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Parapsoriasis (small plaque and large plaque parapsoriasis)

Laura Y McGirt, MD
Section Editor
John A Zic, MD
Deputy Editor
Rosamaria Corona, MD, DSc


The term "parapsoriasis" refers to a heterogeneous group of uncommon dermatoses occurring mainly in older adults and characterized by erythematous and scaly patches of variable size, chronic course, and resistance to treatment [1,2]. It is broadly divided in two main types: small plaque parapsoriasis (SPP) and large plaque parapsoriasis (LPP). In both types, lesions are typically asymptomatic or accompanied by mild pruritus and are predominantly located on the trunk. While SPP is generally considered a chronic benign condition, LPP is regarded as a premalignant dermatosis with a substantial risk of progression to mycosis fungoides, the most common type of cutaneous T cell lymphoma. (See "Clinical manifestations, pathologic features, and diagnosis of mycosis fungoides", section on 'Premycotic period'.)

SPP and LPP will be discussed in this topic. Other cutaneous lymphoproliferative disorders and mycosis fungoides are discussed separately.

(See "Pityriasis lichenoides chronica".)

(See "Pityriasis lichenoides et varioliformis acuta (PLEVA)".)

(See "Lymphomatoid papulosis".)

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Literature review current through: Oct 2017. | This topic last updated: Oct 14, 2016.
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