Parapsoriasis
In dermatology, parapsoriasis is "the term applied to a group of relatively uncommon inflammatory, maculopapular, scaly eruptions of unknown etiology and resistant to conventional treatment. Eruptions are both psoriatic and lichenoid in appearance, but the diseases are distinct from psoriasis, lichen planus, or other recognized dermatoses."[1]
Classification
There are two subgroups of parapsoriasis.
Pityriasis lichenoides
Pityriasis lichenoides is "a subgroup of parapsoriasis itself divided into acute and chronic forms."[2][3][4]
Acute pityriasis lichenoides is "the acute form is characterized by the abrupt onset of a generalized, reddish-brown, maculopapular eruption. Lesions may be vesicular, hemorrhagic, crusted, or necrotic. Histologically the disease is characterized by epidermal necrolysis."[2] The acute form is also called pityriasis lichenoides et varioliformis acuta (PLEVA) and includes Mucha-Habermann Disease.
Pityriasis lichenoides chronica is the chronic form which "shows milder skin changes with necrosis."[2]
Pityriasis lichenoides may evolve into cutaneous T cell lymphoma.[4]
Parapsoriasis en plaques
The parapsoriasis en plaques subgroup includes small- and large-plaque parapsoriasis.
Differential diagnosis
- Contact Dermatitis, Allergic [r]: Add brief definition or description
- Pityriasis Lichenoides [r]: Add brief definition or description
- Cutaneous T-Cell Lymphoma [r]: Add brief definition or description
- Pityriasis Rosea [r]: Add brief definition or description
- Nummular Dermatitis [r]: Add brief definition or description
- Psoriasis, Guttate [r]: Add brief definition or description
- Pityriasis Alba [r]: Add brief definition or description
- Syphilis [r]: Chronic infectious disease caused by a spirochete Treponema pallidum, either transmitted by direct contact, usually in sexual intercourse, or passed from mother to child in utero. [e]
References
- ↑ Anonymous (2024), Parapsoriasis (English). Medical Subject Headings. U.S. National Library of Medicine.
- ↑ 2.0 2.1 2.2 Anonymous (2024), Pityriasis lichenoides (English). Medical Subject Headings. U.S. National Library of Medicine.
- ↑ Khachemoune A, Blyumin ML (2007). "Pityriasis lichenoides: pathophysiology, classification, and treatment". Am J Clin Dermatol 8 (1): 29–36. PMID 17298104. [e]
- ↑ 4.0 4.1 Bowers S, Warshaw EM (October 2006). "Pityriasis lichenoides and its subtypes". J. Am. Acad. Dermatol. 55 (4): 557–72; quiz 573–6. DOI:10.1016/j.jaad.2005.07.058. PMID 17010734. Research Blogging.