暂无摘要。

暂无摘要。

Febrile ulceronecrotic Mucha-Habermann disease is a rare and severe variant of pityriasis lichenoides, characterized by sudden onset of generalized ulceronecrotic papules that rapidly coalesce into ulcers associated with high fever. Systemic manifestations such as intravascular disseminated coagulation and pulmonary, cardiac, gastrointestinal, and central nervous system involvement are common. Treatment is based on oral corticosteroids, immunosuppressive drugs such as methotrexate, and general supportive treatment. The present case describes a stepwise approach to a patient with Mucha-Habermann disease with insufficient response to methotrexate.

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.

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.

BACKGROUND: Psoriasis is an inflammatory skin disease driven by upregulation of cytokines in the Th17 pathway, including interleukin-36 (IL-36). Previous studies have highlighted the utility of IL-36 immunostaining for psoriasis compared to spongiotic dermatitis and other psoriasiform dermatoses; however, no study has examined the role of IL-36 staining in distinguishing psoriasis from pityriasis rosea (PR) and pityriasis lichenoides (PL), known histologic mimickers of psoriasis.
METHODS: We compared the immunostaining pattern of IL-36 for 21 PR cases, 22 PL cases, and 10 psoriasis cases. We graded the immunostaining as 0, negative; 1, focal weak; 2, diffuse weak; 3, focal, strong; or 4, diffuse strong. We further categorized stains as negative (0-2 score) or positive (3-4 score) and utilized Fisher\'s exact test to compare the immunostaining pattern of these entities.
RESULTS: All psoriasis specimens were positive for IL-36, whereas all PR specimens were negative (p = 0.00000002). Twenty PL specimens were negative (p = 0.000001). Nine of 10 pityriasis lichenoides et varioliformis acuta cases were negative (p = 0.00012), and 11 of 12 cases of pityriasis lichenoides chronica were negative (p = 0.00003).
CONCLUSIONS: Our findings highlight the potential role of IL-36 immunostaining in distinguishing psoriasis from other psoriasiform dermatoses, including PR and PL.

OBJECTIVE: This study aims to evaluate the characteristics and treatment response of patients with pityriasis lichenoides seen in the last 43 years in a pediatric dermatology service.
METHODS: This was a retrospective, analytical, longitudinal study of patients under 15 years of age. The medical records were reviewed and data were presented as frequencies, means and variances. Student\'s t-test, Mann-Whitney test, Fisher\'s exact test, Pearson/Yates chi-square test and multivariate logistic regression model were used, with p < 0.05 considered.
RESULTS: 41 patients were included, 32 (78.0%) with pityriasis lichenoides chronica (PLC), five (12.2%) with pityriasis lichenoides et varioliformis acuta (PLEVA) and four (9.8%) with clinical PLC without biopsy. The age range of school children and adolescents was 19 (46.3%) and 13 (31.7%) respectively and 27 (65.8%) were male. Two peaks of the highest frequency were observed between 2004 and 2006 (10 patients - 24.4%) and another between 2019 and 2021 (6 patients - 14.7%). There was remission in 71.9% (n = 23), with 56.6% (n = 17) of those who used antibiotic therapy and 80% (n = 4) of those who had phototherapy. The chance of remission was 13 times greater in patients with disease onset after 5 years of age.
CONCLUSIONS: The clinical form most commonly found was PLC mainly in school children and adolescents. The frequency peaks coincided with infectious outbreaks. The remission rate was satisfactory with antibiotic therapy, but higher with phototherapy. Remission was greater in patients with disease onset after 5 years of age.

BACKGROUND: Pityriasis lichenoides chronica is the chronic end of the spectrum of pityriasis lichenoides which have several forms of papulosuamous conditions. Several treatments obtained complete clearance of the condition including phototherapy and specifically narrow band ultraviolet B. The Excimer light 308 is a monochromatic light that acts within the ultraviolet B wavelength and used as a targeted phototherapy in several skin conditions.
METHODS: Thirty-four patients with histopathologically diagnosed pityriasis lichenoides chronica underwent treatment with biweekly sessions of excimer light 308 nm. Treatment continued until complete clearance was obtained or to a maximum of 48 sessions (24 weeks).
RESULTS: Thirty-one patients obtained complete clearance with no recurrence till the end of the study period, two patients had partial response and only one patient showed poor response to treatment.
CONCLUSIONS: Excimer light can be a safe and effective treatment of pityriasis lichinoides chronica in different ages and genders.

BACKGROUND: Lymphomatoid papulosis (LyP) is a rare cutaneous T-cell lymphoproliferative disorder. Comprehensive data on LyP in the paediatric population are scarce.
OBJECTIVE: To characterize the epidemiological, clinical, histopathological and prognostic features of paediatric LyP.
METHODS: This was a retrospective multicentre international cohort study that included 87 children and adolescents with LyP diagnosed between 1998 and 2022. Patients aged ≤ 18 years at disease onset were included. LyP diagnosis was made in each centre, based on clinicopathological correlation.
RESULTS: Eighty-seven patients from 12 centres were included. Mean age at disease onset was 7.0 years (range 3 months-18 years) with a male to female ratio of 2 : 1. Mean time between the onset of the first cutaneous lesions and diagnosis was 1.3 years (range 0-14). Initial misdiagnosis concerned 26% of patients. LyP was most often misdiagnosed as pityriasis lichenoides et varioliformis acuta, insect bites or mollusca contagiosa. Erythematous papules or papulonodules were the most frequent clinical presentation. Pruritus was specifically mentioned in 21% of patients. The main histological subtype was type A in 55% of cases. When analysed, monoclonal T-cell receptor rearrangement was found in 77% of skin biopsies. The overall survival rate was 100%, with follow-up at 5 years available for 33 patients and at 15 years for 8 patients. Associated haematological malignancy (HM) occurred in 10% of cases (n = 7/73), including four patients with mycosis fungoides, one with primary cutaneous anaplastic large cell lymphoma (ALCL), one with systemic ALCL and one with acute myeloid leukaemia. If we compared incidence rates of cancer with the world population aged 0-19 years from 2001 to 2010, we estimated a significantly higher risk of associated malignancy in general, occurring before the age of 19 years (incidence rate ratio 87.49, 95% confidence interval 86.01-88.99).
CONCLUSIONS: We report epidemiological data from a large international cohort of children and adolescents with LyP. Overall, the disease prognosis is good, with excellent survival rates for all patients. Owing to an increased risk of associated HM, long-term follow-up should be recommended for patients with LyP.
Lymphomatoid papulosis is a very rare skin condition caused by an abnormal increase in white blood cells (called ‘lymphocytes’) in the skin. The condition rarely affects children, so most of the scientific data published about this disease focuses on adults. This study involved 12 academic dermatology centres in Europe, the Middle East and North America, and gathered data from about 87 children who presented with symptoms of lymphomatoid papulosis before the age of 19 years. The aim of this study was to better describe this disease in the paediatric population and discuss its treatment options and evolution. We found that the presentation of the disease in children is roughly the same as in adults. Safe and effective treatment options exist. The disease is not life threatening, but it requires investigation by a dermatologist, both to make a careful diagnosis and to monitor it as sometimes associated cancers that originate from blood cells can occur, mostly on the skin.

UNASSIGNED: Mucha-Habermann disease (MHD) is an inflammatory skin disease characterized by polymorphous eruptions of erythematous, necrotic macules that have been reported for similarities to cutaneous T-cell lymphoma. Febrile ulceronecrotic MHD (FUMHD) represents a severe variant of MHD, marked by ulcers, hemorrhagic bullae, and systemic symptoms. Herein, we report a case of a severely atypical lymphomatoid expression of FUMHD associated with hemophagocytic lymphohistiocytosis (HLH). A previously healthy 21-year-old woman was admitted to the hospital with a rapidly progressive necrotic papular rash. Physical examination revealed right orbital swelling, bilateral hemorrhagic auricular bullae, and multiple ulcerative purpuric papulonodules on the trunk, face, and extremities. Biopsy indicated a dermal and subcutaneous infiltrate of atypical CD8 + lymphocytes with loss of CD5 and reduction in CD7 expression, along with features of lymphomatoid vasculitis. A diagnosis of a severely atypical lymphomatoid expression of FUMHD was made. The patient also met 7 of 9 HLH-2004 criteria, leading to a diagnosis of HLH. Positron emission tomography/computed tomography, flow cytometry, and rheumatologic workup were unremarkable. Treatment with an eight-week course of etoposide and dexamethasone for HLH led to rapid clinical improvement. Over time, her skin lesions regressed and eventually scabbed over to leave hyperpigmented scars, confirming the diagnosis of MHD. She has remained stable, off therapy for 4 years. Although potentially fatal, FUMHD often exhibits favorable outcomes and may resolve without recurrence, as in our patient. FUMHD should be considered in the differential diagnosis for patients presenting with cutaneous CD8 + necrotizing angiocentric lymphoproliferative disease complicated by HLH.