What is pityriasis lichenoides?

Pityriasis lichenoides (PL) is an uncommon skin rash. PL has two main forms: Pityriasis lichenoides et varioliformis acuta (PLEVA): this "acute" (fast) form comes on quickly. Pityriasis lichenoides chronica (PLC): this "chronic" (long) form often develops slowly and lasts longer.

¿Qué Es la Pitiriasis Liquenoide?

La pitiriasis liquenoide (PL) es una erupción cutánea poco frecuente. La PL se presenta en dos formas básicas: La pityriasis lichenoides et varioliformis acuta (PLEVA): esta forma "aguda" (veloz) aparece rápidamente. La pityriasis lichenoides chronica (PLC): esta forma "crónica" (prolongada) a menudo se desarrolla lentamente y tiene una mayor duración.

Dermoscopy as a diagnostic aid in pityriasis lichenoides et varioliformis acuta.

Diagnosis of pityriasis lichenoides et varioliformis acuta (PLEVA) is based on the characteristic pattern of lesions in different stages of development, ranging from erythematous maculopapules to papules with a crusted and/or necrotic centre. However, it may raise the differential diagnosis with other entities. It is therefore not uncommon to have to perform skin biopsies to reach a diagnosis, including in infants. In this study, we report the cases of three patients with PLEVA, highlighting the correlations between the clinical, dermoscopic and histological features. Observation of the dermatoscopic findings described, such as punctate or glomerular vessels and erythematous globules surrounding a homogeneous orange or crusty central area, may allow for a rapid diagnosis, avoiding the need for invasive techniques.

Acute lichenoid and varioliform pityriasis in a pediatric patient.

BACKGROUND: Pityriasis lichenoides et varioliformis acuta (PLEVA) is a rare dermatosis recognized as a benign condition of unknown etiopathogenesis. It is more common in pediatric patients and young adults and is characterized by multiple small or large erythematous plaques spread over the trunk and extremities. CASE REPORT: We describe the case of a 5-year-old male, previously healthy, with multiple erythematous lesions that disappeared leaving hypopigmented macules. The biopsy reported histological changes suggestive of mycosis fungoides. After a second revision of lamellae in this hospital, lymphocytic vasculitis (LV) with focal epidermal necrosis consistent with acute pityriasis lichenoides (PL) was identified. CONCLUSIONS: The existing knowledge about PLEVA lacks a consensus in specifying its classification, etiopathogenesis, diagnosis, and treatment, so this clinical condition represents a medical challenge. The diagnosis is made by clinical suspicion and confirmed by histology. The objective of this article was to report a case of PLEVA with an atypical presentation due to its histopathological findings, being the first report showing LV in children, as well as a review of the literature.

INTRODUCCIÓN: La pitiriasis liquenoide y varioliforme aguda (PLEVA) es una dermatosis poco frecuente, de etiopatogenia desconocida y evolución autolimitada. Es más común en pacientes pediátricos y adultos jóvenes, y está caracterizada por la presencia de múltiples placas eritematoescamosas pequeñas o grandes, diseminadas en el tronco y las extremidades. CASO CLÍNICO: Se describe el caso de un escolar de 5 años, de sexo masculino, previamente sano, que presentó múltiples cuadros de lesiones eritematosas que desaparecían dejando máculas hipopigmentadas. La biopsia reportó cambios histológicos sugestivos de micosis fungoide. Se realizó una segunda revisión de laminillas, identificando vasculitis linfocítica con necrosis epidérmica focal, consistente con pitiriasis liquenoide aguda. CONCLUSIONES: El conocimiento acerca de la PLEVA carece de un consenso que especifique su clasificación, etiopatogenia, diagnóstico y tratamiento, por lo que esta condición clínica representa un desafío médico. El diagnóstico se realiza por sospecha clínica y se confirma por histología. El objetivo de este artículo fue reportar un caso de PLEVA con presentación atípica por los hallazgos histopatológicos, siendo este el primer reporte de vasculitis linfocítica en niños, y además se realiza una revisión de la literatura.

Role of streptococcal infection in the etiopathogenesis of pityriasis lichenoides chronica and the therapeutic efficacy of azithromycin: a randomized controlled trial.

The exact aetiology of pityriasis lichenoides chronica (PLC) remains unknown. While phototherapy is the most investigated therapeutic modality, azithromycin has been used scarcely. The aim of this study is to evaluate the therapeutic efficacy of azithromycin in the treatment of PLC compared to NB-UVB and evaluating the presence of streptococcal infection as a possible etiological factor in PLC patients. The study was designed as a randomised controlled trial. Twenty-four patients with PLC were randomly allocated into either azithromycin (n = 13, standard dose every 10 days) or NB-UVB (n = 11, thrice weekly) groups. End of study (EOS) was either complete clearance of lesions or a maximum of 8 weeks. Therapeutic efficacy was defined as percent reduction in lesions and was calculated for the rash as a whole, erythematous papules alone, and hypopigmented lesions alone and graded into complete, very-good, good, poor or no response. Anti-streptolysin O titre (ASOT), anti-deoxyribonuclease B titre (anti-DNaseB) and throat culture were evaluated at day 0. No significant difference existed between both groups as regards therapeutic efficacy. At EOS, NB-UVB achieved significantly more percent reduction in the extent of hypopigmented lesions and consequently in the rash as a whole (p = 0.001, p = 0.034, respectively). The extent of the rash as a whole was significantly less in the NB-UVB at EOS (p = 0.029, respectively). The effect of NB-UVB on hypopigmented lesions appeared early at week 4 of treatment. Only two patients, one from each group, relapsed during the 3 month follow-up. Evidence of recent streptococcal infection was present in 79% of the cases, mainly in the form of elevated ASOT (94.7%). It was significantly more encountered in young children (< 13 years) (p = 0.03) and was associated with more extent of erythematous papules and consequently with more extent of the rash as a whole (p = 0.05 and p = 0.01, respectively). It did not affect outcome of therapy at EOS. Azithromycin did not show more favorable response in patients with recent streptococcal infection. Therapeutic efficacy of azithromycin is comparable to NB-UVB in treatment of PLC; however, NB-UVB is superior in management of hypopigmented lesions. It is highly suggested that PLC could be a post streptococcal immune mediated disorder.Registration number: ClinicalTrials.gov, NCT03831269.

Diagnostic Value of Plasmacytoid Dendritic Cells in Differentiating Pityriasis Lichenoides et Varioliformis Acuta From Lymphomatoid Papulosis.

ABSTRACT: Pityriasis lichenoides et varioliformis acuta (PLEVA) and lymphomatoid papulosis (LyP) can often demonstrate clinical and histopathologic overlap. A recent study demonstrated significant plasmacytoid dendritic cell (pDC) recruitment in lesions of PLEVA, whereas another study reported minimal pDC recruitment in lesions of LyP. To confirm the possible diagnostic value of pDCs in differentiating PLEVA and LyP, we compared the presence and distribution of pDCs and myxovirus protein A (MxA) expression (an indirect assessment of pDC activity). In total, 19 cases of PLEVA (16 patients) and 14 cases of LyP (11 patients) were examined using immunohistochemical stains for anti-blood-derived dendritic cell antigen-2 and MxA. Individual semiquantitative scoring systems were used to assess the immunohistochemical results, and a Mann-Whitney test with a subsequent 2-tailed P test was performed for statistical analysis. No statistically significant difference in the number of pDCs in both groups was found. However, most PLEVA cases (84%) demonstrated intense and diffuse MxA expression, whereas LyP cases (71%) demonstrated weak patchy staining (P < 0.007). Our study suggests that although additional studies may be needed to determine whether pDCs are more relevant to the pathogenesis of PLEVA or LyP, pDC activity through MxA staining may play a role in differentiating PLEVA from LyP and may serve as a platform for additional studies.

Clinical characteristics and long-term outcome of 223 patients with mycosis fungoides at a single tertiary center in Korea: A 29-year review.

BACKGROUND: Data regarding Asian patients with mycosis fungoides (MF) are limited. OBJECTIVE: We aimed to investigate the clinical profile and long-term outcomes of patients with MF in Korea. METHODS: A retrospective review of 223 patients with MF who were followed up for more than 6 months or died of MF within 6 months of diagnosis was performed. RESULTS: Approximately 96.4% and 3.6% of the patients had an early stage and advanced stage, respectively. The mean age at diagnosis was 44.8 years. The mean duration of symptoms before diagnosis was 47.0 months. Various subtypes were noted, including mycosis fungoides palmaris et plantaris (21.5%), folliculotropic (8.5%), pityriasis lichenoides-like (6.7%), ichthyosiform (4.0%), lichenoid purpura-like (2.7%), and hypopigmented (2.2%) MF. Juvenile patients accounted for 16.6%. The higher the skin T stage, the poorer the response to treatment. The 10-year overall survival was 96.8% in early-stage patients and 25.0% in advanced-stage patients. General prognosis was favorable, while recurrence and subtype switching were seen in 29.4% and 2.7% of patients, respectively. LIMITATIONS: Our patients may not represent all Korean patients with MF. CONCLUSION: MF in Korea has a high proportion of variants, a younger age at onset, and favorable prognosis. A high index of suspicion and skin biopsy are needed for early diagnosis.

Hypopigmented lesions in pityriasis lichenoides chronica patients: Are they only post-inflammatory hypopigmentation?

BACKGROUND/OBJECTIVES: Pityriasis lichenoides chronica (PLC) lesions are reported to subside with post-inflammatory hypopigmentation (PIH); hence, the most widely perceived nature of hypopigmented macules in PLC is PIH. However, to the best of our knowledge, no studies describing histopathological findings in these lesions are reported in literature. The aim of this study is to evaluate the hypopigmented lesions encountered in PLC patients and to shed light on their histopathological features. METHODS: A cross-sectional observational study included twenty-one patients with PLC recruited in a period of twelve months. Clinical characteristics of each patient were collected. A skin biopsy from hypopigmented lesions whenever present was taken and assessed with routine haematoxylin and eosin stain. RESULTS: Seventeen patients (81%) were less than 13 years old. Most patients (85.7%) demonstrated diffuse distribution of lesions. Hypopigmented lesions were present on the face in 12 (57.14%) patients. Histopathologically, hypopigmented lesions showed features of post-inflammatory hypopigmentation in 19% of patients, residual PLC in 52.4% and active PLC 28.6% of patients. CONCLUSION: Hypopigmented lesions in PLC were noted mainly in younger ages, histopathologically they may show features of active or residual disease, beyond post-inflammatory hypopigmentation. Consequently active treatment for patients presenting predominantly with hypopigmented lesions could be required to control the disease.

Pityriasis lichenoides: a clinical and pathological case series of 49 patients with an emphasis on follow-up.

The classification of pityriasis lichenoides (PL) into pityriasis lichenoides et varioliformis acuta (PLEVA), PL chronica (PLC) and febrile ulceronecrotic Mucha-Habermann disease (FUMHD) is based on both clinical and chronological features. In this retrospective monocentric study, we aimed to investigate the relevance of the classification in routine practice. We enrolled 49 patients (25 female, 24 male; median age 41 years). The lesions were papular in 76% of patients, necrotic in 12% and mixed in 12%. We found three histological patterns: 'classic' (65%), 'lymphomatoid' (13%) and 'mild' (22%). The 'lymphomatoid' pattern was associated with necrotic presentation and the 'mild' pattern with papular lesions (P = 0.01). Among the 27 patients with follow-up, 18% had relapses and 44% had chronic disease. One patient had mycosis fungoides. Neither clinical nor histological findings were correlated with disease progression, and are a reflection of the intensity of epidermal injury rather than of the disease course. The term 'pityriasis lichenoides' should be preferred to the classic PLEVA/PLC/FUMHD classification.

Rhabdomyomatous mesenchymal hamartoma presenting as telangiectasia in a 57-year-old man.

Rhabdomyomatous mesenchymal hamartoma (RMH) is a rare congenital malformation of the dermis and subcutaneous tissue. Usually, RMH occurs in the midline of the face and neck region. We described a case of RMH presenting as telangiectasia in a 57-year-old man with a history of pityriasis lichenoides chronicus. Histopathological examination revealed a subepidermal haphazard proliferation of striated muscular tissue perpendicular to the epidermis. These bundles of striated muscular tissue were admixed with adnexal structures. The diagnosis was consistent with RMH. RMH is more common in the neonatal period or in young children, but we should consider it as part of a differential diagnosis in older adults as well.

Histopathologic features distinguishing secondary syphilis from its mimickers.

BACKGROUND: Syphilis is often misdiagnosed clinically, and biopsies might be required. OBJECTIVE: To determine histopathologic features that distinguish secondary syphilis from pityriasis lichenoides (PL), pityriasis rosea (PR), and early mycosis fungoides (MF). METHODS: Histopathologic features of 100 cases of syphilis, 110 cases of PL, 72 cases of PR, and 101 cases of MF were compared. RESULTS: Elongated rete ridges and interstitial inflammation favor syphilis over PL (likelihood ratios 3.44 and 2.72, respectively), but no feature reliably distinguishes between them. Secondary syphilis and PR can be distinguished by neutrophils in the stratum corneum, plasma cells, interface dermatitis with lymphocytes and vacuoles, and lymphocytes with ample cytoplasm. Plasma cells and lymphocytes with ample cytoplasm are rare in early MF and can be used as distinguishing features. CONCLUSIONS: Histopathologic features characteristic of syphilis can be seen in PL, PR, and early MF. Distinguishing syphilis from PL can be difficult histologically, and a high index of suspicion is required. Although elongation of rete and interstitial inflammation favor syphilis, plasma cells (historically considered a significant feature of syphilis) are often encountered in PL. Vacuolar interface dermatitis with a lymphocyte in every vacuole is considered characteristic of PL, but this feature appears to be more common in syphilis.

Pityriasis Lichenoides: A Large Histopathological Case Series With a Focus on Adnexotropism.

INTRODUCTION: Pityriasis lichenoides (PL) is an infrequent skin disorder. The clinical manifestations are usually specific enough for a reliable diagnosis, although the histopathological assessment of a biopsy is sometimes needed to differentiate between PL and a range of other diseases. The objectives of this study were to review cases of PL managed in our hospital, confirm the classical histopathological features of PL, and identify signs that may be of value in the diagnosis of PL. MATERIALS AND METHODS: All cases of PL assessed in our pathology department between January 2007 and December 2017 were retrieved, and all slides were reviewed. Cases were selected only if a diagnosis of PL was initially suggested by a dermatologist and then confirmed by the histopathological assessment. RESULTS: Seventy-one cases met the study criteria. The following features were almost always present: vacuolar changes or necrotic keratinocytes (100%), both superficial and deep lymphocytic infiltrates (99%), and the infiltration of lymphocytes into the adnexal epithelium (97%). The inflammatory cells were always small- to medium-sized lymphocytes. There were no eosinophilic infiltrates. Superficial perivascular and/or intraepidermal red blood cells were observed in 83% of cases. DISCUSSION: We highlighted the presence of a deep dermal lymphocytic infiltrate, with a "T-shaped" periadnexal arrangement along the full length of the follicular and sudoral epithelia. This might be a feature that enables the differentiation of PL from other diseases. Our findings also prompted a number of physiopathological hypotheses for PL. CONCLUSIONS: Our present results confirmed the classical histological aspects of PL and provided some useful new diagnostic features.

Lymphomatoid Papulosis and Other Lymphoma-Like Diseases.

Pityriasis lichenoides et varioliformis acuta and pityriasis lichenoides chronica are the 2 main subtypes of pityriasis lichenoides. They represent the acute and chronic forms of the disease; both may have clonal T cells. Several treatment modalities are used, but it has been difficult to determine efficacy because of the possibility of spontaneous remission. Cutaneous CD30+ lymphoproliferative disorders constitute many cutaneous T-cell lymphomas and comprise lymphomatoid papulosis and primary cutaneous anaplastic large cell lymphoma (ALCL). Both have an excellent prognosis. Lymphomatoid papulosis often only requires observation or treatment of symptoms. First-line therapies for primary cutaneous ALCL are surgical excision or radiotherapy.

PUVA-induced pityriasis lichenoides chronica-like papular lesions in patients with mycosis fungoides: a clinical, histopathological and immunohistochemical study.

Mycosis fungoides (MF) is the most common form of cutaneous T cell lymphoma (CTCL) with many clinical variants including papular and pityriasis lichenoides chronica (PLC)-like variants. During psoralen and ultraviolet A (PUVA) treatment of MF, PLC-like papular lesions were observed to appear. The exact nature of these lesions is not fully understood. This work aimed to study PLC-like papular lesions arising in MF patients receiving PUVA therapy clinically, histopathologically and immunohistochemically (using monoclonal antibodies against CD4 and CD8) and to compare them with lesions in classic PLC patients. Fifteen MF patients with PLC-like papular lesions arising during PUVA treatment were included and 15 patients with classic PLC served as controls. While the extent of these lesions significantly correlated with their duration (p < 0.05), it showed no significant correlation with the TNMB stage of MF, number of phototherapy sessions or cumulative UVA dose at which they started to appear. The response status of MF to PUVA did not affect their development. Compared to classic PLC, these lesions showed significantly more acute onset (p = 0.003). None of these lesions showed histopathological features essential to diagnose papular/PLC-like MF and no significant difference existed with regard to their histopathological and CD4/CD8 phenotypic features compared to classic PLC. Papular lesions mimicking PLC in MF patients receiving PUVA mostly represent an upgrading reaction with possible good prognostic implication.

An Atypical Presentation of PLEVA: Case Report and Review of the Literature

Pityriasis lichenoides et varioliformis acuta (PLEVA) is a rare, self-limited, cutaneous disorder of unknown etiology. Clinically, PLEVA is characterized by the sudden onset of scaly, erythematous macules and papules localized to the trunk and proximal extremities. We report the case of a patient who presented with multiple erythematous papules and plaques on the palms, forearms, and dorsal feet. J Drugs Dermatol. 2019;18(7):690-691.