Pityriasis Rubra Pilaris

Pityriasis Rubra Pilaris is a topic covered in the 5-Minute Clinical Consult.

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Basics

Description

  • Pityriasis rubra pilaris (PRP) is a rare papulosquamous inflammatory skin condition characterized by red-orange scaly plaques, palmoplantar keratoderma, and follicular keratotic papules. In adults, lesions typically begin on the scalp, spreading to other areas of the body in a craniocaudal direction, and leaving characteristic islands of spared normal skin (“nappes claires”). PRP may progress to generalized erythroderma.
  • Divided into subtypes by Griffith classification (1): See “Physical Exam” section for descriptions.
    • Type I: classic adult
    • Type II: atypical adult
    • Type III: classic juvenile
    • Type IV: circumscribed juvenile
    • Type V: atypical juvenile
    • Type VI: HIV-associated PRP
  • In classic adult PRP, >80% of patients experience spontaneous resolution within 3 years. However, atypical adult and juvenile forms are chronic and intractable (2)[C].
  • Pediatric considerations: Lesions typically begin on the lower half of the body as opposed to adult presentations and may resemble seborrheic dermatitis. The 3-year remission rate is 32% (2)[C].

Epidemiology

  • Predominant age: bimodal distribution; most cases occur in the 1st and then the 5th to 7th decades of life, with the 6th to 7th being the most common decades for presentation (2)[C].
  • No gender predominance

Incidence
  • 1/400,000 patients
  • 1/3,500 to 5,000 patients presenting to dermatology clinics

Etiology and Pathophysiology

  • Unknown
  • Hypothesis that type III may be related to an abnormal immune response to an antigenic trigger
  • IL-23–TH17 axis has been implicated as a pathogenic inflammatory pathway.
  • Tumor necrosis factor (TNF) mRNA is elevated in PRP lesions similar to the level found in psoriasis, explaining the recent rise and potential value of anti-TNF agents in therapy (3).
  • Case reports also document this rash in postinfection states, including after streptococcal infections.
  • Some studies show that abnormal vitamin A metabolism and/or vitamin A deficiency may play some role in PRP etiology. However, others have not found any association.

Genetics

Familial occurrence has been described.

  • Familial type is most often autosomal dominant, but recessive forms have also been described.
  • Familial type associated with CARD14 mutation

General Prevention

No known preventive measures

Commonly Associated Conditions

  • Hypothyroidism
  • Seronegative arthritis
  • Myositis
  • Myasthenia gravis
  • Hypothyroidism
  • Celiac sprue
  • Infections, including HIV
  • Other autoimmune diseases
  • Malignancies

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Citation

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TY - ELEC T1 - Pityriasis Rubra Pilaris ID - 816337 ED - Baldor,Robert A, ED - Domino,Frank J, ED - Golding,Jeremy, ED - Stephens,Mark B, BT - 5-Minute Clinical Consult, Updating UR - https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/816337/all/Pityriasis_Rubra_Pilaris PB - Wolters Kluwer ET - 27 DB - Medicine Central DP - Unbound Medicine ER -