Last updated: May 15, 2023

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.

Epidemiologytoggle arrow icon

  • Rare disorder
  • Sex: >


Epidemiological data refers to the US, unless otherwise specified.

Etiologytoggle arrow icon

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


Small plaque parapsoriasistoggle arrow icon

  • 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


Large plaque parapsoriasistoggle arrow icon


Differential diagnosestoggle arrow icon


The differential diagnoses listed here are not exhaustive.

Referencestoggle arrow icon

  1. McGirt LY. Parapsoriasis (Small Plaque and Large Plaque Parapsoriasis). In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. Last 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.

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