher numbers in patients with PN. These cells are thought to secrete chemical signals that cause inflammation and contribute to itch.
  • Further research is being done to better understand the cause of prurigo nodularis. Check out our research page by clicking here.

Who gets prurigo nodularis?

Prurigo nodularis can affect individuals of any age, but prurigo nodularis is most frequently seen in patients in their 50’s and 60’s. Females are more frequently affected than males. Patients with skin of color, including African American, Asian, and Hispanic patients, are at increased risk of developing prurigo nodularis compared to Caucasian patients.

Several medical conditions have also been found to lead to a greater risk of developing prurigo nodularis, including:
  • HIV infection
  • Iron deficiency
  • Renal failure
  • Certain allergic conditions, such as hay fever, asthma, and atopic dermatitis

Is prurigo nodularis contagious?

Prurigo nodularis is not an infectious disease; therefore, it is not contagious and cannot be passed from one person to another.

How is prurigo nodularis diagnosed?

Physicians can usually diagnose PN with a thorough skin examination and medical and family history. Rarely, a small skin biopsy or patch testing may be done to either establish a diagnosis or to rule out other skin diseases.