Psoriasis in the Tropics: Epidemiologic, Genetic, Clinical, and Therapeutic Aspects

A systematic review and meta-analysis of angiotensin-converting enzyme inhibitor use and psoriasis incidence

Although a considerable volume of data supporting induction or aggravation of psoriasis because of angiotensin-converting enzyme (ACE) inhibitor use exists, it remains insufficient for definitive conclusions. Therefore, we aimed to evaluate the association between ACE inhibitor use and psoriasis incidence through a systematic literature review and meta-analysis. We searched for qualifying studies across PubMed, Web of Science, and Embase. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to evaluate the strength of the association between ACE inhibitor use and psoriasis incidence. Eight studies with a total of 54,509 patients with a psoriasis diagnosis were included in this meta-analysis. The pooled OR for psoriasis incidence among ACE inhibitor users was 1.52 (95% CI, 1.16–2.00) compared to that among non-users. From subgroup analysis by continent, the OR for ACE inhibitor users versus non-users was 2.37 (95% CI 1.28–4.37) in Asia. Per the subgroup analysis by climate, the OR for ACE inhibitor users vs non-users in dry climate was 3.45 (95% CI: 2.05–5.79) vs 1.32 (95% CI 1.01–1.73) in temperate climate. Our results reveal a significant association between ACE inhibitor use and psoriasis incidence.

The incidence of psoriasis in Chile: an analysis of the National Waiting List Repository

Background

Psoriasis is a serious and chronic noncommunicable disease. However, the fundamental measure of disease occurrence, the incidence, has been scarcely reported globally. There are no previous studies of psoriasis incidence in Latin America.

Aim

To estimate the incidence rates of psoriasis in Chile during 2016 and 2017 using an administrative database, the Waiting List Repository.

Methods

We examined referrals of psoriasis at onset, made by physicians to dermatologists, evaluated the agreement of diagnosis, and estimated the incidence of the disease considering the eligible population at risk.

Results

In most cases, the referrals corresponded to incident cases of psoriasis (73.3%; 95% CI: 66.6–79.2). The national incidence rates of psoriasis were 22.1 (95% CI: 21.1–23.1) and 22.7 (95% CI: 21.8–23.6) per 100 000 person‐years in 2016 and 2017, respectively. The most common type of psoriasis was the late‐onset type. We observed a high variation in the figures throughout the country, with a range from 0.75 (95% CI: 0.3–1.5) per 100 000 person‐years in the Metropolitan region to 164.9 (95% CI: 138.6–195.1) per 100 000 person‐years in the Aysen region.

Conclusion

We describe for the first time the incidence of psoriasis in a Latin American country. Our findings could potentially guide collaborations to improve our global understanding of psoriasis in Latin America.

Prevalence of Skin Disease in Urban Haiti: A Cross-Sectional Study

The prevalence of skin disease varies with geographic location and may be affected by cultural factors. In Haiti, the combination of poor health care access, infrastructure lack, and natural disasters may affect the prevalence of skin conditions. Unfortunately, little epidemiological information has been obtained on the prevalence of skin diseases in Haiti. The objective of this study is to describe data on the prevalence of dermatological conditions in urban areas of Haiti. Univariate, bivariate, and χ2 analyses were used to evaluate associations. During February 2016, we documented 137 patients. The mean age was 27.7 years; most of the subjects were women (61.3%) in a cohort mostly adult (67.1%). The infectious and inflammatory dermatoses were the most prevalent (74.2%). Infectious skin diseases were more prevalent in men and in adults in general (p < 0.01). Inflammatory conditions were also more common in adults (p < 0.05). Additionally, alopecia and dyschromia were limited to women (p < 0.01). Infectious skin diseases, in particular fungal infections, were amongst the most common diagnoses in the urban area of Haiti. Therefore, improved access to antimicrobial and anti-inflammatory medications would likely benefit Haitian patients with dermatological conditions. These findings may help local public health officials and future dermatological expeditions better serve this population.

HLA-Cw6 and psoriasis

Psoriasis is a multifactorial disease with a strong genetic background. HLA-Cw6 is one of the most strongly associated psoriasis susceptibility alleles. It is repeatedly observed to affect disease course, phenotypic features, severity, comorbidities and treatment outcomes. To the best of our knowledge, the roles of HLA-Cw6 in psoriasis have not yet been thoroughly reviewed. The worldwide frequency of the HLA-Cw6 allele varies greatly, with it being generally higher in white people than in Asians. The allele is associated with type I early-onset psoriasis. Stress, obesity and streptococcal pharyngitis are commonly observed in HLA-Cw6-positive patients. Phenotypically, HLA-Cw6 has been found to be associated with guttate psoriasis. In addition, patients carrying the allele are more likely to have arm, leg and trunk involvement, and the Koebner phenomenon. Patients with psoriatic arthritis with HLA-Cw6 more often have early onset and tend to show cutaneous symptoms before musculoskeletal symptoms. HLA-Cw6-positive patients have been shown in several studies to be more responsive to methotrexate and ustekinumab. However, this difference in ustekinumab efficacy was only moderate in a post-hoc analysis of a pivotal phase III study. HLA-Cw6 positivity also tends to be less frequent in high-need patients who fail conventional therapy. Small studies have also investigated the role of HLA-Cw6 in remission of psoriasis during pregnancy, and with the comorbidities of photosensitivity and atherosclerosis. Given the diverse nature of psoriasis pathogenesis, as well as the difference of HLA-Cw6 positivity in different ethnic groups, more studies are needed to confirm the role of HLA-Cw6 in psoriasis.

Psoriasis and psoriatic arthritis in Peruvian aborigines: a report from the GRAPPA 2011 annual meeting

OBJECTIVE

To determine the presence of psoriasis and psoriatic arthritis (PsA) in aboriginal people living in the Andean Mountains of Peru.

METHODS

Consecutive patients with psoriasis and PsA attending an arthritis clinic in Juliaca, Puno, Peru, located 3824 m above sea level were examined. The CASPAR (ClASsification of Psoriatic ARthritis) criteria were used for classification of PsA. Diagnosis of psoriasis was confirmed by a dermatologist.

RESULTS

Seventeen patients [11 (65%) men and 6 (35%) women] fulfilled classification criteria for PsA; one patient was of European ancestry and is not included in this report. Of the 16 aboriginal patients in this report, 5 were natives of Quechua ancestry and one was native Aymara. At the time of their first clinic visit, no native patient with PsA had a family history of psoriasis or PsA, and all patients exhibited an established disease of long duration and severity. Methotrexate was the drug of choice for all patients; 2 patients are currently receiving biological therapy.

CONCLUSION

Contrary to what has been reported in the literature, both psoriasis and PsA are present in aboriginal people from the Andean Mountains of Peru. More studies are needed to further define the phenotype of these disorders, as well as the pathogenetic role of genetic and environmental factors.

Epidemiologic study of dermatologic disorders among children in South Sinai, Egypt

BACKGROUND

  Few epidemiologic surveys have been carried out to determine the prevalence of skin diseases in the population of Egypt, particularly in the Sinai Peninsula. Thus, the necessity of such research in South Sinai is pressing. This study aimed to determine the prevalence of various skin diseases among children in South Sinai.

METHODS

A community-based protocol was followed. The study included 2194 children of both genders, 18 years of age and younger, and in six different localities within South Sinai. Data were collected by taking a full history and by systemic and dermatologic clinical examination that included the site, severity, distribution, and extent of skin lesions if present. Subjects were surveyed at general morbidity consultations and campaign field visits. The study was conducted from August 2008 to August 2009. Data were tabulated and analyzed statistically using Pearson's chi-squared test. Differences were considered significant at a P-value of < 0.05.

RESULTS

Findings revealed that 71.4% of the studied population had one or more skin diseases. The highest rate of prevalence applied to parasitic skin infestations (pediculosis capitis, 37.6%). Eczema or dermatitis were found in 25.8% of participants. Pityriasis alba occurred at a rate of 18.3% and seborrheic dermatitis at a rate of 6.7%. Xerosis was found in 11.8% of subjects, viral warts in 4.1%, photosensitivity in 4.1%, acne vulgaris in 2.6%, and fungal skin infections in 1.0%. Other skin diseases diagnosed in low numbers in the study children included impetigo, freckles, and scabies. Prevalences of vitiligo and psoriasis were very low (0.18% and 0.05%, respectively).

CONCLUSIONS

Infective parasitic diseases are a major health problem, particularly among younger children and in subjects of low socioeconomic status.

Skin diseases in the Peruvian Amazonia

BACKGROUND

Dermatologic diseases vary widely as a result of geographic location and may be influenced by environmental factors. Aim To determine the epidemiology of dermatological diseases in the Peruvian Amazonia.

METHODS

Transversal and multicentric study, which were carried out during February of 2006, 2007, and 2008 in three regional hospitals in the Peruvian Amazonia. All new patients who were looking for dermatological consultation were included. Univariate/bivariate analysis, chi square, and multinomial logistic regression were used with a confidence level of 95%.

RESULTS

A total of 1602 patients were included. The infectious and parasitic dermatoses were the most prevalent (31.5%). There was a statistically significant association between infections of the skin and subcutaneous tissue in children (P < 0.001). The parasitic dermatoses such as scabiosis, pediculosis, and myiasis were associated with an altitude less than 700 meters above sea level (m.a.s.l.) (P = 0.003, OR = 3.1, CI: 1.5-6.7). On the other hand, radiation-related disorders of the skin and subcutaneous tissue were associated with more than 700 m.a.s.l. (P < 0.01, OR = 2.9, CI: 1.7-4.9).

CONCLUSIONS

Infectious dermatological diseases were the most common diagnoses in the Peruvian Amazonia. In addition, radiation-related disorders of the skin should be addressed for people living/traveling in the rainforest area. These findings may assist in the training of general doctors in diagnosis and treatment of the most common dermatoses in tropical areas. Moreover, this study would be helpful for physicians from developed countries when giving medical advice/attention to travelers or immigrants of tropical areas.

Geoepidemiology and environmental factors of psoriasis and psoriatic arthritis

Psoriasis and Psoriatic Arthritis (PsA) are chronic inflammatory diseases that have a major impact on health. The prevalence and incidence estimates of these two closely related diseases show ethnic and geographic variations, being generally more common in the colder north than in the tropics. In Europe the prevalence of psoriasis varies anywhere from 0.6 to 6.5%. In the USA, the estimated prevalence of diagnosed psoriasis is 3.15%. The prevalence in Africa varies depending on geographic location, being lowest in West Africa. Psoriasis is less prevalent in China and Japan than in Europe, and is entirely absent in natives of the Andean region of South America. There are fewer reports on the incidence of psoriasis, but a recent study from Rochester, USA showed an increasing trend over the last 2 decades. The prevalence of PsA also shows similar variation, being highest in people of European descent and lowest in the Japanese. Although, study methodology and case definition may explain some of the variations, genetic and environmental factors are important. Genetic epidemiologic studies have shown that both diseases have a strong genetic component. The strongest association is with HLA-Cw*06. Associations with a number of genes including IL12B and IL23R have recently been confirmed. Environmental risk factors including streptococcal pharyngitis, stressful life events, low humidity, drugs, HIV infection, trauma, smoking and obesity have been associated with psoriasis and PsA. Here we have reviewed the current literature on the epidemiology and genetics of psoriasis and PsA.

More than skin deep: atherosclerosis as a systemic manifestation of psoriasis

There is now growing evidence that psoriasis, like other inflammatory diseases such as rheumatoid arthritis and systemic lupus erythematosus, is a systemic disorder that is associated with enhanced atherosclerosis and risk of coronary artery disease. Here we summarize the available epidemiological evidence for this association and analyse pathogenic features that are common to psoriasis and atherosclerosis. Further prospective studies are urgently needed to extend knowledge of the risk of cardiovascular morbidity and mortality in patients with psoriasis and to confirm the degree to which treatment of psoriasis reduces this risk. Nevertheless, existing data are sufficient to indicate that severe psoriasis should be more widely recognized as a potential risk factor for cardiovascular disease and should be considered with the established factors when formulating strategies for the management of cardiovascular risk.

Synchronization of oscillations of proliferation of keratinocytes in psoriatic skin by external periodic force: A mathematical model

A mathematical model of mitotic activity of epidermis in normal skin and skin afflicted with psoriasis is presented as a system of two autonomous nonlinear differential equations. Its qualitative analysis was carried out and numerical solutions were obtained at the parameter values corresponding to these states. It was shown that in the norm, a single stable equilibrium of a "focus" type exists in the system; whereas in psoriasis, owing to an increase in the growing fraction, hyperproliferation, and enhanced migration of interacting keratinocytes, a stable limit cycle arises from the state of unstable focus. In this paper we also report on the results of computer modeling of synchronization of self-excited oscillations of keratinocyte population density in psoriatic lesions by an external periodic force. This synchronization is viewed as a possible mechanism of the clinically observed dependence of psoriasis course on some natural factors of cyclic nature.

Prevalence of skin diseases in rural areas of Assiut Governorate, Upper Egypt

BACKGROUND

Few epidemiological surveys have been carried out to determine the prevalence of skin diseases in the population of Egypt, particularly "Upper Egypt". So it is a pressing necessity to conduct such a study in rural Assiut.

OBJECTIVES

To determine the prevalence of various skin diseases in rural Assiut.

SUBJECTS AND METHODS

A cross-sectional community-based survey was followed. The survey included 8008 rural inhabitants of all ages and both sexes from a representative of three villages of Assiut Governorate, Upper Egypt. The data were collected through personal interview and examination at homes from December 1994 to December 1996.

RESULTS

They showed that 6961 (86.93%) of the studied population had one or more skin diseases. The group with parasitic skin infestations had the highest prevalence rate (27.40%) of the total sample, of which pediculosis capitis (19.37%) was the commonest. Eczema/dermatitis group had a rate of 19.82%, with pityriasis alba forming the majority (13.49%). Pigmentary disorders were 17.68%, followed by fungal skin infections (16.17%), then naevoid disorders (16.10%), hair and scalp disorders (12.07%), bacterial skin infections (10.10%), sweat gland disorders (6.16%), acne vulgaris (5.37%). Leprosy constituted 1.6/10,000. Other various skin disorders were recorded.

CONCLUSIONS

Infective-parasitic diseases were a major problem particularly among the younger age-group and those of low socio-economic status.