Actinic conjunctivitis and its relationship with prurigo in an indigenous population from the Highlands of Chiapas, Mexico.

PURPOSE: Actinic conjunctivitis (AC), along with cheilitis (AChe), is part of the clinical spectrum of actinic prurigo (AP), a rare photo dermatosis that affects high-risk populations. We analyzed the clinical manifestations and onset of actinic conjunctivitis (AC), and its relationship with prurigo (AP) in a susceptible population. METHODS: This prospective observational cohort study was performed on Indigenous populations from the highlands of Chiapas, Mexico. Thorough dermatological and ophthalmological examinations were performed in patients attending a primary health care center. The clinical features, labor and environmental factors, onset timing, and clinical staging of AC and AP were analyzed. RESULTS: Of the 2913 patients studied, 54 patients (108 eyes) (1.8%) had AC, and 14 patients (25.9%) had AP. The mean age at diagnosis was 36.18 ± 18.52 years (6-70 years). The mean residential altitude was 1884 ± 434.2 m above sea level. Mean self-reported sun exposure was 5.14 ± 3.1 h a day (0.5-12 h). A total of 90.7% reported exposure to biomass fuels during cooking, and 50% to farm animals. AC was the sole manifestation in 70% of the cases. All patients had nasal and temporal photo-exposed conjunctiva. Among the eyes, 12.9% were classified as stage-1, 64.8% as stage-2, and 22.2% stage-3. A total of 83.3% of the patients had hyperpigmented lesions, and 35.1% had evaporative dry eye disease. CONCLUSIONS: AC may be the initial or sole manifestation of AP. Most AC cases (87%) were initially observed at the advanced stages of the disease. Although solar exposure was not associated with late AC stages, a positive association was found with farm animal exposure. Evaporative dry eye associated with meibomian gland dysfunction has not been previously reported in patients with AC.

New insight into prurigo nodularis: Proadrenomedullin N-terminal 20 peptide mediates mouse mast cell activation via Mrgprb2.

BACKGROUND: Prurigo nodularis (PN) is a chronic inflammatory skin disorder that is characterized by extremely itchy nodules. Proadrenomedullin N-terminal 20 (PAMP) activates mast cell degranulation via Mas-related G protein-coupled receptor X2 (MRGPRX2), which is associated with pruritus in allergic contact dermatitis. However, the mechanisms underlying the action of PAMP and MRGPRX2 in PN remain unclear. OBJECTIVE: To determine the role of PAMP-induced mast cell activation via MRGPRX2 (mouse homologous Mrgprb2) in PN. METHODS: The expression of PAMP and the number of MRGPRX2-expressing mast cells in the skin biopsies of patients with PN, atopic dermatitis (AD), and healthy participants were analyzed using immunohistochemistry and immunofluorescence, respectively. The biphasic response of PAMP9-20 mediated by Mrgprb2 in mouse peritoneal mast cells (PMC) was validated in vitro using qRT-PCR, ELISA, flow cytometry, and siRNA techniques. RESULTS: PAMP expression and the number of MRGPRX2+ mast cells in lesional PN skin, but not in AD, were elevated compared to healthy skin. PAMP9-20 mediates the immediate and delayed phase responses of PMC, such as degranulation, histamine and ß-hexosaminidase release, and secretion of inflammatory factors such as CCL2, TNF-α, and GM-CSF. These effects were inhibited when Mrgprb2 expression was silenced. Silencing Mrgprb2 did not affect the biphasic response of PMC that was induced by IgE-FcεRI activation. CONCLUSIONS: The results show that PAMP mediates mouse mast cell activation via Mrgprb2, which may be involved in the pathogenesis of PN. The PAMP/ Mrgprb2 pathway, independent of classical IgE signaling, could be developed as a candidate drug target for treating PN.

Prurigo of pregnancy.

A primigravida in her 20s, with 38 weeks period of gestation, came to the emergency ward of obstetrics wing with complaints of extensive itching over the extremities. On local examination, there were multiple, discrete, hyperpigmented papules topped with depigmentation and excoriations on upper and lower extremities. These are of 0.5-1 cm in size and some have central crusts . On clinical findings and exclusion of other pathologies, it was diagnosed as prurigo of pregnancy. The patient had an uneventful follow-up period.

Molecular mechanisms of pruritus in prurigo nodularis.

Pruritus is the most common symptom of dermatological disorders, and prurigo nodularis (PN) is notorious for intractable and severe itching. Conventional treatments often yield disappointing outcomes, significantly affecting patients' quality of life and psychological well-being. The pathogenesis of PN is associated with a self-sustained "itch-scratch" vicious cycle. Recent investigations of PN-related itch have partially revealed the intricate interactions within the cutaneous neuroimmune network; however, the underlying mechanism remains undetermined. Itch mediators play a key role in pruritus amplification in PN and understanding their action mechanism will undoubtedly lead to the development of novel targeted antipruritic agents. In this review, we describe a series of pruritogens and receptors involved in mediating itching in PN, including cytokines, neuropeptides, extracellular matrix proteins, vasculogenic substances, ion channels, and intracellular signaling pathways. Moreover, we provide a prospective outlook on potential therapies based on existing findings.

Clinical and Pathological Spectrum of Prurigo Pigmentosa in Central European Individuals.

Importance: Based on early studies, prurigo pigmentosa (PP) was considered a rare inflammatory dermatosis affecting primarily Asian individuals. However, several case reports subsequently showed that the disease is not restricted to those of Asian origin. Large studies on PP in central European individuals, on the other hand, are missing. Objective: To increase awareness of PP by describing the clinical, histopathological, and immunohistochemical features in central European individuals. Design, Setting, and Participants: This observational, retrospective case series analyzed clinicopathological features of 20 central European patients diagnosed with PP. Data collection was performed by means of archive material, including physician's letters, clinical photographs, and histopathological records, at the Department of Dermatology at the Medical University of Graz in Austria from January 1998 to January 2022. Main Outcomes and Measures: Demographic, clinical, histopathological, and immunohistochemical characteristics for patients diagnosed with PP were recorded. Results: Of the 20 patients included, 15 (75%) were female, and the mean (range) age was 24.1 (15-51) years. The study cohort consisted entirely of European patients. The most common site of involvement of PP was the breast, followed by the neck and back. Other involved clinical sites were the abdomen, shoulders, face, head, axillae, arms, and genital region and groin. Clinically, lesions were characterized by a symmetric pattern in 90% (n = 18) of all cases. Marked hyperpigmentation was observed only in 25% (n = 5) of patients. In some cases, triggers such as malnutrition, long-term pressure, and friction were noted. Histologic findings revealed presence of neutrophils in all cases and necrotic keratinocytes in 67% (n = 16) of cases. Immunohistochemistry results showed predominance of CD8+ lymphocytes in the epidermis, as well as the presence of plasmacytoid dendritic cells and myeloid cell nuclear differentiation antigen-positive neutrophil precursors. Conclusions and Relevance: This case series found that most clinical features observed in Asian patients were also observed in central European patients, but hyperpigmentation was primarily mild to moderate. Histopathological features were similar to those reported in the literature with the additional presence of myeloid cell nuclear differentiation antigen-positive precursor neutrophils. These results expand previous knowledge about PP in central European individuals.

RNA sequencing reveals the transcriptome profile of the atopic prurigo nodularis with severe itching.

Prurigo nodularis (PN), characterized by inevitable chronicity and severe pruritus, is most frequently associated with atopy compared with other origins. However, the skin transcriptomic profiling of PN arising from atopic dermatitis (AD), so-called atopic PN (APN), remains unclear. We sought to explore the cutaneous transcriptome of APN with severe pruritus and compare it with classic AD. RNA sequencing was performed on the lesional skin from 13 APN to 11 AD patients with severe pruritus (itch numerical rating scale score ≥ 7) and normal skin from 11 healthy subjects. Quantitative real-time polymerase chain reaction and immunochemistry were used for validation. We detected 1085 and 1984 differentially expressed genes (DEGs) in lesional APN skin and lesional AD skin versus normal skin, respectively. In total, 142 itch/inflammation-related DEGs were identified. Itch/inflammation-related DEGs, such as IL-6, IL-10, IL-13, oncostatin M, and IL-4 receptor, had elevated gene transcript levels in both diseases. The itch/inflammation-related DEGs that increased only in APN were mainly neuroactive molecules, while many inflammatory mediators such as T helper 22-related genes were found to be increased only in AD. Both disorders showed mixed Th1/Th2/Th17 polarisation and impaired skin barrier. In contrast to AD, M1/M2 macrophage activation, tumor necrosis factor production, fibrosis, revascularization and neural dysregulation are unique features of APN. The study findings broaden our understanding of the pathogenesis underlying APN, which provides insights into novel pathogenesis with potential therapeutic implications.

[Eosinophilic dermatoses]. / Eosinophile Dermatosen.

Eosinophilic dermatoses are a heterogeneous group of rare diseases that histopathologically display the defining pattern of an eosinophil-rich dermal infiltrate. In these eosinophilic dermatoses, a histopathologic pattern called flame figures, which result from degranulation of eosinophils in the tissue, can be observed. Although eosinophil granulocytes can also be detected in other dermatoses such as atopic dermatitis, urticaria, prurigo and bullous pemphigoid, the eosinophil-rich infiltrate is decisive for classic eosinophilic dermatoses. Accordingly, eosinophilic dermatoses include hypereosinophilic syndrome, eosinophilic fasciitis, granuloma faciale, pustular sterile eosinophilia, and angiolymphoid hyperplasia with eosinophilia. These eosinophilic dermatoses display clinical different patterns and are discussed in this article, as well as the interesting eosinophils and novel therapeutic options.

Case Report: Pemphigoid Nodularis-Five Patients With Many Years of Follow-Up and Review of the Literature.

Pemphigoid nodularis is a rare form of pemphigoid that joins the clinical picture of prurigo nodularis and the immunological features of bullous pemphigoid, which is therapeutically challenging. Here, we analyze five female patients with a long-lasting course of nodular pemphigoid in terms of clinical and immunological characteristics and therapy. All the patients fulfilled clinical and immunological criteria of nodular pemphigoid. We applied numerous techniques allowing the proper diagnosis: direct and indirect immunofluorescence, salt split skin, ELISA, BIOCHIP, and fluorescence overlay antigen mapping using laser scanning confocal microscopy. Our study showed that 4 of 5 patients fulfilled the clinical and immunological criteria of nodular bullous pemphigoid. Two out of 4 patients presented exclusively nodular lesions; in the other two patients, blisters and erythematous lesions preceded prurigo-like lesions by a few years. The remaining patient had clinical and immunological criteria of nodular mucous membrane pemphigoid, presenting oral erosions, scarring conjunctivitis, and numerous disseminated nodules on the skin. All the patients were treated with multiple medicines; however, it was observed that the use of clobetasol propionate on the entire body plus antidepressants best controlled the disease. Pemphigoid nodularis mainly occurs in elderly women. In cases with coexisting psychological problems, antidepressants should be considered as an important complementary therapy to the basic one with clobetasol propionate.

Prurigo pigmentosa following a ketogenic diet: a case report.

A 19-year-old female of South Asian descent presented with a three-day history of pruritic, clustered papules and vesicles on her abdomen, associated with significant pruritus and intermittent pain. She commenced a ketogenic diet four days prior to the emergence of the rash. Histopathological and clinical findings were in keeping with prurigo pigmentosa, an uncommon dermatosis characterised by pruritic, erythematous papules and vesicles presenting reticulated on the back, chest and neck. Prurigo pigmentosa may be distinguished from many other skin lesions by its reticular pattern. Its pathogenesis is unknown, but it has been hypothesised to be induced by a state of ketosis. Clinicians should therefore be aware of its association with the increasingly popular ketogenic diet. This dermatosis responds well to tetracyclines and has an excellent prognosis. In the patient with ketosis-induced prurigo pigmentosa, administration of insulin or an increase in carbohydrates can also resolve symptoms.

Prurigo nodular crónico / Chronic nodular prurigo

El prurigo nodular crónico se caracteriza por un ciclo de prurito y excoriación en el que intervienen mecanismos neurodérmicos, asociado a diversas enfermedades. Se manifiesta con placas o nódulos hiperqueratósicos cupuliformes. El tratamiento, enfocado en reducir el prurito, representa un desafío por la frecuente resistencia a las terapéuticas habituales. Se describe el caso de un hombre de 72 años, con antecedentes psiquiátricos, que presentó una dermatosis pruriginosa recalcitrante refractaria a múltiples esquemas de tratamiento.

Chronic prurigo nodularis is characterized by a cycle of itching and excoriation involving neurodermal mechanisms, associated with various diseases. It manifests with cupuliform hyperkeratotic plaques or nodules. Treatment is focused on reducing itching and is a challengue due to the frequent resistance to the usual therapies. We present the case of a 72-year-old man with a psychiatric history, who presented a recalcitrant pruritic dermatosis refractory to multiple treatment regimens.

Application of least absolute shrinkage and selection operator logistic regression for the histopathological comparison of chondrodermatitis nodularis helicis and hyperplastic actinic keratosis.

BACKGROUND: The distinction between chondrodermatitis nodularis helicis (CNH) and hyperplastic actinic keratosis (HAK) on the ear can pose a diagnostic challenge. We aimed to identify histopathological characteristics that could distinguish between CNH and HAK on routine sections using penalized least absolute shrinkage and selection operator (LASSO) logistic regression analysis. METHODS: Cases of CNH (n = 80) and HAK (n = 28) were analyzed for selected histopathological characteristics. Fisher's exact test and LASSO regression were performed. RESULTS: In univariate analyses, the following were significantly associated with CNH: ulceration, acanthosis, granular layer in the majority of the lesion, hypergranulosis at the periphery of the lesion, hyperkeratosis at the periphery of the lesion, hyperparakeratosis at the periphery of the lesion, fibrosis, increased blood vessels, vertically oriented blood vessels, and fibrin. A LASSO model excluding atypia found that fibrin, fibrosis, presence of granular layer, ulceration, and vertically oriented blood vessels were most predictive of CNH. Keratinized strap cells were not a significant predictor. CONCLUSION: We have identified features that may aid in differentiating these entities and demonstrated that a LASSO regression model can identify predictors that may improve diagnostic accuracy. Our results indicate that the highest diagnostic accuracy in this dilemma is dependent on obtaining biopsy specimens with visible dermis.

Prurigo Pigmentosa: Demographics and Characteristics in 14 Caucasian Patients.

BACKGROUND: Prurigo pigmentosa (PP) is an inflammatory dermatosis typically reported in young Asian women and characterized by recurrent papulovesicular lesions resolving with a postinflammatory reticulated hyperpigmentation. METHODS: We have included all consecutive patients with PP diagnosed in our tertiary center between 2013 and 2020. The clinical information was retrospectively collected from medical records. RESULTS: We identified 14 patients with PP. The median age at the time of diagnosis was 29.5 years (range 17-43 years), while the female-to-male ratio was 13:1. Diagnostic delay varied from 10 days to 10 years (mean of 25 months). Light microscopy studies consistently showed presence of a lymphohistiocytic infiltrate in combination in 40% of cases with neutrophils. Interface changes were found in 60% of cases. In 6 (43%) of 14 cases, there was a chronological relationship between the starting of a new diet and the development of the first flares. Treatment with doxycycline in 9 patients resulted in a complete regression of the lesions. LIMITATION: This was a retrospective study in a tertiary referral hospital. CONCLUSIONS: Our observations indicate that PP is not so rare in Europe as previously thought and is often diagnosed after a long delay. Demographics, clinical characteristics and triggering factors in Caucasian patients are similar to those described in the Asian population. Diagnosis is based on the peculiar recurrent course and distinctive clinicopathological features. Tetracyclines represent the first-line therapy in PP.