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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., (Copyright: © 2023 Permanyer.)

Background and objectives : Pytiriasis alba (PA) is a common skin disorder which affects 80% of children between six and 16 years. The etiology of PA is unclear, but hypo-pigmented patches in photo-exposed zones characterize the disease. Because the high ultraviolet exposition of the skin promotes an acute inflammatory response and an increase of oxidative stress (OS), this study aimed to evaluate the expression levels of inflammatory and OS-related genes in skin biopsies, and their association with PA. Materials and Methods : A cross-sectional study was carried out. Skin biopsies of the lesion sites and healthy skin (controls) from 16 children with PA were evaluated. The tissue expression of IL-4, IL-6, IL-17A, TNFα, INFγ, IL-1β, SOD1, and HMOX1 was analyzed by qRT-PCR, using SYBR Green and glyceraldehyde-3-phosphate dehydrogenase gene as the endogenous control. Results : There were differences in the ΔCq values of HMOX1, SOD1, IL-6, and IFNγ between tissue with lesions and healthy skin ( p < 0.05). Compared with healthy skin, IL-6, IFNγ, HMOX1, and SOD1 were predominantly under-expressed in the lesion sites. However, 25% of skin biopsies with lesions showed over-expression of these four genes. Positive correlations between the expression of IL-6 and HMOX1, SOD1, and IFNγ ( p < 0.05) were also observed. Conclusions : Our results suggest the presence of molecular stages of PA, defined according to the over-expression (first stage) or under-expression (second stage) of the HMOX1, SOD1, IL-6, and IFNγ genes in abnormal skin tissue. These findings may have implications for the selection of treatment for PA-related lesions.

Pityriasis rotunda disorder of keratinization clinically described as persistent, large, sharply defined circular patches of ichthyosiform scaling with no inflammatory changes. Patients with pityriasis rotunda may be classified into one of two groups, which are based on ethnicity, number of lesions, family history, and association with systemic diseases. A 45-year-old woman presented with asymptomatic, sharply-demarcated, round, scaly, hyperpigmented lesions on her leg that had been present for several years. Our patient did not have systemic disease or malignancy and so does not fit into groups already described.

Background: Pityriasis alba affects 1% of the world population and about 9.9% of the children in Brazil. However, its etiology remains uncertain., Objective: The objective of the present study was to evaluate the immunoexpression of factor XIIIa in dermal dendrocytes of skin lesions of pityriasis alba., Method: Twenty patients with pityriasis alba and 20 patients with atopic dermatitis underwent biopsy. The dermal dendrocytes marked by factor XIIIa were counted by means of immunohistochemical analysis., Results: The mean amount of dermal dendrocytes found in the patients with pityriasis alba was 2, whereas in the patients with atopic dermatitis it was 4, with a statistically significant difference between them. A cutoff point of 3 cells/square inch was established to differentiate pityriasis alba from atopic dermatitis, with 80% sensibility and 90% specificity., Conclusion: We believe that pityriasis alba and atopic dermatitis should be considered different clinical forms within the spectrum of atopic disease, in which sun radiation plays an important role by modulating the progression of the disease.

We present a 65-year-old man with Darier disease with pityriasis amiantacea on the scalp, alopecia, and congenital facial nerve palsy.

Acquired hypopigmentary disorders comprise a significant group of disorders that affect Indians and Asians. The pigment disturbance in darker skin individuals can be very distressing to the patient and the family. These disorders cover a wide array of pathologies including infections, autoimmune processes, lymphoproliferative disorders, and sclerosing diseases. Histological diagnosis is particularly important because treatments for these diseases are varied and specific. This review will focus on histopathological diagnosis based on clinicopathological correlation for commonly encountered disorders such as leprosy, vitiligo, lichen sclerosus, pityriasis alba (PA), and pityriasis versicolor (PV). Atypical or uncommon clinical presentation of classic diseases such as hypopigmented mycosis fungoides (HMF) and hypopigmented sarcoidosis are also included.

Despite an increasing knowledge of dandruff and seborrheic dermatitis (D/SD), the pathophysiological understanding is still incomplete but suggests a role of Malassezia yeasts in triggering inflammatory and hyper-proliferative epidermal responses. The objective of this report is to review published literature from in vivo studies of D/SD populations to provide a more complete description of overall scalp health. New biomolecular capabilities establish a depth of pathophysiological understanding not previously achievable with traditional means of investigation. Biomarkers representing inflammation, hyper-proliferation and barrier function are all perturbed by the D/SD condition and robustly respond to therapeutic resolution. These biomarkers can be sampled noninvasively, enabling their use in routine clinical evaluations as either surrogate endpoints or complementary ones to classical signs/symptoms to broaden the etiological learning.

Pityriasis Amiantacea, also known as pseudotinea amiantacea, is a clinical syndrome which affects the scalp, having a reaction pattern reported to occur in several inflammatory dermatoses. The authors seek to establish the correlation between its clinical, dermoscopic and light microscopy features through the analysis of scale- encrusted hair tufts submitted to histological processing.

A 42-year-old man presented with asymptomatic, sharply-demarcated, round, scaly lesions on his forearms that had been present for several months. A skin biopsy specimen was consistent with pityriasis rotunda. Pityriasis rotunda is a disorder of keratinization, which is thought to be a form of acquired ichthyosis, a delayed presentation of congenital ichthyosis, or a cutaneous manifestation of systemic disease. Patients with pityriasis rotunda may be classified into one of two groups, which are based on ethnicity, number of lesions, family history, and association with systemic diseases. Treatment is challenging, but the use of lactic acid lotion and oral vitamin A has shown some promise.

Febrile ulceronecrotic Mucha-Habermann disease is a severe variant of pityriasis lichenoides et varioliformis acuta characterized by the sudden onset of ulceronecrotic skin lesions and associated with high fever and systemic symptoms. We report here a case of a 20-year-old woman in whom the disease started as pityriasis lichenoides et varioliformis acuta and evolved to febrile ulceronecrotic Mucha-Habermann disease. Almost 90% of the body surface was involved, together with high fever and malaise. Steroids alone proved to be an insufficient therapeutic procedure. The remission achieved was attributed to the use of methotrexate. To our knowledge, only 39 cases of febrile ulceronecrotic Mucha-Habermann disease have been reported in the literature to date.

Recently, we identified a particular T-cell subset in the peripheral blood of normal individuals that lack CD7 expression. In this study we determined the portion of CD7- T cells in the peripheral blood and skin of patients with various inflammatory skin diseases. We found that skin-infiltrating lymphocytes isolated from different benign and malignant skin lesions (n = 20) contain a high portion of CD7- helper T cells, whereas the number of CD7- T cells in the peripheral blood was not altered compared to healthy controls. Cell activation in vitro did not induce CD7 expression in negative T cells but increased CD7 expression in CD7-positive cells. Thus, lack of CD7 expression seems to be a stable characteristic in a major subset of skin-infiltrating lymphocytes. During long-term culture of CD7- helper T-cell clones derived from a psoriasis skin lesion, no phenotypic change in the CD7 phenotype could be monitored by sequential flow-cytometric analyses. No CD7 mRNA could be detected by Northern blot analysis, indicating transcriptional regulation of CD7 expression. The results show that CD7- T cells accumulate in certain inflammatory skin lesions without alteration of the circulating CD7- population. These cells may be identical to or derived from CD7- T cells of the peripheral blood.

The scanning electron microscope has been used to examine scales taken from the scalp of 3 patients with pityriasis amiantacea alone, 3 psoriatic patients with pityriasis amiantacea and one patient with both atopic dermatitis and pityriasis amiantacea. Samples from 2 patients were additionally studied by different fixation techniques and in the frozen hydrated state, but no cementing of the scales could be observed. There was no evidence of an infective agent.

Three patients with pityriasis alba whose lesions were confined to the knees only are reported. Such cases can be misdiagnosed as psoriasis. The key to the correct diagnosis lies in the physician's awareness of the existence of this variant of pityriasis alba.

Lymphomatoid papulosis (LyP) and pityriasis lichenoides et varioliformis acuta (PLEVA) are benign self-healing cutaneous eruptions that may be clinically and histologically similar. However LyP has a 5% to 20% risk of associated lymphoid malignancy, whereas PLEVA does not. To determine whether the immunophenotype of lymphoid cells is useful in the distinction of these two disorders, the pattern of expression of lymphoid cell lineage and activation antigens in nine cases of LyP and seven cases of PLEVA were compared. In all cases of LyP most larger cells expressed the activation antigen Ki-1 (CD30) and lacked expression of the T-cell antigen CD7 and at least one other T-cell antigen (CD2, CD3, CD5). In contrast, CD30-antigen expression was rare or absent in PLEVA, CD3- and CD7-antigen expression was found in all cases, and diminished expression of T-cell antigens (CD2 and CD5) was seen in only one case. Diffuse expression of HLA-DR antigen by epidermal keratinocytes was found in a greater proportion of PLEVA cases (6 of 7) than LyP cases (3 of 6). In addition, CD8+ cells predominated at the dermal/epidermal junction in 3 of 6 cases of PLEVA but in only 1 of 7 cases of LyP. We conclude that LyP and PLEVA can be distinguished immunohistochemically in most, if not all, cases. Furthermore these results suggest that LyP and PLEVA are separate disorders, thus accounting for their variable prognoses.

Dendritic cells bearing Langerhans cell (OKT6+) or interdigitating cell (RFD1+) immunophenotype may be regularly detected within the dermis of chronic skin diseases characterized by a lymphohistiocytic (lymphoreticular) infiltrate. These 2 subsets of antigen-presenting cells within the dermis of lesions of exacerbating chronic plaque psoriasis, exacerbating nummular dermatitis (discoid eczema), atopic dermatitis, allergic contact dermatitis, pityriasis rosea, lichen ruber planus, and cutaneous lupus erythematosus were quantified using computer-assisted morphometry. The mean dendrite length per dermal dendritic cell was significantly higher for RFD1 than for OKT6 (74.4 +/- 0.98 microns vs 70.0 +/- 1.26 microns: p = 0.0023). The mean dendrite length per dermal dendritic cell was remarkably constant for each marker in the various diagnostic categories studied. Disease-specific patterns of total dendrite length and number (expressed per 100 infiltrating mononuclear cells) of these 2 dendritic cell types within the subepidermal infiltrates were obtained. Pityriasis rosea was characterized by its unique high percentage of OKT6+ Langerhans cells. Atopic dermatitis and psoriasis had relatively high percentages of both RFD1+ interdigitating cells and OKT6+ Langerhans cells. Nummular dermatitis had an intermediate number and total dendrite length for OKT6, but was relatively low in RFD1+ cells. Allergic contact dermatitis, lichen planus, and lupus erythematosus had low numbers and dendrite lengths for both dendritic cell subsets. It is suggested that pityriasis rosea is characterized by an abnormal migration pattern of Langerhans cells. Psoriasis and atopic dermatitis may be examples of diseases in which skin-localized antigen-presenting and T-cell-inducing events are continuously taking place. The other diseases may reflect inflammatory processes in which local antigen presentation is less relevant to the tissue reaction.

Unique cytolytic degeneration of keratinocytes adjacent to Langerhans cells was observed in five cases of pityriasis rosea (Gilbert). In the cytolytic area, the normal keratinocyte structures were absent except for free ribosomes. In addition, a similar cytolytic part of a keratinocyte was enveloped by the elongated dendrites of the Langerhans cell and was detected within its cytoplasm. The significance of these findings is discussed with respect to anticytoplasmic antibodies in the sera of patients with pityriasis rosea.

Patients with the skin disorder pityriasis lichenoides et varioliformis acuta (PLEVA) develop recurrent, self-healing papulonecrotic lesions that contain infiltrates of cytologically and antigenically normal T lymphocytes. DNA extracted from the lesions of 3 patients with PLEVA was analyzed for rearrangement of beta-T-cell receptor genes for the purpose of assessing the clonality of T lymphocytes within the tissues of this disease. Lesions from all 3 cases showed clonal gene rearrangements. In each of 2 cases from which two separate lesions were biopsied, identical rearrangements were found in specimens from both sites. DNA from a variety of inflammatory lesions obtained from patients with other types of skin diseases failed to show detectable rearrangements of beta-T-cell receptor genes. These results suggest that PLEVA represents a T-cell lymphoproliferative process, rather than an inflammatory disorder, as had been previously thought.

Histiocytic medullary reticulosis (HMR) is a rare, progressive, fatal reticuleondothelial proliferative disorder. It was diagnosed in a 10-year-old boy who had pityriasis lichenoides et varioliformis acuta of Mucha-Haberman which was controlled by dapsone for 2 years. One month after cessation of dapsone therapy, cutaneous tumors associated with fever, lymphadenopathy, and hepatosplenomegaly developed. Tissue biopsy specimens of skin, liver, spleen, lymph nodes, and a bone marrow aspirate demonstrated histiocytic erythrophagocytosis and atypical histiocytosis compatible with HMR. A rapidly progressing, fatal course followed despite intensive chemotherapy.

Pityriasis rosea is a skin disease which is obscure in its etiology and pathogenesis. We studied its immunopathology by immunophenotyping the inflammatory cells in situ using monoclonal antibodies that define leukocyte subsets. Findings as to T-cells and their major subsets did not reveal disease-specific data. Monocytes stained only rarely. Neither natural killer cells, B-cells nor plasma cells were ever found. An unexpected finding was the presence within the infiltrates and rarely within the epidermis of cells having the immunophenotype of interdigitating cells (RFD1+). Intense and dendritic staining with anti-T6 and anti-HLA-DR indicated Langerhans cells to be present in the dermal infiltrates, in between these infiltrates in the papillary dermis, and focally within the parakeratotic horny layer. This Langerhans' cell pattern provides evidence for dermal Langerhans cell compartmentalization and transepidermal Langerhans' cell elimination. Such a distribution indicates a change in Langerhans' cell migration processes in pityriasis rosea pathogenesis.

The affected skin of pityriasis alba showed functional defects in both hygroscopicity and water-holding capacity detectable by water sorption-desorption test. Furthermore using skin surface biopsy technique in 5 patients, we noted that the mean area of corneocyte obtained from the affected skin of pityriasis alba was smaller and that the surface of that area showed a more prominent villous pattern than the adjacent normal skin in scanning electron microscopical observation. In this study we demonstrated the abnormalities of the horny layer in pityriasis alba, which suggest that the condition is similar to a dermatitic change and that its hypopigmentation may be due to postinflammatory mechanisms.