Prurigo Nodularis

What is prurigo nodularis? Prurigo nodularis is a rare, chronic disease of the skin that is characterized by the development of extremely pruritic nodules. It primarily affects older adults.

What causes prurigo nodularis?

 

The pathogenesis of prurigo nodularis has not been completely elucidated but is thought to result from a combination of disordered functioning of the immune and nervous systems. It has been illustrated to develop as a reaction in some patients suffering from chronic pruritus, and continued scratching causes the lesions to thicken.

 

In older patients, prurigo nodularis is associated with conditions that affect multiple organ systems such as diabetes, cancer, chronic kidney disease, and AIDS. When it does affect a younger cohort, it is associated with other inflammatory skin diseases, such as atopic dermatitis. A number of neurological and psychiatric conditions, such as polyneuropathy and psychogenic pruritus, are associated with the development of prurigo nodularis. In addition, certain chemotherapeutic agents, including paclitaxel and carboplatin, are also implicated in the precipitation of prurigo nodularis.

 

Signs and symptoms of prurigo nodularis

 

  • Pruritic and symmetrically distributed rash that appears on areas that can be easily reached, such as the arms, legs, upper back, and/or abdomen.
  • Rash presents as firm dome-shaped nodules of varying shape and color.
  • Thickening of the affected skin and post-inflammatory scarring and hyperpigmentation.
  • Severe pruritus that can interfere with sleep and cause psychological distress.
  • Symptoms may be worsened with heat, sweat, certain clothing, and stress.

What treatments are available for prurigo nodularis?

Currently, there is no cure available for prurigo nodularis. However, management is possible through behavioral and medical treatment modalities.

 

Behavioral modifications include:

  • Preventing scratching by keeping fingernails short, wearing long sleeves and shirts, keeping lesions covered, and using anti-itch lotions such as calamine.
  • Decreasing xerosis by using gentle cleaners, keeping the skin moisturized, and avoiding activities and weather that cause sweating.

 

Medical treatments include:

  • Antihistamines
  • Topical or intralesional injections of corticosteroids.
  • Topical calcineurin inhibitors.
  • Topical Vitamin D.
  • Cryotherapy
  • Phototherapy using UVA and/or UVB.
  • SSRIs with psychotherapy
  • Gabapentin for those with severe nighttime symptoms.
  • Oral immunosuppressants for refractory cases.

Source: NORD – National Organization for Rare Disorders. (2021, June 28). Prurigo Nodularis. Retrieved February 6, 2022, from https://rarediseases.org/rare-diseases/prurigo-nodularis/#:%7E:text=Prurigo%20nodularis%20(PN)%20is%20a,with%20sleep%20and%20psychological%20wellbeing.