Last updated: September 6, 2019

Summarytoggle arrow icon

The term “parapsoriasis” covers a large group of idiopathic cutaneous diseases characterized by asymptomatic or mildly pruritic, erythematous, scaly patches, and a chronic course. The condition is roughly classified into two types: large plaque parapsoriasis and small plaque parapsoriasis. Large plaque parapsoriasis is considered a premalignant condition that can progress to mycosis fungoides. Diagnosis is based on clinical examination and histopathological findings on biopsy. Treatment includes topical steroid therapy and phototherapy.

  • Rare disorder
  • Sex: >


Epidemiological data refers to the US, unless otherwise specified.

  • Group of cutaneous diseases of unknown etiology
  • Skin lesions (i.e., papules, patches, or plaques) caused by T-cell infiltration into the skin

The term “parapsoriasis” has its roots in its dermatological similarity to psoriatic lesions (e.g., plaques and scaly patches) seen during efflorescence.


  • Clinical features
    • Round or oval, scaly, salmon-colored or yellow-brown patches
      • Size: < 5 cm diameter
      • Location: trunk, flanks, proximal extremities in non-sun exposed areas
    • Benign; chronic course (months to years); resolves spontaneously
  • Diagnostics: Skin biopsy
  • Treatment




The differential diagnoses listed here are not exhaustive.

  1. McGirt LY. Parapsoriasis (Small Plaque and Large Plaque Parapsoriasis). In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. updated: October 14, 2016. Accessed: December 18, 2017.
  2. Wong HK. Parapsoriasis. In: Elston DM, Parapsoriasis. New York, NY: WebMD. Updated: July 5, 2016. Accessed: December 18, 2017.
  3. Parapsoriasis. . Accessed: December 18, 2017.
  4. Parapsoriasis. Updated: January 1, 2017. Accessed: December 18, 2017.

3 free articles remaining

You have 3 free member-only articles left this month. Sign up and get unlimited access.
 Evidence-based content, created and peer-reviewed by physicians. Read the disclaimer