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Parapsoriasis

Parapsoriasis is a term encompassing several disorders of the skin that possess a similar clinical presentation to psoriasis. They are considered to be lymphoproliferative in origin, as a number of patients progress to cutaneous T-cell lymphoma or mycosis fungoides. Pityriasis lichenoides, large plaque parapsoriasis (> than 5 cm in diameter) and small plaque parapsoriasis (< 5 cm) are the three main subtypes. The diagnosis is made on clinical grounds and a biopsy with a subsequent histopathological examination.


Presentation

The term parapsoriasis was initially coined more than 100 years ago and included pityriasis lichenoides, large plaque parapsoriasis, and small plaque parapsoriasis, which exhibit a similar clinical appearance but different etiology from psoriasis [1] [2]. The conditions that fit the clinical and histological description of parapsoriasis seem to represent a spectrum of a lymphoproliferative disorder because many studies have established that patients with either small plaque or large plaque psoriasis eventually progress to a T-cell cutaneous lymphoma (known as mycosis fungoides) [2] [3] [4]. Furthermore, infectious pathogens, such as human herpesvirus type 8 (HHV-8), were identified in a substantial number of lesions [5], implying that microorganisms might play an important role in the development of this clinical entity. As mentioned previously, three main subtypes of parapsoriasis are currently identified [1] [4] [6] [7]:

  • Pityriasis lichenoides - It is described as a rare disorder of the skin with several clinical forms - pityriasis lichenoides et varioliformis acuta (PLEVA), pityriasis lichenoides chronica (PLC) and febrile ulceronecrotic Mucha-Habermann disease (FUMHD) [7]. Main findings include an acute eruption of small red papules on multiple sites that may leave residual hypo/hyperpigmentation and scarring after resolution (PLEVA), a slower onset of flat macules and papules that are reddish-to-brown in color (PLC), or severe generalized eruption of necrotic plaques, ulcers, and purpuric lesions that has a 25% mortality rate (FUMHD) [7].
  • Small plaque parapsoriasis - The appearance of small (< 5 cm in diameter), pruritic macules, plaques, and patches on the extremities and the trunk in a relapsing and remitting fashion is the hallmark of small plaque parapsoriasis [1] [6]. They are more frequently encountered in middle-aged adults and a predominance toward male gender is observed [1] [6]. Digitate dermatosis, a separate type of small plaque parapsoriasis, is described when symmetrically distributed finger-like patches develop on the flanks [6].
  • Large plaque parapsoriasis - In addition to a larger diameter (> 5 cm, but many patients present with lesions of > 10 cm), atrophy of the plaques is a typical sign of large-plaque parapsoriasis. The lower extremities (thighs and buttocks), as well as the flexures of all extremities, are the main location where skin lesions appear [6]. Retiform parapsoriasis is a term used to describe a web-like disseminated pattern of lesions [1].
Candidiasis
  • Papular scabies insect bite reactions lichen planus miliaria keratosis pilaris lichen spinulosus transient acantholytic dermatosis lichen nitidus pityriasis lichenoides et varioliformis acuta Pustular acne vulgaris acne rosacea folliculitis impetigo candidiasis[en.wikipedia.org]
Aphthous Stomatitis
  • stomatitis oral candidiasis lichen planus leukoplakia pemphigus vulgaris mucous membrane pemphigoid cicatricial pemphigoid herpesvirus coxsackievirus syphilis systemic histoplasmosis squamous-cell carcinoma v t e Papulosquamous disorders ( L40–L45, 696[en.wikipedia.org]
Xanthoma
  • […] basal-cell carcinoma Merkel-cell carcinoma nevus sebaceous trichoepithelioma Pigmented Freckles lentigo melasma nevus melanoma Dermal and subcutaneous epidermal inclusion cyst hemangioma dermatofibroma (benign fibrous histiocytoma) keloid lipoma neurofibroma xanthoma[en.wikipedia.org]
Freckles
  • […] the skin and appendages by morphology Growths Epidermal wart callus seborrheic keratosis acrochordon molluscum contagiosum actinic keratosis squamous-cell carcinoma basal-cell carcinoma Merkel-cell carcinoma nevus sebaceous trichoepithelioma Pigmented Freckles[en.wikipedia.org]
Insect Bite
  • bite reactions lichen planus miliaria keratosis pilaris lichen spinulosus transient acantholytic dermatosis lichen nitidus pityriasis lichenoides et varioliformis acuta Pustular acne vulgaris acne rosacea folliculitis impetigo candidiasis gonococcemia[en.wikipedia.org]

Workup

A properly conducted physical examination and a meticulously obtained patient history are essential steps in making an initial diagnosis of parapsoriasis [6]. For this reason, physicians must obtain data regarding the progression of symptoms, their pattern of appearance (relapses, recurrences, etc.), and the location where they appear. A full inspection of the skin reveals crucial information about the lesions (their size, type, and stage), which is why the physical examination is perhaps the most important component of the workup. But because the diagnosis cannot be made solely on clinical grounds, and because progression to mycosis fungoides may occur in unrecognized patients (carrying a significantly poorer prognosis), a prompt sampling of the lesion and a histopathological evaluation is necessary. Small plaque parapsoriasis is distinguished by nonspecific epithelial hyperplasia, acanthosis, spongiosis, focal hyperkeratosis, and exocytosis [1] [6], whereas infiltration of lymphocytes, lichenoid findings, variable epithelial appearance (hyperplastic, atrophic, or even normal) and necrosis of keratinocytes are known hallmarks of large plaque parapsoriasis [1] [6]. However, lymphocytic infiltrates (although much milder) in the dermis have been identified in small plaque parapsoriasis as well [1], illustrating the frequent histological overlapping of the parapsoriasis subtypes.

Treatment

  • Treatment with 311-nm UV-B was given 3 to 4 times a week for 5 to 10 weeks.[ncbi.nlm.nih.gov]
  • Treatment of Parapsoriasis Parapsoriasis can be managed conservatively on the basis of symptoms, and often, topical treatment is effective. A novel treatment of parapsoriasis reported in 2018 is hydrogen-water bathing.[emedicine.com]

Prognosis

  • The use of such studies of T-cell subsets on in situ cutaneous lymphoid infiltrates may demonstrate a correlation with cytomorphology, clinical stage, and disease prognosis.[ncbi.nlm.nih.gov]
  • The prognosis of LPP is related to the progression and treatment of underlying mycoses fungoides Nevertheless, individuals with milder signs and symptoms have a better prognosis than those with severe signs and symptoms Regular follow up visits with the[dovemed.com]
  • Prognosis - Parapsoriasis Psoriasis is a life-long condition that can be controlled with treatment. It may go away for a long time and then return. With appropriate treatment, it usually does not affect your general physical health.[checkorphan.org]

Etiology

  • […] characterized by papules and plaques or scaly patches resembling psoriasis The term applied to a group of relatively uncommon inflammatory, maculopapular, scaly eruptions of unknown etiology and resistant to conventional treatment.[icd9data.com]
  • Abstract The term parapsoriasis refers to a group of chronic asymptomatic scaly dermatoses of unknown etiology about which there is still controversy over the nosology and nomenclature of the different conditions that comprise the group, particularly[ncbi.nlm.nih.gov]
  • The term applied to a group of relatively uncommon inflammatory, maculopapular, scaly eruptions of unknown etiology and resistant to conventional treatment.[icd10data.com]
  • Etiology and Pathophysiology LPP is a chronic inflammatory disorder likely caused by long-term stimulation of a specific subset of T cells by a corresponding antigen.[unboundmedicine.com]

Epidemiology

  • Epidemiology Epidemiological data refers to the US, unless otherwise specified. Etiology The term “parapsoriasis” has its roots in its dermatological similarity to psoriatic lesions (e.g., plaques and scaly patches) seen during efflorescence .[amboss.com]
  • AIM: The aim of the study was to investigate the epidemiological and morphological data of parapsoriasis cases diagnosed at Emergency City Hospital, Timisoara, Romania for a period of 12 years.[ncbi.nlm.nih.gov]
  • Epidemiology Incidence There are no good data reflecting the true incidence of LPP.[unboundmedicine.com]
  • Again, because this disorder is difficult to diagnose, there are no concrete epidemiological statistics. But, of those with LPP, about 10% will progress to a malignant form. The cause of parapsoriasis is unknown.[aocd.org]
Sex distribution
Age distribution

Pathophysiology

  • Etiology and Pathophysiology LPP is a chronic inflammatory disorder likely caused by long-term stimulation of a specific subset of T cells by a corresponding antigen.[unboundmedicine.com]
  • Pathophysiology of Parapsoriasis The initiating cause of parapsoriasis is unknown, but the diseases likely represent different stages in a continuum of lymphoproliferative disorders from chronic dermatitis to frank malignancy of cutaneous T-cell lymphoma[emedicine.com]

Prevention

  • Prevention This skin disease can unfortunately not be prevented.[health.ccm.net]
  • General Prevention There are no known preventative measures.[unboundmedicine.com]
  • Prevention - Parapsoriasis Diagnosis - Parapsoriasis Sometimes, a skin biopsy is done to rule out other possible conditions. If you have joint pain, your doctor may order x-rays.[checkorphan.org]

References

Article

  1. Baderca F, Chiticariu E, Baudis M, Solovan C. Biopsying parapsoriasis: quo vadis? Are morphological stains enough or are ancillary tests needed? Rom J Morphol Embryol. 2014;55(3 Suppl):1085-1092.
  2. Sarveswari KN, Yesudian P. The conundrum of parapsoriasis versus patch stage of mycosis fungoides. Indian J Dermatol Venereol Leprol. 2009;75(3):229-235.
  3. Väkevä L, Sarna S, Vaalasti A, Pukkala E, Kariniemi AL, Ranki A. A retrospective study of the probability of the evolution of parapsoriasis en plaques into mycosis fungoides. Acta Derm Venereol. 2005;85(4):318-323.
  4. Salava A, Pereira P, Aho V, et al. Skin Microbiome in Small- and Large-plaque Parapsoriasis. Acta Derm Venereol. 2017 Feb 8.
  5. Kreuter A, Bischoff S, Skrygan M, et al. High association of human herpesvirus 8 in large-plaque parapsoriasis and mycosis fungoides. Arch Dermatol. 2008;144(8):1011–1016.
  6. Lewin J, Latkowski JA. Digitate dermatosis (small-plaque parapsoriasis). Dermatol Online J. 2012;18(12):3.
  7. Khachemoune A, Blyumin ML. Pityriasis lichenoides: pathophysiology, classification, and treatment. Am J Clin Dermatol. 2007;8(1):29-36.

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Last updated: 2019-07-11 22:12