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].

• Asymptomatic

  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]

  Parapsoriasis is sometimes asymptomatic and requires treatment to avoid the risk of cancer. Topical corticosteroids can be applied in the moderate form of small plaque parapsoriasis. [icliniq.com]

  Associated with Hepatitis C virus infection[14] Sneddon–Wilkinson disease[15] Flaccid pustules that are often generalized and have a tendency to involve the flexural areas Annular configuration Pruritus May be asymptomatic Associated with: Monoclonal [wikidoc.org]

  It is generally asymptomatic or mildly pruritic. Patches exhibit parakeratosis and a sparse perivascular cutaneous lymphoid infiltrate primarily composed of CD4+ T cells. [unboundmedicine.com]

• Pathologist

  After inspection of the recorded files, the pathologists noted, were available, the localization and number of the lesions, together with symptoms. [ncbi.nlm.nih.gov]

  After histopathological features are evaluated by pathologists, dermoscopic correlations will be examined for each lesion. 30 patients with clinical and histopathological diagnosis of mycosis fungoides, and 30 patients with clinical and histopathological [clinicaltrials.gov]

  After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist arrives at a definitive diagnosis. [dovemed.com]

• Nausea

  SIDE EFFECTS The most common adverse reactions associated with sulfasalazine in ulcerative colitis are anorexia, headache, nausea, vomiting, gastric distress, and apparently reversible oligospermia. These occur in about one-third of the patients. [rxlist.com]

• Vomiting

  SIDE EFFECTS The most common adverse reactions associated with sulfasalazine in ulcerative colitis are anorexia, headache, nausea, vomiting, gastric distress, and apparently reversible oligospermia. These occur in about one-third of the patients. [rxlist.com]

• Arthralgia

  […] extremities Squamous marginal collarette and a “fir-tree” or “Christmas tree” distribution on posterior trunk Secondary to viral infections Resolves spontaneously after 6-8 weeks Preceded by a prodrome of: Sore throat Gastrointestinal disturbance Fever Arthralgia [wikidoc.org]

  […] erythematosus-like syndrome, hepatitis and hepatic necrosis with or without immune complexes, fulminant hepatitis, sometimes leading to liver transplantation, parapsoriasis varioliformis acuta (Mucha-Haberman syndrome), rhabdomyolysis, photosensitization, arthralgia [rxlist.com]

  However, some individuals may have headaches, fever, joint pain (arthralgia), and a general feeling or poor health (malaise). In some cases, swelling of nearby lymph nodes (lymphadenopathy) may also occur. [rarediseases.org]

• Dermatitis

  Figure 25-1 The relationship of clonal dermatitis to mycosis fungoides (MF) and various types of chronic dermatitis. [plasticsurgerykey.com]

  This has given rise to the concept of clonal dermatitis, originally described in the context of clonal non-specific chronic spongiotic dermatitis but later expanded to include other nonlymphomatous cutaneous T-cell infiltrates that harbor occult monoclonal [dermaamin.com]

  4 Chronic superficial scaly dermatitis with small regular patches Digitate lesions Download Figure: 5 Chronic superficial scaly dermatitis - probable A biopsy was suggestive of chronic superficial scaly dermatitis, however, with the sizeable and polymorphous [pcds.org.uk]

• Papule

  At the heart of the individual papules sometimes notice a small hemorrhage. [survinat.com]

  Symptoms: a rash in the form of pink nodules covered with scales of flat papules, light pink plaques with a yellowish tinge, red conical papules. [sanatoriums.com]

  Disease or Syndrome parapsoriasis Subclass of: Skin Diseases, Papulosquamous Definitions related to parapsoriasis: An inflammatory skin disorder of unknown etiology characterized by papules and plaques or scaly patches resembling psoriasis. [openmd.com]

  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 [symptoma.com]

  An inflammatory skin disorder of unknown etiology characterized by papules and plaques or scaly patches resembling psoriasis. [tabletwise.net]

• Eczema

  Through the use of chart reviews and a retrospective questionnaire, various factors (sex, age, history of eczema/atopy, occupation) were examined in these two patient groups. [ncbi.nlm.nih.gov]

  Parapsoriasis can be misdiagnosed with other more common diseases: tinea corporis, allergic contact dermatitis, psoriasis, nummular eczema, pityriasis rosea, syphilis… Therefore, it is important to see a doctor for an accurate diagnosis. [stamfordskin.com]

  Histologic Features: The features are very nonspecific, and distinction from early mycosis fungoides and eczema may be difficult. [dermpedia.org]

  I also use the cream on my hands for my eczema. I love it for that purpose, as well. Works wonderfully for my eczema (providing relief from itching and speeding healing) when I use it on my hands every night before bed. [amazon.es]

  With drop-shaped parapsoriasis markedly expressed parakeratosis, spongiosis, which may resemble seborrheic eczema or psoriasis, however it differs from the latter by vacuolar degeneration of the basal cells of the epidermis and expressed exocytosis of [iliveok.com]

• Chronic Dermatitis

  A 56-year-old black man had generalized chronic dermatitis for two years before parapsoriasis en plaque (large type) with hyper-IgE (12,000-22,000 ng/ml) was diagnosed. Lymphocyte cultures showed decreased response to mitogens. [ncbi.nlm.nih.gov]

  There are three main types of parapsoriasis: Pityriasis lichenoides Large plaque parapsoriasis (see separate chapter) Small plaque parapsoriasis (SPP) SPP is a rare, commonly benign chronic dermatitis most often seen in middle-aged men. [unboundmedicine.com]

  Common Causes of Parapsoriasis The following are the most common causes of Parapsoriasis: lymphoproliferative disorder ranging from development of chronic dermatitis to T-cell cutaneous lymphoma Prevention of Parapsoriasis Yes, it may be possible to prevent [tabletwise.net]

  The small-spot parapsoriasis is generally classified as indiopathic, benign, chronic dermatitis (some authors doubt the absolute "benignity" of small-spot parapsoriasis - see on this under Parapsoriasis en plaques benign small-spot form - and doubt an [altmeyers.org]

  Etiology and Pathogenesis It is likely that a complete understanding of the pathogenesis of parapsoriasis will develop with our understanding of the pathogenesis of both chronic dermatitis and mycosis fungoides (MF), because parapsoriasis appears to bridge [accessmedicine.mhmedical.com]

• Nummular Dermatitis

  Differential Diagnosis (Other conditions with similar appearance) Contact Dermatitis, Allergic Pityriasis lichenoides Cutaneous T-cell lymphoma Pityriasis rosea Nummular Dermatitis Psoriasis, Guttate Pityriasis alba Syphilis Diagnosis Key Points Initial [ozarkderm.com]

  Allergic contact dermatitis. Psoriasis. Guttate psoriasis. Nummular dermatitis. Nummular eczema. Pityriasis alba. Mycosis fungoides. Cutaneous T cell lymphoma. Pityriasis lichenoides. Syphilis. Pityriasis rosea. Erythroderma. Dermatomyositis. [icliniq.com]

  […] capped by a single detachable, opaque, mica-like scale Often leave hypopigmented macules High fever Malaise Myalgias Paraesthesia Pruritus Infection by any of the following:[6] Epstein-Barr virus (EBV) Toxoplasma gondii Human immunodeficiency virus (HIV) Nummular [wikidoc.org]

• Dizziness

  In rheumatoid arthritis studies, the following common adverse reactions were noted: nausea (19%), dyspepsia (13%), rash (13%), headache (9%), abdominal pain (8%), vomiting (8%), fever (5%), dizziness (4%), stomatitis (4%), pruritis (4%), abnormal liver [rxlist.com]

  […] scientifically even after his retirement in 1921; his last studies were brought to press shortly before his death in 1928. 1 Despite his capabilities as an observer of matters clinical, Brocq’s concepts of cutaneous diseases were, at times, nothing less than dizzying [derm101.com]

• Vertigo

  Central Nervous System reactions : transverse myelitis, convulsions, meningitis, transient lesions of the posterior spinal column, cauda equina syndrome, Guillain-Barre syndrome, peripheral neuropathy, mental depression, vertigo, hearing loss, insomnia [rxlist.com]

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.

• Human Herpesvirus 6

  Dermatology 207: 418-419 Erkek E et al (2002) Absence of Epstein-Barr virus and human herpesvirus-6 in pityriasis lichenoides and plaque parapsoriasis. [altmeyers.org]

  herpesvirus-6 in pityriasis lichenoides and plaque parapsoriasis. ( 12428859 ) Erkek E....Olut A.I. 2002 47 Demonstration of characteristic skin surface contours of extramammary Paget's disease and parapsoriasis en plaque by image analysis of negative [malacards.org]

• Lymphocytic Infiltrate

  In chronic lesions, there is a dense bandlike lymphocytic infiltrate, dermal fibrosis, basal vacuolar change and pigment incontinence. In all stages, the lymphocytic infiltrate is composed of monoclonal T-cells. [dermpedia.org]

  Abstract It has been demonstrated recently in mycosis fungoides and lichen planus that T lymphocyte subsets may be identified in cutaneous lymphocytic infiltrates using the immunoperoxidase technic in conjunction with monoclonal antibodies produced by [ncbi.nlm.nih.gov]

  This can produce an excess of one type of T cell or monoclonality of the lymphocytic infiltrate. Specific exposures or antigens have not been identified, although a viral etiology is suspected. [unboundmedicine.com]

METHODS: A retrospective study of treatment response in 116 patients diagnosed with MF and 71 patients with parapsoriasis and treated with topical nitrogen mustard from 1991 to 2009. [ncbi.nlm.nih.gov]

Parapsoriasis is resistant to all treatment. [medical-dictionary.thefreedictionary.com]

Although these various diseases have some similar clinical and histopathological features, they are obviously quite different from the standpoint of malignant potential and 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 The prognosis of SPP and LPP is unpredictable. This means follow-up visits with your healthcare provider are essential. [verywellhealth.com]

The term applied to a group of relatively uncommon inflammatory, maculopapular, scaly eruptions of unknown etiology and resistant to conventional treatment. [icd10data.com]

[…] 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]

National Cancer Institute, 2021 The term applied to a group of relatively uncommon inflammatory, maculopapular, scaly eruptions of unknown etiology and resistant to conventional treatment. [openmd.com]

Specific exposures or antigens have not been identified, although a viral etiology is suspected. Risk Factors Specific risk factors have not been identified. [unboundmedicine.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]

Last updated : September 6, 2019 Summary Epidemiology References:[1][2][3] Epidemiological data refers to the US, unless otherwise specified. [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 SPP most often presents in middle-aged men in the 5th decade of life, with a 3:1 ratio of men to women. [unboundmedicine.com]

Epidemiology No accurate statistics on the incidence and frequency Etiology Unknown Pathogenesis Develops from a few patches, which become more visible over time Clinical Small plaque – well-circumscribed, slightly scaly, light salmon-colored patches, [dermpathdiagnostics.com]

Etiology and Pathophysiology SPP is likely a reactive process in which a specific subset of T cells multiplies in response to a corresponding antigen. This can produce an excess of one type of T cell or monoclonality of the lymphocytic infiltrate. [unboundmedicine.com]

PDF Downloads: 0 (Spandidos Publications: | PMC Statistics: ) Abstract It has recently been demonstrated that γδ T lymphocytes play a role in innate immunity to the neoplastic process; however, the significance of this subset of T lymphocytes in the pathophysiology [spandidos-publications.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]

General Prevention No known preventative measures Commonly Associated Conditions CTCL, most often MF There's more to see -- the rest of this topic is available only to subscribers. [unboundmedicine.com]

Common Causes of Parapsoriasis The following are the most common causes of Parapsoriasis: lymphoproliferative disorder ranging from development of chronic dermatitis to T-cell cutaneous lymphoma Prevention of Parapsoriasis Yes, it may be possible to prevent [tabletwise.net]

Prevention There is no known way to prevent psoriasis. Keeping the skin clean and moist and avoiding your specific psoriasis triggers may help reduce the number of flare-ups. Doctors recommend daily baths or showers for persons with psoriasis. [checkorphan.org]

Prevention This skin disease can unfortunately not be prevented. [health.ccm.net]

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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.