Prurigo: review of its pathogenesis, diagnosis, and treatment

Prurigo is a reactive, hyperplastic skin condition characterized by pruritic papules, plaques, and/or nodules. The temporal classification includes acute/subacute and chronic disease (≥ 6 weeks), with different clinical variants, synonymies, and underlying etiological factors. The immunology of chronic prurigo shows similarities with atopic dermatitis due to the involvement of IL-4 and IL-13, IL-22, and IL-31. Treatment includes antihistamines, topical steroids, dupilumab, and JAK inhibitors. Several conditions manifest clinically as prurigo-like lesions, and the correct clinical diagnosis must precede correct treatment. Furthermore, chronic prurigos represent a recalcitrant and distressing dermatosis, and at least 50% of these patients have atopic diathesis, the treatment of which may induce adverse effects, especially in the elderly. The quality of life is significantly compromised, and topical treatments are often unable to control symptoms and skin lesions. Systemic immunosuppressants, immunobiologicals, and JAK inhibitors, despite the cost and potential adverse effects, may be necessary to achieve clinical improvement and quality of life. This manuscript reviews the main types of prurigo, associated diseases, their immunological bases, diagnosis, and treatment.

Comorbidities of Chronic Prurigo: A Systematic Review and Meta-Analysis

BACKGROUND

Chronic prurigo (CPG) is an inflammatory skin disease. Comorbidities including dermatological, cardiovascular, and psychiatric diseases have been reported in patients with CPG; however, the evidence has not been systematically evaluated. We aim to summarize the comorbidities, discuss underlying pathogenesis, and highlight the evaluation of CPG patients.

METHODS

We performed a systematic search using PubMed, Embase, and Web of Science databases for all articles reporting possible associated diseases with CPG. Pooled random-effects odds ratios (ORs) with 95% CI were calculated.

RESULTS

A total of 17 studies were included in this systematic review. Statistically significant association (p <0.05) with CPG has been demonstrated with atopic diseases: atopic dermatitis (pooled OR, 10.91; 95% CI, 3.65-32.67), allergic rhinitis (2.66; 1.12-6.27), asthma (3.23; 1.55-6.74); infectious diseases: hepatitis B (pooled OR, 2.15; 95% CI, 1.11-4.14); endocrine diseases: diabetes (pooled OR, 4.93; 95% CI, 1.13-21.56), type 1 diabetes (2.46; 2.16-2.81), type 2 diabetes (1.89; 1.34-2.68), hyperlipoproteinemia (2.90; 1.61-5.22); cardiovascular diseases: heart failure (pooled OR, 4.13; 95% CI, 1.15-14.91), hypertension (3.17; 1.56-6.45); respiratory system diseases: chronic obstructive pulmonary disease (pooled OR, 3.19; 95% CI, 1.42-7.16); urinary system diseases: chronic kidney disease (pooled OR, 4.16; 95% CI, 1.79-9.66); digestive system disease: inflammatory bowel disease (pooled OR, 2.06; 95% CI, 1.26-3.36); and others: osteoporosis (pooled OR, 3.08; 95% CI, 1.70-5.59), thyroid disease (1.70; 1.17-2.47).

CONCLUSION

CPG is associated with various systemic disorders. Recognition of comorbidities is critical to the appropriate management of affected patients.

A real-world observational study of dupilumab treatment in adult patients with prurigo nodularis

BACKGROUND

Prurigo nodularis (PN) is a chronic inflammatory skin condition that has a significant unmet needs for effective treatment options.

OBJECTIVE

To assess the efficacy and safety of dupilumab in adult patients with PN refractory to traditional therapies.

METHODS

This ongoing, real-life study examined dupilumab treatment in 8 adult patients diagnosed with PN for at least 6 months. The included patients were prescribed 300 mg dupilumab biweekly for at least 16 weeks. Efficacy was the primary outcome by means of multiple standardized scale measurements while safety was also reported.

RESULTS

PN patients treated with dupilumab showed notable clinical improvement. After 16 weeks of dupilumab treatment, the mean Investigator Global Assessment (IGA) score reduced from 3.75 to 1.50. Patients mean Numerical Rating Scale Itch Intensity (NRSI), Dermatology Life Quality Index (DLQI), and Hospital Anxiety and Depression Scale (HADS) ratings reduced from 8.625, 15.13, and 14.50 to 1.563, 4.625, and 1.000 respectively. The majority of the patients (87.5%) reported dupilumab as effective while no adverse events have been reported.

STUDY LIMITATIONS

This study was limited to a small cohort of adult PN patients and a short-time observation period.

CONCLUSIONS

Dupilumab is effective and tolerable in adult PN patients with significant improvement in skin lesions, itching, and quality of life.

[Novel aspects of the current guideline for chronic pruritus]

Chronic pruritus is still a major challenge for patients and treating doctors, as chronic pruritis mostly constitutes a difficult to treat symptom of different diseases. In this article we summarize the most recent changes of the current German guidelines on chronic pruritus and give practical recommendations for the diagnosis and therapy.

Immunohistochemical Analysis of Prurigo Nodularis in 209 Patients: Clinicopathological Analysis between Atopic and Non-Atopic Patients and between Treatment Response Groups

Background

Prurigo nodularis (PN) is a highly pruritic disease that significantly impairs patient quality of life. Although the mechanism that causes pruritus is not clear, one hypothesis argues that neural hyperplasia, mast cell, and Merkel cell neurite complexes may be associated with PN pathogenesis.

Objective

The objective of this study was to analyze whether special staining outcomes differed depending on the presence of atopic dermatitis (AD) and treatment response.

Methods

A total of 209 patients diagnosed with PN was analyzed retrospectively. Patients were divided into two groups according to presence or past history of AD and by treatment response. Histopathologic features were obtained using the following stains: Giemsa, S-100, neuron-specific enolase, cytokeratin (CK)-20, CAM5.2, and CK8/CK18.

Results

A total of 126 patients (60.29%) had AD, and 68 (32.54%) showed clinical improvement. There were no statistically significant differences in the staining results between the PN groups with AD (PN c AD) and without AD (PN s AD). Additionally, there were no statistically significant differences in staining results between the improved and non-improved groups.

Conclusion

Implementing the special stains helped to identify PN pathogenesis. Because there were no statistically significant differences in the special stain results between the improved and non-improved groups, we conclude that mast cell proliferation, neural hyperplasia, and Merkel cell hyperplasia may not have a significant effect on treatment response.

Localized Scarlatiniform Rash of the Ears and Antecubital Fossa in COVID-19

The worldwide spread of the novel coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to a global pandemic since its identification in Wuhan, China in December 2019.¹ Few cases of COVID-19-associated dermatologic manifestations have been reported in the literature to date. This report describes the clinical features of a localized pruritic scarlatiniform rash of the ears and antecubital fossa on defervescence in a 29-year-old patient with COVID-19. Our case stands to further illuminate the dermatologic manifestations of this novel disease.

The impact of prurigo nodularis on quality of life: a systematic review and meta-analysis

Prurigo nodularis (PN) is a chronic, pruritic, debilitating disease. Previous studies found that chronic pruritus in general negatively affects patients' quality of life (QoL). However, results about the impact of PN on QoL are conflicting. Our objective was to assess the QoL burden of PN. A systematic review was conducted of all published studies that assessed QoL measures in PN. OVID MEDLINE, EMBASE, SCOPUS, and Web of Science were searched. Pooled meta-analysis (means) was performed using random-effects weighting. Overall, 13 studies met inclusion criteria. All studies identified QoL reductions in patients suffering from PN compared to control groups. The most common QoL instrument used was the Dermatology Life Quality Index [n = 9 studies; pooled mean (95% confidence interval): 13.8 (10.6-16.9), denoting a very large effect]. In particular, PN was associated with substantial impact on multiple domains of QoL. No publication bias was detected. In conclusion, QoL is negatively impacted in PN. Future studies are necessary to determine the best instruments of measuring QoL in PN patients, better understand this association, and assess the impact in males and females separately. PROSPERO CRD42019136193.

Actinic prurigo in a dermatological reference center in Colombia: 108 cases

Introducción.

El prurigo actínico es una fotodermatosis crónica. Afecta con mayor frecuencia a la población latinoamericana, predomina en mujeres y compromete la piel expuesta al sol, las conjuntivas y los labios.

Objetivo.

Actualizar la información sobre las características clínico-epidemiológicas y el tratamiento de pacientes con prurigo actínico en Colombia.

Materiales y métodos.

Se hizo un estudio de corte transversal que incluyó los registros clínicos de pacientes con prurigo actínico atendidos en el Servicio de Fotodermatología del Hospital Universitario Centro Dermatológico Federico Lleras Acosta entre el 2011 y el 2016, y se describieron sus características demográficas, clínicas e histopatológicas, así como su tratamiento.

Resultados.

Se incluyeron 108 pacientes, el 71,3 % de ellos mujeres y el 28,7% hombres, con predominio de los fototipos III-IV (70 %). La enfermedad se había iniciado durante la primera década de vida en el 66,4% de los casos y el 25 % de los pacientes tenía antecedentes familiares de la enfermedad. Las lesiones predominaban en el rostro (93,5 %), los antebrazos (79,6 %) y el dorso de las manos (70,4 %). También, se documentó compromiso ocular (87,9 %) y de los labios (88,8 %). Se hizo la prueba de fotoprovocación con radiación ultravioleta A en el 25 % de los casos y biopsia cutánea en el 19,4 %. Todos los pacientes se trataron con protección solar química y física. En los casos leves a moderados, se formularon corticoides tópicos (91,7 %) e inhibidores de la calcineurina (65,7 %), y en los graves, talidomida (33,3 %) y pentoxifilina (14,8 %).

Conclusión.

Las características de los pacientes colombianos con prurigo actínico son similares a las reportadas en otros países latinoamericanos: inicio temprano de la enfermedad, predominio en mujeres, compromiso frecuente de conjuntivas y labios, y adecuada respuesta al tratamiento tópico y sistémico.

[Antihistamines for treating pruritus : The end of an era?]

Antihistamines, mostly H1 antihistamines, administered both topically and systemically, are among the most widely used drugs. While systemically applicable antihistamines are usually taken orally or administered intravenously, while local therapy is used on the eye, nose or skin. Systemic antihistamines are most frequently used during the pollen season (hay fever, asthma) or are used all year round, e.g., for house dust and animal hair allergies. Furthermore, urticaria is a major indication for the use of H1 antihistamines, also as long-term treatment. Although H1 antihistamines are not licensed for pruritus and prurigo, they are frequently used in these diseases. However, since in many diseases with pruritus and prurigo the histamine receptor does not play a decisive role in the pathogenesis of pruritus, they show limited efficacy. Two Cochrane reviews have not shown any significant antipruritic effects of H1 antihistamine treatment in atopic eczema as single therapy or in combination, e.g., with topical glucocorticosteroid therapy. A retrospective case series with a so-called high-dose antihistamine therapy with non-sedating antihistamines was effective in treating chronic pruritus. This article summarizes the possibilities of systemic antihistamines in pruritus, especially with regard to limitations and future prospects.

[Prurigo nodularis]

Prurigo nodularis. Prurigo nodularis is the most severe degree of chronic prurigo. Disseminated nodules (mostly on the 4 members) are associated with skin excoriations and an intense pruritus. Whatever the etiology, prurigo nodularis is autonomous disease which is related to itch sensitization (similar to pain sensitization). The burden is high. A management with different levels is recommended and the opinion of a dermatologist is frequently required. Research gives promising therapeutic perspectives.

[Gamasoidosis caused by Dermanyssusgallinae]

INTRODUCTION

Mite parasites can be transmitted from animals to humans and cause prurigo.

OBSERVATION

We describe a case of mite transmission in a 75-year-old woman referred for pruritus and erythematous maculopapular rash. On clinical examination mites were seen on the patient's skin. The mites were collected and characterized using microscopy. The species was identified as Dermanyssusgallinae, also known as the poultry red mite, an ectoparasite that commonly infests bird nests. The source of the patient's contamination was her henhouse, where mites were found in the wooden beams. Molecular analysis by mitochondrial DNA sequencing was performed on a mite collected from the patient and on a mite collected from the henhouse. This analysis confirmed that both belonged to the D. gallinaes.str species, and that the source of contamination was poultry farming.

CONCLUSION

This case describes transmission to a human of the mite D. gallinaes.str via hens, resulting in prurigo, as confirmed by morphological and molecular analysis.

[Epidemiological and clinical aspects of prurigo in HIV infected patients in Fousseyni N'Daou hospital of Kayes, Mali]

INTRODUCTION

Prurigo is one of the most common dermatological conditions during HIV infection and AIDS. It appears as an immunosuppression marker associated with HIV infection. The study objective was to determine the prevalence of prurigo in people living with the human immunodeficiency virus (PLHIV) in Fousseyni N'Daou Hospital of Kayes, and to describe the socio-demographic aspects of patients and lesions associated with prurigo among PLHIV.

METHODS

It was a descriptive cross-sectional study included all cases of HIV infected patients with prurigo in the Dermatology-Venomology Department of Fousseyni N'DAOU Hospital from January 1, 2015 to August 31, 2015.

RESULTS

We collected 121 cases of prurigo. The hospital prevalence was 14.5% among PLHIV with 65% Female and the average age was 34.8 years old (SD: 15-81 years). The elementary lesions associated with prurigo were seropapules (40.2%), vesiculo-crusts (13%), excoriated papules (33.3%), lichenified papules (10.8%), and cicatricial lesions (2.7%). The prurigo was generalized in 68.5% of cases and localized in 31.24%. More than half of our patients had weight loss, fever, diarrhea and oral candidiasis in their medical history. Patients were infected with HIV1 in 60.03% and HIV1+ 2 in 24.3%. More than the half of our patients had a CD4 count inferior to 250 cells/mm3 at the time of prurigo diagnosis.

CONCLUSION

In our study, prurigo remains a common condition in PLHIV, particularly in patients with low CD4 counts. Early detection and rapid antietroviral therapy can reduce the frequency of prurigo in PLHIV.

[Chronic pruritus : Care in daily practice]

Chronic pruritus is a highly prevalent, multifactorial symptom requiring extensive diagnostics, treatment and consideration of accompanying symptoms (reduced quality of life, sleep disorders, psychic factors). Patient care is thus complex and requires consideration of individual treatment goals. Patients indicate their wish for a symptom-free life an explanation of the causes and a trustful physician-patient relationship. The targeted use of questionnaires is thus advisable in order to structurally survey the history, pruritus intensity, quality of life and treatment progression. Nevertheless, there are many administrative and economical hurdles in the health care system to overcome in order to provide patients with chronic pruritus the best possible care, also per the recommended guidelines. The development of specialized centers and training courses for medical practitioners is thus urgently needed.

Pseudoperforation: an uncommon histologic phenomenon in prurigo misleading for the diagnosis of reactive perforating collagenosis

Prurigo is a common skin condition characterized by vigorous scratching. Although ulceration is not uncommon in prurigo, a perforating-like lesion was not previously reported. In this study we described series of cases of prurigo with perforating-like lesions and discussed its relation to acquired perforating dermatoses. The study included 32 cases, during the period from 2008 to 2013. Clinical data and histological features were recorded and analyzed. The study included 78.1% males and 21.9% females with a mean age of 39.3 ± 5.61 years. History of insect bite was evident in 28.1%, hepatitis C virus infection in 46.9%, and diabetes mellitus in 9.4% of patients. Histologically, well developed lesions showed full thickness epidermal degeneration overlay by a cup-shaped crater. The contents of the crater included collagen and elastic fibers, bacterial colonies, inflammatory cells and necrotic keratin. The dermis showed non-altered collagen, increased vascularity and mixed inflammatory infiltrate. We believe that this pseudoperforation process is a secondary response to vigorous scratching in prurigo patients and not a primary mechanism as occurred in perforating dermatoses. The absence of altered collagen, the presence of full thickness epidermal necrosis and concomitant elimination of elastic fibers are significant histologic clues for differentiation between both conditions.