Actinic Prurigo Patients Research Articles

The Immunogenetics of Photodermatoses.

Photodermatosis is an abnormal skin inflammatory reaction to light. The major classifications of photodermatoses are idiopathic photodermatoses, photodermatoses due to exogenous or endogenous agents, photo-exacerbated dermatoses, and photosensitive genodermatoses. In this chapter, we focus on idiopathic photodermatoses and drug-related photodermatoses and emphasize on the epidemiology and immunogenetic backgrounds. Idiopathic photodermatoses, a spectrum of diseases with abnormal responses to ultraviolet radiation (UVR), include polymorphous light eruption, actinic prurigo, hydroa vacciniforme, chronic actinic dermatitis, and solar urticaria. Young people are more susceptible to most idiopathic photodermatoses except for chronic actinic dermatitis. Interestingly, idiopathic photodermatoses exhibit different characteristics between Caucasians and Asians. For example, the average age of Asian actinic prurigo patients is older than that of Caucasians in which genetic backgrounds or Fitzpatrick skin type might play a role. Drug-induced photodermatoses can be classified into phototoxic and photoallergic drug reactions. Certain drug-induced photodermatoses may mimic other dermatoses. For instance, drug-induced lupus erythematosus (LE) should be considered if an old man is diagnosed with LE but had a poor response to standard treatments.

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

ResumenIntroducción. 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.

Actinic Prurigo in Singaporean Chinese: A Positive Association with HLA-DRB1*03:01.

Studies have reported the association of human leukocyte antigen (HLA) genes with susceptibility to develop actinic prurigo (AP) in Caucasians, but there were no studies in Asian populations, including the Chinese. Our study was performed to determine if AP is associated with susceptibility or protective HLA alleles or haplotypes in Singaporean Chinese. All Chinese patients diagnosed with AP at National Skin Center, Singapore, from January 2002 to April 2015 were invited to participate in the study. Clinical data and phototesting results were collated, and HLA typing was performed. Among 14 patients included, 11 were male and the mean age was 49.6 (37.9-61.3) years. All patients did not have a family history of AP and none had mucosal involvement, as such these clinical features differed from Caucasian AP patients. The frequency of DRB1*03:01 in AP patients was significantly higher compared to healthy controls (43% vs 16%, P = 0.022, odds ratio (OR) 3.89). Concurrently, the frequency of HLA-B*58:01-DRB1*03:01 haplotype was also significantly increased (25% vs 7%, P = 0.004, OR 4.23). In conclusion, HLA-DRB1*03:01 was associated with AP in Singaporean Chinese patients. This novel allelic association may possibly be utilized as a biological marker to aid in the diagnosis of AP in Chinese patients.

Correlation of serum IgE levels and clinical manifestations in patients with actinic prurigo.

BACKGROUND:Actinic prurigo is an idiopathic photodermatosis, the pathophysiology of which has been hypothesized to involve subtype IV type b (Th2) hypersensitive response, whereby IL4, IL5, and IL13 are secreted and mediate the production of B cells, IgE, and IgG4.OBJECTIVES:To examine the association of serum IgE levels and the clinical severity of injuries.METHODS:This case-control study comprised patients with a clinical and histopathological diagnosis of actinic prurigo, as well as clinically healthy subjects, from whom 3cc of peripheral blood was taken for immunoassay. Cases were classified by lesion severity as mild, moderate, and severe. Descriptive statistics were analyzed, and chi-square test was performed.RESULTS:We included 21 actinic prurigo patients and 21 subjects without disease; 11 patients with actinic prurigo had elevated serum IgE levels, and 10 had low serum levels. Six actinic prurigo (AP) patients with elevated serum levels of IgE had moderate injuries, 4 had severe injuries, and 1 had minor injuries. Eight out of 10 patients with normal IgE levels presented with minor injuries in the clinical evaluation. The 21 controls did not have increased serum IgE levels.CONCLUSIONS:Elevated IgE levels are associated with moderate to severe clinical lesions, suggesting that actinic prurigo entails a type IV subtype b hypersensitivity response in which Th2 cells predominate.

Epidermal Langerhans cells in actinic prurigo: a comparison between lesional and non-lesional skin

Actinic Prurigo (AP) is a chronic pruritic dermatosis of unknown cause affecting sun exposed skin in defined ethnic groups with characteristic MHC alleles. However, the cutaneous dendritic cells have not been assessed. To assess in situ the epidermal Langerhans Cell (LC) status in Actinic Prurigo. Fresh skin samples from three AP patients were used to evaluate in situ the epidermal LC, comparing lesional and non-lesional sites in each subject. AP patients attending the Dermatology Department at the Hospital M. Gea-Gonzalez in Mexico city. Lesional and non-lesional skin samples were taken from each subject to prepare both epidermal sheets and conventional tissue sections. Three markers restricted to LC in epidermis (CD1a, ATPase, MHC-II) were used to quantify the LC per area in epidermal sheets. Compared to non-lesional skin from the same subject, a significant reduction in the number of LC per area of epidermis was found in lesional skin; with any of the three markers evaluated. The frequency of epidermal LC decreases importantly in lesional skin from AP patients.

Association of HLA subtype DRB1*0407 in Colombian patients with actinic prurigo

Human leukocyte antigen (HLA) DRB1*0407 had been associated with actinic prurigo in different populations. This class II HLA-DR subtype had not been studied in Colombia. The objective of this study was to establish whether there was an association of actinic prurigo with HLA DR in a Colombian population. Forty patients with a clinical diagnosis of actinic prurigo and 40 healthy subjects, paired by age, sex and birthplace, were studied. HLA typing for HLA DRB1 and DRB1*04, if necessary, was performed by the PCR-SSP method using blood samples. A high frequency of HLA DRB1*0407 was found in the patients (97.5% vs. 30%; P<0.00001). The allelic frequency of HLA DRB1*0407 was 63.8% in the case group, and 14.5% in the controls (P<0.00001). In the control group, there was a higher frequency of the alleles DRB1*01 (14.5% vs. 1.25%; P=0.0027) and DRB1*13 (23.7% vs. 2.5%; P=0.00013). The small number of controls does not allow us to drive conclusions about other HLA alleles. HLA subtype DRB1*0407, found in actinic prurigo patients in studies conducted in England, Scotland, Ireland and Mexico, was also associated in Colombian patients. This finding, concordant in patients from different ethnic groups, could be helpful in the diagnosis of this disease and probably important in its pathogenesis. DRB1*01 and DRB1*13 alleles were more frequent in controls than in patients; we do not know whether they play any role in the resistance to the disease.

Pentoxifylline in the Treatment of Actinic Prurigo

Background: Actinic prurigo (AP) is a chronic familial photodermatosis usually seen in Latin-American Mestizo and Indian populations. It frequently begins in childhood and is more prevalent in females. The pathogenesis of AP has not been clearly elucidated, but previous studies have suggested an immune-mediated condition. Many drugs have been employed to treat AP patients with variable success. Objective: To assess the clinical efficacy of pentoxifylline (PTX) in the treatment of AP patients by measuring its effects on lesions and pruritus. Methods: 10 patients with severe AP were included to receive PTX in a 6-month open-label uncontrolled study. Results: Clinical improvement of lesions was evident in all patients. Relief in pruritus was evident after 1 month of treatment and was maintained while receiving PTX. Five patients were followed up for 2 years, 2 obtained complete remission, and 3 had an important reduction in the use of corticosteroids. Conclusion: PTX was useful in the treatment of our actinic prurigo patients. It may induce a complete or partial remission of lesions and allow a decrease in the use of topical corticosteroids.

Lymphocyte subtypes and adhesion molecules in actinic prurigo: observations with cyclosporin A.

Actinic prurigo is a photodermatitis in which UV light is implicated by an unknown mechanism. Skin biopsies of 19 patients with actinic prurigo and 11 controls were analyzed by immunohistochemistry. In actinic prurigo patients, there was a significant increase in the number of CD3, CD4, CD8, CD45RA, CD45RO, and CD45RB lymphocytes and Langerhans cells, as well as in the level of human leukocyte antigen-DR (HLA-DR) expression and cell adhesion molecules lymphocyte functional antigen-1 (LFA-1), intercellular adhesion molecule-1 (ICAM-1), and endothelial leukocyte adhesion molecule-1 (ELAM-1). Actinic prurigo patients were treated with cyclosporin A (CsA), and a final skin biopsy was taken after 6 months of treatment. All the cell populations and markers studied, except for the CD4 lymphocytes, Langerhans cells, and HLA-DR expression, returned to normal levels. CsA was found to be effective in relieving the clinical symptoms of actinic prurigo.

Actinic prurigo and polymorphic light eruption: common pathogenesis and the importance of HLA-DR4/DRB1*0407.

Actinic prurigo (AP) and polymorphic light eruption (PLE) both belong to the group of idiopathic photodermatoses, but it remains controversial whether AP is a distinct photodermatosis or a variant of PLE. The aim of this study, by collecting data from 119 patients with features of these disorders, was to establish whether specific criteria could be used to distinguish AP from PLE prospectively. We found that presence of the eruption on both exposed and covered sites, its occurrence in winter, persistence of lesions beyond 4 weeks, mucosal and conjunctival involvement, excoriation and scarring of the skin were important features of AP which were not typical of PLE. On this basis, confident clinical diagnoses could be reached in 103 of 119 patients (87%), 57 with AP and 46 with PLE, supported by phototesting and negative lupus serology. HLA typing subsequently confirmed the strong association (90%) between AP and the DR4 allele, in particular with the rare subtype DRB1*0407 which was present in 60% of these patients. No HLA association was found in PLE. In the 16 remaining cases, however, clinical overlap meant that no definite diagnosis could be made; these patients were notionally described as having persistent PLE (PPLE). Demographic and HLA data in this group suggested that PPLE was perhaps most appropriately grouped with PLE. In addition to those patients who were difficult to classify, 35% of our typical AP patients also described clinical progression from PLE to AP, AP to PLE or coexistence of both AP and PLE. In conclusion, our study suggests that while AP and PLE are clinically distinct conditions in most cases, they may perhaps share a common pathophysiological basis. The AP phenotype may be determined by HLA and perhaps other factors in patients otherwise predisposed to PLE.

What is actinic prurigo in Britain?

Actinic prurigo (AP) belongs to the group of idiopathic photodermatoses sharing a predilection for occurring more commonly in females, and there is much controversy as to whether it is only a more severe form of polymorphous light eruption (PMLE) or whether it is a distinct entity in its own right. The condition is characterised by intensely itchy papules, plaques and nodules, along with excoriations and scars usually starting before puberty, and predominantly involves the sun-exposed areas although it may also affect covered sites. Seasonal exacerbations at the beginning of spring with improvement in the fall are typical, although the lesions frequently do not clear completely in the winter. The disorder may run a chronic course and persist into adulthood, but often spontaneous resolution occurs in late adolescence. Diagnosis is predominantly based on the clinical features, cutaneous irradiation tests and histology often being normal or non-specific. HLA typing has also been performed in both PMLE and AP patients, showing a strong association between HLA-DR4, in particular with the DRB1*0407 subtype, and AP; no HLA association has been found in PMLE. This HLA association is likely to be of pathogenic significance and strongly suggests a critical role for MHC-restricted antigen presentation in the development of photosensitivity AP.

Actinic prurigo. The possible etiologic role of an amino acid in the diet

Actinic prurigo is a chronic skin disease commonly associated with cheilitis and conjunctivitis. This peculiar disorder, with ethnic, genetic, environmental, clinical and histological features, represents an abnormal reaction to sunlight. It occurs in American Indians of Canada, United States and most frequently in Latin America where it involves not only indigents but also the mixed ancestry (Mestizo) population. In analogy to what is well known about pellagra, a disease also with solar influence and a deficient intake of tryptophan or niacin in diet, it is our hypothesis that actinic prurigo patients develop their disease due to, among other factors, a diet poor in proteins.

HLA typing in actinic prurigo

Thirty-two actinic prurigo patients of Cree ancestry underwent human lymphocyte antigen (HLA) typing and were compared with 32 control subjects of Cree ancestry. We found a significantly increased frequency of HLA-A24 and Cw4 antigens and a significant decrease in the frequency of the A3 antigen in actinic prurigo patients. These HLA associations may be helpful in determining whether actinic prurigo is a distinct disease or a variant of polymorphous light eruption.