The idiopathic photodermatoses

Recent Developments in the Diagnosis and Management of Photosensitive Disorders

Photodermatoses occur in males and females of all races and ages. Onset can be variable in timing and influenced by genetic and environmental factors. Photodermatoses are broadly classified as immunologically mediated, chemical- and drug-induced, photoaggravated, and genetic (defective DNA repair or chromosomal instability) diseases. Advances in the field have led to improved recognition and treatment of many photodermatoses. The purpose of this focused review is to provide an update on the diagnosis and management of a variety of photodermatoses, both common and less common, with review of recent updates in the literature pertaining to their diagnosis and management.

Clinicopathological features of pediatric renal biopsies in the plateau regions of China

Objective

This study aimed to analyze the clinicopathological features of pediatric renal biopsies from plateau regions of China.

Methods

Clinicopathological features of pediatric renal biopsies were compared between plateau and non-plateau regions in patients who were admitted to West China Second University Hospital, Sichuan University between April 2001 and March 2017. Patients were children younger than 18 years.

Results

The proportion of primary glomerular disease in the plateau group was lower than that in the non-plateau group (45.56% vs 62.09%, respectively). In the plateau group, IgA nephropathy (IgAN) was the major primary glomerulonephritis (GN) pathology. IgAN accounted for 36.54% and 21.63% of GN cases with nephrotic syndrome and hematuria, respectively. Henoch-Schönlein purpura nephritis was the most common secondary GN in both groups. The proportion of hepatitis B virus-associated GN was higher and that of lupus nephritis was lower in the plateau group than in the non-plateau group.

Conclusions

There are differences in renal pathological types between children in plateau regions and those in non-plateau regions. Among children in plateau regions, IgAN and Henoch-Schönlein purpura nephritis were the most common kidney diseases.

Unique profile of antimicrobial peptide expression in polymorphic light eruption lesions compared to healthy skin, atopic dermatitis, and psoriasis

Background

Polymorphic light eruption (PLE) has been attributed to type IV, most likely delayed‐type hypersensitivity response (adaptive immunity) but little is known on innate immunity, especially antimicrobial peptides (AMPs) in the disease. Abnormalities in AMP expression have been linked to pathological skin conditions such as atopic dermatitis (AD) and psoriasis.

Methods

Antimicrobial peptide profiling was carried out in PLE skin samples (n,12) compared with that of healthy (n,13), atopic (n,6), and psoriatic skin (n,6).

Results

Compared to healthy skin, we observed increased expression of psoriasin and RNAse7 (both mostly in stratum granulosum of the epidermis), HBD‐2 (in the cellular infiltrate of the dermis), and LL37 (mostly in and around blood vessels and glands) in PLE lesional skin, a similar expression profile as present in psoriatic skin and different to that of AD (with little or no expression of psoriasin, RNAse7, HBD‐2, and LL37). HBD‐3 was downregulated in PLE compared to its high expression in the epidermis and dermis of healthy skin, AD, and psoriasis.

Conclusion

The unique profile of differentially expressed AMPs in PLE implies a role in the pathophysiology of the disease, possibly directly or indirectly linked to the microbiome of the skin.

Disorders characterized by predominant or exclusive dermal inflammation

Some cutaneous inflammatory disorders are typified by a predominant or exclusive localization in the dermis. They can be further subdivided by the principal cell types into lymphocytic, neutrophilic, and eosinophilic infiltrates, and mixtures of them are also seen in a proportion of cases. This review considers such conditions. Included among the lymphoid lesions are viral exanthems, pigmented purpuras, gyrate erythemas, polymorphous light eruption, lupus tumidus, and cutaneous lymphoid hyperplasia. Neutrophilic infiltrates are represented by infections, Sweet syndrome, pyoderma gangrenosum, and hidradenitis suppurativa, as well as a group of so-called "autoinflammatory" dermatitides comprising polymorphonuclear leukocytes. Eosinophil-dominated lesions include arthropod bite reactions, cutaneous parasitic infestations, the urticarial phase of bullous pemphigoid, Wells syndrome (eosinophilic cellulitis), hypereosinophilic syndrome, and Churg-Strauss disease. In other conditions, eosinophils are admixed with neutrophils in the corium, with or without small-vessel vasculitis. Exemplary disorders with those patterns include drug eruptions, chronic idiopathic urticaria, urticarial vasculitis, granuloma faciale, and Schnitzler syndrome (chronic urticarial with a monoclonal gammopathy).

Influence of the season on vitamin D levels and regulatory T cells in patients with polymorphic light eruption

The exact mechanisms of photohardening in polymorphic light eruption (PLE) are still unknown, but medical photohardening was shown to increase regulatory T cell (Treg) numbers in the blood of PLE patients, similar to natural hardening. Furthermore, oral vitamin D supplementation increased peripheral Tregs in healthy individuals. We herein report on a post hoc analysis of 26 screened PLE patients of a clinical trial (ClinicalTrials.gov No. NCT01595893), in which the influence of the progressing season was investigated on baseline CD4+CD25+FoxP3+CD127- Treg numbers by flow cytometry and Treg suppressive function by co-culture assays with T effector cells as a secondary endpoint, together with 25-hydroxy vitamin D (25(OH)D) serum levels at the study's screening visit, taking place in the period from January to June. The mean 25(OH)D serum level of all patients was 33.2 ng ml(-1). Ten of those patients (38.5%) were identified with low 25(OH)D levels (<30 ng ml(-1)). Significantly higher baseline 25(OH)D serum levels (plus 34.4%; P = 0.0182) as well as higher relative Treg percentages in CD4+ population (plus 62.8%; P = 0.0157) and in total lymphocyte population (plus 59.6%; P = 0.0372) and higher absolute Treg numbers (plus 100.2%; P = 0.0042) were observed in the late spring/early summer period (April to June) compared to the winter period (January to February). No significant relationship was observed when Treg numbers and function were correlated with 25(OH)D levels. These data indicate that in PLE patients Treg numbers and their suppressive function are independent of vitamin D serum levels and suggest that UV light and/or other seasonal factors may affect these cells via the non-vitamin D related pathway(s).

Actinic prurigo

Actinic prurigo is a chronic photodermatosis with onset in childhood or before 20 years of age. It is most prevalent in Amerindians and Latin American mestizos, although it has been reported worldwide. Patients present with photodistributed, erythematous excoriated papules, cheilitis, and conjunctivitis. There is strong association with human leukocyte antigen DR4, especially the DRB1*0407 subtype. Treatment consists of photoprotection and the use of thalidomide.

Polymorphous light eruption: clinic aspects and pathogenesis

Polymorphous light eruption is an immunologically mediated photodermatosis with high prevalence, particularly among young women in temperate climates, characterized by pruritic skin lesions of variable morphology, occurring in spring or early summer on sun-exposed body sites. A resistance to ultraviolet radiation (UVR)-induced immunosuppression and a subsequent delayed-type hypersensitivity response to a photoantigen have been suggested as key factors in the disease. Molecular and immunologic disturbances associated with disease pathogenesis include a failure of skin infiltration by neutrophils and other regulatory immune cells on UVR exposure linked to a disturbed cytokine microenvironment. Standard management is based on prevention.

Systemic lupus erythematosus patients in the low-latitude plateau of China: altitudinal influences

The current study was to investigate the features of hospitalized patients with systemic lupus erythematosus (SLE) at different altitudes. The correlation between SLE activity and altitudinal variations was also explored. Medical records of 1029 patients were retrospectively reviewed. Activity of SLE in each organ system was recorded using the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). There was no significant correlation between SLE activity and altitudes (r = 0.003, p = 0.159). Age at onset for SLE patients at high altitudes was significantly younger than that at low and moderate altitudes (p = 0.022 and p = 0.004, respectively). Age at SLE admission at low altitudes was significant older than those at moderate and high altitudes (p = 0.011 and p < 0.001, respectively). Patients at high altitudes had shorter duration from disease onset to admission than those at moderate altitudes (p = 0.009). Incidence of Sm antibodies-positive for resident patients at high altitudes was 36.4%, which were higher than that at moderate altitudes (p = 0.003). We found increasing trends of CNS activity in active patients; immunological and renal activities in inactive patients were correlated with elevated altitudes (p = 0.024, p = 0.004, p = 0.005), while arthritis scores in active patients showed the tendency of decreasing with the rise of elevation (p = 0.002). Hemoglobin level, red blood cell and platelet counts at high altitudes were significantly lower than those at low altitudes (p < 0.05, respectively). There was no significant difference in hemoglobin level between moderate- and low-altitude groups (p > 0.05). No significant difference in platelet counts between moderate- and high-altitude groups was observed (p > 0.05). Our findings suggest that some clinical features, laboratory tests and activity of main organs in SLE are influenced by altitudes. Furthermore, organ activities of active and inactive SLE patients have different patterns of altitudinal variations. These distinctive variations likely reveal that peculiar environmental factors at high altitudes can affect the development of SLE.

Photodermatoses with onset in the elderly

Photodermatoses are a group of skin disorders induced by ultraviolet radiation (UVR) and, in some cases, visible light. To establish a diagnosis it is important to carefully take a history, physical examination and perform phototesting as well as other testing when appropriate (patch and photopatch tests, antinuclear antibodies, porphyrin profile). This article focuses on the photodermatoses that affect the elderly, which with the ageing of population, particularly in the industrialized societies, are becoming an increasingly important group for the healthcare systems. The most common photodermatoses with onset in the elderly are chronic actinic dermatitis and drug induced photosensitivity.

Prevalence of photodermatosis in four regions at different altitudes in Yunnan province, China

Idiopathic photodermatoses are common diseases in dermatology clinics that are associated with ultraviolet (UV) irradiation. The group includes a few dermatoses such as polymorphous light eruption (PLE) and chronic actinic dermatitis (CAD). The prevalence of PLE and CAD in China has not been previously reported. To investigate the population-based prevalence of polymorphous light eruption (PLE) and chronic actinic dermatitis (CAD) in six minority groups living in four regions with significantly different altitudes in the Yunnan province, a questionnaire survey was administered to 4899 residents of random villages in Yuanjiang county (Dai and Hani minorities), Kunming city (Han people and Yi minority), Lijiang county (Naxi minority), and Shangri-La county (Zang minority). The altitudes of these counties are 380 m, 1870 m, 2410 m and 3280 m a.s.l., respectively. The results showed that, first, there were 2400 males (49.0%) and 2499 females (51.0%). The prevalence of PLE was 0.65% (32/4899), and the prevalence of CAD was 0.18% (9/4899). PLE was higher among females than males (3.8 vs 1, P < 0.01). The CAD prevalence was not significantly different between males and females (1.6 vs 1, P > 0.05). Second, the prevalence of PLE was increased in higher elevations regions compared to lower elevations (P < 0.01). However, the prevalence of CAD was not significantly different among the four regions (P > 0.05). Third, the mean times of sun exposure for PLE and CAD were 6.0 and 6.5 h/day, respectively. The mean durations of PLE and CAD were 5.8 years, and 6.6 years, respectively. The study demonstrated that the prevalence of PLE is higher than that of CAD in Yunnan, and that the prevalence of PLE is correlated with altitude.

Treatment of polymorphic light eruption

Polymorphic light eruption (PLE) is a highly prevalent photosensitivity disorder, estimated to affect 11-21% people in temperate countries. Typically, PLE appears as a recurrent pruritic eruption comprising papules and/or vesicles and/or plaques, which occurs on photo-exposed skin sites following sun exposure, and which heals without scarring. Commoner in females, the aetiology is uncertain, although there is evidence of an immune basis. We perform a review of the prophylaxis and treatment of this condition. While sun protection, corticosteroids and desensitization phototherapy are the mainstays of management, a range of anti-inflammatory and immunomodulatory agents are reported.

Spectrum of idiopathic photodermatoses in a Mediterranean country

BACKGROUND

Idiopathic photodermatoses are considered to be common disorders in the population of northern latitude countries, presumably because of the dominance of more "sun-sensitive" individuals with a light-skinned complexion. The incidence of these disorders in the Mediterranean or tropical countries is often under-appreciated because of the higher degree of perennial presence of sunlight and the prevalence of darker skin-type individuals who are seemingly more resistant to the development of sun sensitivity.

METHODS

We performed a retrospective, chart-based review of all patients who were diagnosed with idiopathic photodermatoses at a photodermatology referral center in Athens, Greece, during a period of 10 years. Our aim was to assess the pattern of idiopathic photosensitivity disorders in a Mediterranean country and to determine their epidemiological, clinical, and photobiological profile.

RESULTS

A total of 310 patients were referred to our center with symptoms of photosensitivity. One hundred and forty-six patients (47.0%) were diagnosed with an idiopathic photosensitivity disorder by means of history, clinical examination, biochemical screening, histology, and phototesting. The most prevalent disorder was polymorphous light eruption, which was diagnosed in 95 patients (65.0%) of our cohort. Chronic actinic dermatitis occurred in 15 patients (10.2%), solar urticaria in 26 patients (17.8%), actinic prurigo in three patients (2.0%), hydroa vacciniforme in one patient (0.6%) and juvenile spring eruption in six patients (4.1%).

CONCLUSIONS

Compared with the results of other studies, the prevalence of idiopathic photodermatoses appears to have a similar trend to that of higher latitude countries. Distinct features in our series include the higher incidence of idiopathic photosensitivity in patients with a fair-skinned complexion (skin types II-III) and the frequent appearance of photo-induced eruptions during sunny weather breaks in the winter period.

Idiopathic photodermatoses: clinical, diagnostic and therapeutic aspects

Idiopathic photodermatoses are a group of photosensitivity dermatoses, which are not very frequent with the exception of polymorphous light eruption. Therefore, their recognition may not be easy for dermatologists who are not familiar with photosensitivity diseases.

LEARNING OBJECTIVE

The information in this review is intended for giving clinical, diagnostic and therapeutic clues for the correct management of patients. Clinical features will be described together with diagnostic relevant procedures and usual therapeutic measures.