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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.

Objectives: 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.

Objectives: 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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Pityriasis lichenoides (PL) is defined as a skin disorder with an unclear etiology that mostly affects children and adolescents. Pityriasis lichenoides chronica (PLC) is the chronic form, characterized by recurrent collections of scaly erythematous papules that spontaneously disappear over weeks, months or years. Here we report a case of a male, who presented with the main complaint of partially brownish red nodules that were scaly and brown-black spots, without itching, all over the body, present over the past 2 years. The nodules extend to the stomach area, both arms, both legs and finally to almost all parts of the body. The patient was treated with 500 mg erythromycin tablets four times a day and 0.25% desoximethasone ointment which was applied twice a day. Pityriasis lichenoides chronica is a skin condition with unknown etiology that appears as scaly erythematous papules that are easily detached, recurrent and can disappear spontaneously for several weeks, months to years. A gold standard therapy for PL is not yet available and is still a future challenge. [ABSTRACT FROM AUTHOR]

Purpose of reviewPityriasis lichenoides (PL) is a spectrum of dermatological conditions involving polymorphous lesions. Natural history of the condition ranges from acute to chronic. Cases of PL following SARS-CoV-2 infection/vaccination have been reported, but not yet comprehensively reviewed. Hence, the objective of this article is to review and summarize cases of PL following SARS-CoV-2 infection/vaccination in order to guide clinicians in its diagnosis and management.Recent findingsPubMed, Embase, and Web of Science were searched for relevant articles. Thirteen articles, consisting of 14 cases of PL following SARS-CoV-2 infection/vaccination, were identified. Males represented 64.3% of cases, and the average age of those affected was 41.4 years. The majority of cases (N = 9, 64.3%) were following SARS-CoV-2 vaccination, the most commonly implicated being Pfizer-BioNTech (n = 8/10, 80%), while four (28.6) followed infection. The overall latency period ranged from 5 days to 1 month. Treatments varied greatly. However, at the time of follow-up, 12/14 patients (85.7%) had either marked improvement or complete resolution of lesions.SummaryThis review cannot determine causality. However, a temporal association was observed with the case reports, and one case of PL followed SARS-CoV-2 infection and recurred with subsequent vaccination, suggesting an association. Nevertheless, risk of developing PL following SARS-CoV-2 infection/vaccination is likely extremely low. There is also the possibility these cases are purely coincidental. Still, clinicians should be aware of this possible etiology when diagnosing a new or exacerbated case of PL. Finally, given that the majority of patients had marked improvement or complete resolution of lesions at the time of follow-up, clinicians should provide reassurance to their affected patients.

Introduction: 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. Conclusion: Excimer light can be a safe and effective treatment of pityriasis lichinoides chronica in different ages and genders. [ABSTRACT FROM AUTHOR]

Introduction: Pityriasis lichenoides (PL) is a papulosquamous disease affecting both children and adults, for which narrowband‐UVB (NB‐UVB) phototherapy is regarded as a commonly used treatment option. The aim of this study was to investigate the efficacy of NB‐UVB phototherapy in the management of PL and to compare response rates in pediatric and adult age groups. Materials and methods: This observational, retrospective study included 20 PL patients (12 pityriasis lichenoides chronica; PLC, 8 pityriasis lichenoides et varioliformis acuta; PLEVA) who failed to respond to other treatment modalities. The data for this study were collected retrospectively from patient follow‐up forms in the phototherapy unit. Results: A complete response (CR) was obtained in all pediatric patients with PL, while 53.8% of adult patients had achieved CR. The mean cumulative dose required to achieve the CR was higher in pediatric patients than adult patients with PL (p <.05). The CR was achieved in 6 (75%) of 8 PLEVA patients, while 8 (66.7%) of 12 PLC patients had reached to CR. The mean number of exposures for patients with PLC to achieve a CR was higher than patients with PLEVA (p <.05). Erythema was the most common adverse effect during phototherapy particularly in 5 (35.7%) of the patients with PL who had achieved CR. Conclusions: NB‐UVB is an effective and well‐tolerated treatment option for PL especially in diffuse types. A higher response can be obtained in children with higher cumulative dose. Patients with PLC may require more exposures for CR than patients with PLEVA. [ABSTRACT FROM AUTHOR]

BACKGROUND: Pityriasis lichenoides is a rare, acquired skin disorder of unknown etiopathogenesis. Pityriasis lichenoides et varioliformis acuta is one of its forms of presentation and is clinically characterized by polymorphous lesions usually covered by hemorrhagic crusts with autolimited tendency, which may leave varioliform scars and residual hypo- or hyperpigmented macules. Diagnosis is clinical and is confirmed by histopathology, where confluent parakeratosis, necrotic keratinocytes and superficial and deep lymphohistiocytic inflammatory infiltrate can be observed. Regarding treatment there is no consensus, but tetracyclines, cyclosporine, methotrexate and phototherapy are described. CLINICAL CASE: A 15-year-old female patient with diagnosis of pityriasis lichenoides et varioliformis acuta, who presented relieve of the lesions after one month of management with doxycycline.CONCLUSIONS: Pityriasis lichenoides et varioliformis acuta is an uncommon dermatosis and few cases are reported in the literature. There is limited information on the theories of its etiopathogenesis and therapeutic options, which represents a challenge for the dermatologist. This case is striking given the significant improvement in a shorter time than established in the literature and with a tetracycline not frequently used in the reported cases. [ABSTRACT FROM AUTHOR]

Background: Pityriasis lichenoides is an uncommon papulosquamous disorder of an unknown etiology. The clinical spectrum consists of an acute ulcerative variant, pityriasis lichenoides et varioliformis acuta (PLEVA), and a chronic, non-ulcerative variant, pityriasis lichenoides chronica (PLC). A third, much more rare and aggressive form, febrile ulceronecrotic Mucha– Habermann disease (FUMHD), also occurs. Pityriasis Lichenoides is often benign, with a chronic course and with eventual spontaneous resolution over months to years. Objectives: The current study aims to evaluate the pityriasis lichenoides among patients attending Al-Sader medical city, Najaf, in the last five years, clinically and histologically. Patients and method: This is a case series performed retrospectively over the period from January 2017 through November 2021, in Najaf. Sixteen patients with clinical and histological PL were evaluated according to their medical records and online archives. A histopathological revision of their paraffin-embedded sections was also performed and statistically analyzed. Results: Sixteen patients with pityriasis lichenoides were evaluated; PLC was more common than PLEVA (14:2). PL mainly affects people in the second decade of life (37.5%). The age at the time of diagnosis ranged from 5 to 41 years, with a mean ±SD of 20.1± 9.9 years, which was higher for PLC (21.4±9.7) years than for PLEVA (11±7) years. Females outnumber males in PLC (9:5) as the only two reported cases of PLEVA were males. The skin phototype III was double that of type IV (11:5). More urban patients than rural patients were presented. The cases peak was in 2020 (31.25%), followed by 2021 (18.75). However, the clinical and histopathological features were classic and comparable to the published literature. Conclusion: PL is a disease predominant among young adults; more females were affected by PLC, while males were predominantly affected by PLEVA. More patients, who were more urban than rural, with skin phototype III were affected. [ABSTRACT FROM AUTHOR]

Cherrin Pomsoong, Poonkiat Suchonwanit, Kumutnart Chanprapaph, Ploysyne Rattanakaemakorn, Suthinee Rutnin Division of Dermatology, Department of Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, ThailandCorrespondence: Suthinee Rutnin, Division of Dermatology, Department of Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, 270 Rama VI Road, Ratchathewi, Bangkok, Thailand, 10400, Tel +66-2-2011141, Fax +66-2-201-1211, Email suthinee.rutnin@gmail.comAbstract: Pityriasis lichenoides et varioliformis acuta (PLEVA) and lymphomatoid papulosis (LyP) are uncommon inflammatory skin disorders that occasionally share clinicopathological features. Differentiating between the two entities remains problematic, and a definitive diagnosis usually requires multi-step investigations, which is an enormous challenge to physicians. We hereby report a rare case of a 22-year-old female patient diagnosed with PLEVA who later developed LyP type F, a new histological variant of LyP. Our report highlights that long-term follow-up is essential to determine associated hematologic malignancies, particularly in cases with recalcitrant or progressive cutaneous lesions of PLEVA and/or LyP.Keywords: chronic inflammatory skin disease, CD30 positive lymphoproliferative disorders, immunohistochemistry, mycosis fungoides, pityriasis lichenoides, cutaneous lymphoma

Pityriasis lichenoides is an acute and/or chronic skin disease associated with recurrent erythematous papules that self-resolve. While its etiology is unknown, preceding viral infection may play a role. We present an atypical case of a 40-year-old woman with pityriasis lichenoides et varioliformis acuta as a complication of a COVID-19 infection.

Background: Pityriasis lichenoides is an uncommon papulosquamous disorder of an unknown etiology. The clinical spectrum consists of an acute ulcerative variant, pityriasis lichenoides et varioliformis acuta (PLEVA), and a chronic, non-ulcerative variant, pityriasis lichenoides chronica (PLC). A third, much more rare and aggressive form, febrile ulceronecrotic Mucha–Habermann disease (FUMHD), also occurs. Pityriasis Lichenoides is often benign, with a chronic course and with eventual spontaneous resolution over months to years. Objectives: The current study aims to evaluate the pityriasis lichenoides among patients attending Al-Sader medical city, Najaf, in the last five years, clinically and histologically. Patients and method: This is a case series performed retrospectively over the period from January 2017 through November 2021, in Najaf. Sixteen patients with clinical and histological PL were evaluated according to their medical records and online archives. A histopathological revision of their paraffin-embedded sections was also performed and statistically analyzed. Results: Sixteen patients with pityriasis lichenoides were evaluated; PLC was more common than PLEVA (14:2). PL mainly affects people in the second decade of life (37.5%). The age at the time of diagnosis ranged from 5 to 41 years, with a mean ±SD of 20.1± 9.9 years, which was higher for PLC (21.4±9.7) years than for PLEVA (11±7) years. Females outnumber males in PLC (9:5) as the only two reported cases of PLEVA were males. The skin phototype III was double that of type IV (11:5). More urban patients than rural patients were presented. The cases peak was in 2020 (31.25%), followed by 2021 (18.75). However, the clinical and histopathological features were classic and comparable to the published literature. Conclusion: PL is a disease predominant among young adults; more females were affected by PLC, while males were predominantly affected by PLEVA. More patients, who were more urban than rural, with skin phototype III were affected.

Mycosis fungoides (MF) is the most common subtype of primary cutaneous T cell lymphomas, whereas pityriasis lichenoides chronica (PLC) is a chronic inflammatory skin disorder. The inflammasome is a part of the natural immune system which has a multimeric structure consisting of the receptor, adaptor and effector protein that show specificity for various ligands or activators. After the activation of the inflammasome complex, caspase 1 becomes activated which subsequently triggers interleukin-18 (IL-18) and interleukin-1β (IL-1β) production. In our study we aimed to examine the roles of nucleotide-binding oligomerization domain-like receptor containing pyrin domain 1 (NLRP1) and nucleotide-binding oligomerization domain-like receptor containing pyrin domain (NLRP3) inflammasomes in the etiopathogeneses of PLC and MF. NLRP1, NLRP3, caspase 1, IL-18 and IL-1β levels were examined and compared immunohistochemically in the skin biopsies belonging to 16 control patients; 16 PLC cases, 12 cases with stage 1 MF and 12 cases with other stages of MF (stage 2–4). In the paired comparisons of NLRP1, stage 2–4 MF group and PLC group were shown to have increased levels of NLRP1 expression compared to the control group. IL-1β was also expressed at statistically significantly higher levels in each of the stage 1 MF, stage 2–4 MF and PLC groups compared to the control group. In the paired comparisons of caspase 1 and IL-18, it was found that stage 1 MF, stage 2–4 MF and PLC groups had increased levels of expression compared to the control group. Our findings suggest that the NLRP1 inflammasome pathway might play a role in the etiopathogenesis and progression of PLC and MF. [ABSTRACT FROM AUTHOR]

BACKGROUND: Dermoscopy is a diagnostic technique classically used for the study of pigmented skin lesions, nowadays, its use is gaining strength in inflammatory and infectious diseases, where it can reduce biopsies, and occasionally can give prognostic information. Pityriasis lichenoides chronica is an inflammatory skin disease, part of the papulosquamous dermatosis group. Its diagnosis requires histopathological confirmation. CLINICAL CASES: This paper reports the cases of four Latin-American patients with pityriasis lichenoides chronica and their dermoscopic characteristics. The first case corresponded to a phototype III 25-year-old woman, the second one to a phototype II 61-year-old woman, the third one to a phototype VI 34-year-old man and the fourth one to a phototype IV 36-year-old woman. CONCLUSIONS: In this study, the most frequent dermoscopic features were irregular punctate and linear vessels with clustered distribution, yellow-orange background, focal scales that can vary in color, and the absence of follicular detection. In addition, it was noted that dermoscopic findings may vary according to skin phototypes. [ABSTRACT FROM AUTHOR]

Post-inflammatory hypopigmentation is a common acquired pigmentary disorder that is more prominent in skin of color, leading to great cosmetic and psychosocial implications. Often, a diagnosis with a pigmentary disorder can negatively impact an individual's health-related quality of life and may result in stigma. Although most cases of post-inflammatory hypopigmentation resolve spontaneously over time, a systematic diagnostic approach can help with identifying the underlying etiology and informing treatment strategies. It can be due to cutaneous inflammation, sequelae of inflammatory or infectious dermatoses, or dermatologic procedures. Therefore, a thorough understanding of the epidemiology, patient history, physical exam findings, and clinical features of post-inflammatory hypopigmentation phenomenon can explain the primary cause to providers and allow for patient education. It is also important to understand the various therapeutic approaches available and the efficacy of these options, which will inform providers to choose the appropriate therapy for patients. Although algorithms exist for classifying acquired disorders of hypopigmentation, there are no established algorithms for the diagnosis and treatment of post-inflammatory hypopigmentation, which warrants further exploration and discourse. [ABSTRACT FROM AUTHOR]

Pityriasis lichenoides is an acute and/or chronic skin disease associated with recurrent erythematous papules that self-resolve. While its etiology is unknown, preceding viral infection may play a role. We present an atypical case of a 40-year-old woman with pityriasis lichenoides et varioliformis acuta as a complication of a COVID-19 infection. [ABSTRACT FROM AUTHOR]

Introduction. Pityriasis lichenoides et varioliformis acuta is a rare inflammatory skin disease of unknown etiology and its diagnosis is sometimes established by eliminating diseases that are considered in the differential diagnosis. Given the lack of randomized clinical trials, recommendations for therapy remain based on case reports and case series. Case Report. We present a 63-year-old female patient with generalized skin lesions including, papules, papulonecrotic lesions, and atrophic scars accompanied by a subjective feeling of itching that occurred 2 months before admission. The histopathological findings showed a mixed perivascular inflammatory cellular infiltrate and capillary blood vessels with thickened walls in the superficial part of the dermis as signs of vasculitis. The infiltrate was dominated by lymphocytes, neutrophils were admixed, but there were no signs of cellular atypia, which supported the clinical diagnosis of pityriasis lichenoides et varioliformis acuta. Therapy with systemic corticosteroids and doxycycline was applied, which led to the resolution of lesions. Conclusion. The authors would like to bring to the readers’ attention a rare skin disease, pityriasis lichenoides et varioliformis acuta, point to papulonecrotic tuberculids in differential diagnosis due to similar clinical presentation, remind them of the dilemmas that may arise in case of the described lymphocytic vasculitis based on the findings of histopathological analysis, and highlight the effectiveness of doxycycline and prednisone in the therapy. [ABSTRACT FROM AUTHOR]

The term “pseudomalignancy” covers a large, heterogenous group of diseases characterized by a benign cellular proliferation, hyperplasia, or infiltrate that resembles a true malignancy clinically or histologically. Here, we (i) provide a non-exhaustive review of several inflammatory skin diseases and benign skin proliferations that can mimic a malignant neoplasm in children, (ii) give pathologists some helpful clues to guide their diagnosis, and (iii) highlight pitfalls to be avoided. The observation of clinical–pathological correlations is often important in this situation and can sometimes be the only means (along with careful monitoring of the disease’s clinical course) of reaching a firm diagnosis.

Background: Pityriasis lichenoides (PL) is a papulosquamous disease that affects both adults and children. Previous studies have shown a subset of this entity to have clonal T-cell populations via PCR-based assays. In this study, we sought to implement next-generation sequencing (NGS) as a more sensitive and specific test to examine for T-cell clonality within the pediatric population. Methods: We identified 18 biopsy specimens from 12 pediatric patients with clinical and histopathologic findings compatible with PL. Patient demographics, clinical features, management, and histopathologic findings were reviewed. All specimens were analyzed for clonality with NGS of T-cell receptor beta (TRB) and gamma (TRG) genes. Results: Of the 12 patients, 9 (75%) had complete resolution of lesions at the time of data collection (mean follow-up 31 months). The remaining three patients significantly improved with methotrexate (with or without acitretin). Interestingly, 7 of 12 patients (58%) and 9 of 17 biopsy specimens (53%) showed evidence of T-cell clonality. Two patients showed matching TRB clones from different anatomic sites. Conclusions: T-cell clonality is a common finding in PL, probably representing a "reactive clonality" rather than a true lymphoproliferative disorder. Clonality alone cannot be used as a means to distinguish PL from lymphomatoid papulosis or cutaneous lymphoma. [ABSTRACT FROM AUTHOR]

Pityriasis lichenoides et varioliformis acuta (PLEVA), also known as Mucha-Habermann disease, is an uncommon cutaneous inflammatory disease that mostly affects children and young adults. It usually presents as an acute eruption of inflammatory macules, papules or papulovesicles, which quickly develop haemorrhagic or necrotic crusts. The most severe presentation of the disease is febrile ulceronecrotic Mucha-Habermann disease (FUMHD), which can be potentially life-threatening. This is the reason why we should recognise and start the right treatment of the disease in time.

Pityriasis lichenoides et varioliformis acuta (PLEVA), tudi Mucha-Habermannova bolezen, je redka kožna vnetna bolezen, ki prizadene predvsem otroke in mlade odrasle. Navadno se kaže kot akutni izbruh eritematoskvamoznih makul, papul ali papulovezikul, ki hitro razvijejo hemoragične ali celo nekrotične kruste. Najhujša oblika bolezni, febrilna ulceronekrotična Mucha-Habermannova bolezen (FUMHD), je potencialno življenje ogrožajoče stanje, zato je prav, da bolezen prepoznamo ter pravočasno in ustrezno pristopimo k zdravljenju.

Pityriasis lichenoides chronica (PLC) is a rare, non-infective dermatosis of unknown etiology characterized by reddish-brown papules with potential overlying mica-like scales, which sometimes progress to cutaneous T-cell lymphoma. Lesions mimicking PLC can (rarely) occur as a presentation of anunderlying infectious disease or as a paraneoplastic syndrome

The term "pseudomalignancy" covers a large, heterogenous group of diseases characterized by a benign cellular proliferation, hyperplasia, or infiltrate that resembles a true malignancy clinically or histologically. Here, we (i) provide a non-exhaustive review of several inflammatory skin diseases and benign skin proliferations that can mimic a malignant neoplasm in children, (ii) give pathologists some helpful clues to guide their diagnosis, and (iii) highlight pitfalls to be avoided. The observation of clinical–pathological correlations is often important in this situation and can sometimes be the only means (along with careful monitoring of the disease's clinical course) of reaching a firm diagnosis. [ABSTRACT FROM AUTHOR]

Objective Pityriasis ichenoides consists of Pityriasis Lichenoides et Varioliformis Acuta and Pityriasis Lichenoides Chronica. It might resolve spontaneously and without important sequelae such as lymphoma. This study aims to evaluate the demographic and clinical pictures of both types of pityriasis lichenoides. Methods This is a clinical descriptive study on a long-term basis, in which patients with a clinical picture of pityriasis lichenoides were collected during the period between 2012 and 2020. Any triggering factors before the onset of the disease were noted and biopsies for histopathological evaluation were carried out. Results Fifty-six patients with pityriasis lichenoides were evaluated; no obvious triggering factors were elucidated in both types. The acute form consisted of 16 (80%) males and 4 (20%) females. Their age range was from 5 to30 years with a median of around 17years. All presented with acute generalized erythematous necrotic lesions with burning and itching, simulating chicken pox that left hyperpigmentation after recovery. The chronic form consisted of 36 cases. Their age range was from 3 to 12 years with a median of 7 years; 31 (86%) were males and 5 (13.8%) were females. All cases had a slow course of progression over months and years. Fourteen patients (38.8%) were seen with generalized non-itchy erythematous papules with mica-like scales whereas 24 (66.66%) presented with hypopigmented lesions. Conclusion Both acute and chronic forms are self-limiting conditions that stay for weeks to years and remit spontaneously. They are considered as an immune reaction to specific triggering factors such as an infection. [ABSTRACT FROM AUTHOR]

Competing Interests: None disclosed

We present 12 patients with variants of Pityriasis Lichenoides (PL), including its chronic form (Pityriasis Lichenoides Chronica, PLC), acute form (Pityriasis Lichenoides et Varioliformis Acuta, PLEVA), and the rare and severe Febrile Ulceronecrotic Mucha-Habermann Disease (FUMHD). As these conditions are commonly misdiagnosed, we highlight common clinical and histopathologic diagnostic features. PLEVA and FUMHD were more clinically severe than PLC, although PLC and PLEVA had several overlapping histopathologic features. Infections or vaccinations preceded half of cases, and one patient had suspected mycosis fungoides, providing insights into the pathophysiology of PL. A variety of treatments were used successfully. This case series offers insights into these conditions that can be challenging to diagnose and treat. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Aim: To report a case of a patient with pityriasis lichenoides et varioliformis acuta, emphasising the challenges in the diagnosis and treatment of this clinical entity. Case report: A 30-year-old patient was referred to the Department of Dermatology and Venereology due to skin changes accompanied by itching persisting for one and a half month. Red papules and papulocrusts were found on the trunk, upper and lower limbs, but in a larger number and more severely affecting the trunk than the limbs. The patient stated the occasional use of febuxostat for the treatment of chronic hyperuricemia that has been diagnosed four years prior. Treatment with desloratadine and a combination of bethametasone and gentamicin was started. The laboratory results showed neutropenia, high levels of low density lipoprotein cholesterol and high levels of urate. The biopsy of the skin lesion has been done. Doxycycline treatment and continuing treatment with bethametasone and gentamicin were recommended to the patient. Pathohistological finding described ulcerated epidermis with oedema, granulation tissue and erythrocyte extravasation in the floor of the ulceration. Lymphocytic and histiocytic infiltrates were found in the base of the ulceration and subepidermally. The epidermis on the edge of the ulceration was irregularly hyperplastic and showed spongiosis. The diagnosis of pityriasis lichenoides et varioliformis acuta has been confirmed. Upon completion of doxycycline treatment skin changes were in regression and urate levels decreased. Conclusions: Not only caution in diagnosis and treatment, but also regular follow-up is necessary in patients diagnosed with pityriasis lichenoides et varioliformis acuta because of a wide range of differential diagnoses and a possibility of misdiagnosis. Further research on the etiopathogenesis of this disorder is needed in order to improve treatment outcomes. [ABSTRACT FROM AUTHOR]

Lymphomatoid papulosis is a clinically benign primary cutaneous T-cell lymphoma. Four infantile cases are described, the differences between children and adults are analyzed and the diagnostic difficulties are underlined. The most difficult differential diagnosis is with pityriasis lichenoides, which is characterized by a greater number of lesions and their eruptive monomorphism; on the other hand, the fluctuating trend with crops of new elements that is common to the two diseases has no importance, although in pityriasis lichenoides it is less evident for the greater number of lesions. [ABSTRACT FROM AUTHOR]