UBE2L3 Reduces TRIM21 Expression and IL-1ß Secretion in Epidermal Keratinocytes and Improves Psoriasis-Like Skin.

Proinflammatory cytokines, such as IL-1ß, are important mediators of psoriasis. UBE2L3, an E2 enzyme, is thought to be an indirect target of IL-1ß secretion by binding to ubiquitin ligases such as TRIM21. However, its role in psoriasis remains unknown. In this study, we found that UBE2L3 expression was decreased in psoriatic epidermis, whereas caspase 1 and IL-1ß signaling were strongly activated. When normal human epidermal keratinocytes were stimulated with nigericin, adenosine triphosphate, and poly(dA:dT), downregulation of UBE2L3 and increased secretion of IL-1ß were observed. Treatment with a caspase 1 inhibitor reversed the decrease in the level of UBE2L3. In addition, UBE2L3 overexpression reduced TRIM21, decreased signal transducer and activator of transcription 3 pathway activity, and reduced the level of the IL-1ß precursor (pro‒IL-1ß). Consistently, silencing UBE2L3 enhanced TRIM21 expression, signal transducer and activator of transcription 3 activation, and pro‒IL-1ß production. Finally, in an imiquimod-induced mouse model, UBE2L3 reduction and caspase 1 activation were localized in the epidermis, whereas overexpression of UBE2L3 ameliorated psoriasis-like lesions and reduced pro‒IL-1ß and mature IL-1ß levels in the epidermis. Thus, UBE2L3 may be a protective biomarker that regulates IL-1ß and inhibits TRIM21 in the epidermis of psoriasis.

Mupirocin blocks imiquimod-induced psoriasis-like skin lesion by inhibiting epidermal isoleucyl-tRNA synthetase.

BACKGROUND: The Isoleucyl-tRNA synthetase (IARS) catalyzes isoleucine to the corresponding tRNA, maintaining the accuracy of gene translation. Its role in psoriasis has been not investigated so far. In this study, we aimed to investigate the mechanisms underlying the efficacy of IARS inhibitor, mupirocin, treatment for psoriasis. METHODS: The expression of IARS was determined by immunofluorescence, Western blot and qRT-PCR in normal healthy control- and psoriatic human skin. An imiquimod (IMQ) -induced psoriasis-like skin disease model was used to study the phenotypes changed by an IARS inhibitor, mupirocin (MUP). Endotypes were analyzed by RNA-seq, R&D Luminex multi-factor technique, ELISA, immunofluorescence and flow cytometry. Additionally, the effect of MUP on epidermal keratinocytes (KCs) were conducted in-vitro in primary cultured human KCs. RESULTS: We found the expression of IARS was higher in psoriatic skin than in healthy controls. In IMQ-induced psoriasis-like C57BL/6 J mouse model, MUP reversed IMQ-induced keratinocytes proliferation, expression of inflammatory cytokines and infiltration of immune cells. Furthermore, in cultured human keratinocytes, MUP inhibited proliferation, but promoted apoptosis, which may be related with STAT3 signaling pathway. CONCLUSION: Our finding of blocking the infiltration of immune cells by inhibiting the formation of IARS, could be one mechanism to explain the effect of MUP in the treatment of psoriasis. Developing strategies targeting suppression IARS should open new perspectives for the treatment of psoriasis. Video Abstract.

Sprouty1 exerts a preventive effect on the initiation of psoriasis by inhibiting innate immune antimicrobial peptide cathelicidin and immunocytes.

OBJECTIVES: Psoriasis is an immune-mediated skin disease dominated by the cutaneous immune system. Keratinocytes have been considered important triggers that initiate psoriasis. The key molecules and events of keratinocytes that link the innate immune system in psoriasis must be investigated in more detail. Human psoriasis skin and primary human keratinocyte were detected in vitro. Epidermis specific transgenic mouse strain (Krt14-Sprouty1 tg) was used to further investigate psoriasis-like skin inflammation in vivo. MATERIALS AND METHODS: Bulk RNA sequencing of primary human keratinocyte screened differentially expressed genes, which was confirmed by quantitative real time PCR and Western Blot (WB). Moreover, we concomitantly reviewed open-accessed published RNAseq datasets of human psoriatic skin from GEO database. Immunohistochemical staining and immunofluorescence were used to detect Sprouty1 (SPRY1) expression in human psoriatic skin with and without anti-psoriasis treatments. Krt14-Sprouty1 tg was used to further investigate psoriasis-like skin inflammation, and followed by Hematoxylin and Eosin (HE) Staining, enzyme linked immunosorbent assay (ELISA), Western Blot and flow cytometry. RESULTS: Our data showed that Sprouty1 was decreased in psoriatic skin and keratinocytes. In imiquimod-induced psoriasis-like skin inflammation, the production of cathelicidin (camp/LL37) was inhibited by suppressing signal transducer and activator of transcription3 (Stat3) activation when Sprouty1 overexpressed in mouse epidermal keratinocytes. Moreover, CD11b+CCR2+ dendritic cells, IL-17A+ γδT cells, and Ly6C+ CD11c+ monocyte-derived dendritic cells were decreased in Krt14-Sprouty1 tg (STG) imiquimod-induced cutaneous inflammation. CONCLUSIONS: These findings indicate that Sprouty1 expressed in keratinocytes has a suppressive role in imiquimod-induced skin inflammation mediated by inhibiting the production of cathelicidin. Collectively, Sprouty1 plays a preventive role in psoriatic skin. Our data provide new evidence for the pathogenesis of psoriatic keratinocytes, and the link cutaneous innate immunity, that indicated Sprouty1 is a potential novel therapeutic target.

Long-Term Treatment with Dimethyl Fumarate for Plaque Psoriasis in Routine Practice: Good Overall Effectiveness and Positive Effect on Impactful Areas.

INTRODUCTION: Dimethyl fumarate (DMF) is an oral compound to treat plaque psoriasis. Data on the treatment of patients with psoriasis affecting impactful areas are scarce. In this interim analysis of the prospective, noninterventional SKILL study, we summarized results of DMF treatment regarding effectiveness (overall and in impactful areas) and safety. METHODS: Data from 676 patients suffering from moderate-to-severe plaque psoriasis were analyzed after 52 weeks of DMF treatment. Of these, 257 had data available after 52 weeks. The considered impactful areas were nails, palms, soles, and scalp. Data analysis included observed cases (OC) and last observation carried forward (LOCF). RESULTS: All effectiveness parameters improved after 52 weeks. The Psoriasis Area and Severity Index score was reduced by 79.5% (OC) and 65.7% (LOCF). Compared with baseline, improvements were shown for 70.2% of the patients in their nail psoriasis [nail-Physician Global Assessment (PGA)] and for 57.3% in palmoplantar disease (palmoplantar-PGA). The proportion of patients with scalp-PGA 0/1 (clear/almost clear) increased significantly to 79.8% (OC) and 69.3% (LOCF, both p < 0.001) (versus 37.5% and 36.6% at baseline, respectively). Significant reduction of pruritus (p < 0.001) was also observed. No unexpected adverse drug reactions were observed. CONCLUSION: Long-term treatment with DMF in routine practice showed good overall effectiveness and safety, and a positive effect on plaque-psoriasis-affected impactful areas.

Immunotherapy in psoriasis.

Over the past two decades, significant progress has been achieved in the treatment of psoriasis by targeting the human cytokine network. At present, 11 biologicals - antibodies, and a soluble receptor - are used to neutralize key inflammatory cytokines. Based on their targets, they can be grouped into the following four classes: TNF-α-, IL-12/23-, IL-17- and IL-23-inhibitors. The range of available substances, as well as their different modes of action can be challenging when selecting the right drug for an individual patient. In this article, we provide an overview of the approved biologicals for the treatment of psoriasis, including their advantages and limitations, and summarize criteria for therapy selection.

Quantitative Proteomic Profile of Psoriatic Epidermis Identifies OAS2 as a Novel Biomarker for Disease Activity.

Psoriasis is a common chronic inflammatory systemic disease. Epidermal proteins are considered to be important in maintaining skin barrier function, innate immunity, and inflammation. To define more possible roles of the epidermis in the pathogenesis of psoriasis, quantified proteomic analysis was used to screen and analyze the differentially expressed epidermal proteins between 16 psoriasis patients and 15 healthy controls. Upregulated differential expression proteins (DEPs) include several significant functional protein clusters, including antimicrobial peptides (AMPs) and antiviral proteins (AVPs). The levels of 2-5-oligoadenylate synthase 2 (OAS2) in both epidermis and serum levels were significantly elevated in psoriasis and were also positively correlated with Psoriasis Area Severity Index (PASI) scores and Body Surface Area (BSA) scores. Moreover, OAS2 expression in psoriatic skin significantly decreased after IL-17R mono-antibody treatment. It has been clarified that inflamed keratinocytes were the main source of abnormally increased OAS2 in psoriasis skin by immunofluorescence and primary cell cultures. Keratinocyte-derived OAS2 can be induced by not only IFNß, but also psoriasis associated cytokines like IL-17A and IL-6. This study revealed that AMPs and AVPs are two important functional protein clusters altering innate immune in psoriatic epidermis. OAS2 is a novel potential sensitive biomarker, which could predict the severity and activity of psoriasis, and could also be used as an indicator to evaluate or monitor the efficacy of clinical treatment.

Suppressor of Fused Inhibits Skin Wound Healing.

Objectives: To investigate the effect of suppressor of fused (Sufu) on epidermal and dermal cellular properties and in wound healing. Approach: Transgenic (TG) mice overexpressing human Sufu (hSufu) in the epidermis were applied to investigate the effects of Sufu on epidermal and dermal cellular properties and in wound healing. Results: Histological staining revealed a reduction of epidermal and dermal thickness and an increase of hypodermal adipose tissue in homozygous K14-hSufu TG mice when compared with wild-type (WT) controls. TG mice exhibited significantly delayed skin wound healing. Moreover, the migratory and proliferative capabilities of cultured keratinocytes were decreased in K14-hSufuTG mice. Transforming growth factor-ß treatment increased the expression of α-smooth muscle actin more in WT than in TG fibroblasts. Sufu overexpression significantly decreased the expression of ß-catenin, glioma transcription factor 1 (Gli1), and matrix metalloproteinase-3 in wounds of K14-hSufu TG mice when compared with controls, probably indicating a delaying effect of Sufu on wound healing via blocking the hedgehog (Hh)/Gli and Wnt/ß-catenin pathway. Innovation: Our results indicate a new property of Sufu in the process of skin wound healing. It provides an important basis for Sufu as a potential target for skin wound healing. Conclusion: Our findings suggest that Sufu overexpression in the epidermis impairs wound healing via dampening the Hh/Gli and Wnt/ß-catenin signaling pathway. These data provide an important basis for further analyses of Sufu in skin wound healing.

The role of Sprouty1 in the proliferation, differentiation and apoptosis of epidermal keratinocytes.

OBJECTIVES: Sprouty (SPRY) 1 is one of the SPRY proteins that inhibits signalling from various growth factors pathways and has also been known as a tumour suppressor in various malignancies. However, no study elucidates the role of SPRY1 in the skin. Our study was conducted to determine the function of SPRY1 in human keratinocytes and the epidermis. MATERIALS AND METHODS: In vitro primary cultured epidermal keratinocytes were used to investigate the proliferation, differentiation and apoptosis of these cells. We also established overexpression of SPRY1 in vitro and K14-SPRY1 transgenic mice. RESULTS: SPRY1 was mainly located in the cytoplasm of the epidermal keratinocytes from the granular epidermal layer of the skin and cultured cells. Overexpressed SPRY1 in keratinocytes resulted in up-regulation of P21, P27 and down-regulation of cyclin B1; decrease in MMP3 and integrin α6. SPRY1-overexpressed primary keratinocytes exhibited a lower proliferation and migration capability and higher rates of apoptosis. Epidermis of SPRY1-TG mice represented delayed wound healing. Proteomics analysis and GO enrichment showed DEPs of SPRY1 TG mice epidermis is significantly enriched in immune- and inflammatory-associated biological process. CONCLUSIONS: In summary, SPRY1 expression was inversely correlated with cell proliferation, migration and promote cell apoptosis of keratinocytes. SPRY1 maybe a negative feedback regulator in normal human epidermal keratinocytes and cutaneous inflammatory responses. Our study raised the possibility that enhancing expression of SPRY1 may have the potential to promote anti-inflammatory effects.

Dimethyl fumarate (DMF) vs. monoethyl fumarate (MEF) salts for the treatment of plaque psoriasis: a review of clinical data.

Fumarates (fumaric acid esters, FAEs) are orally administered systemic agents used for the treatment of psoriasis and multiple sclerosis. In 1994, a proprietary combination of FAEs was licensed for psoriasis by the German Drug Administration for use within Germany. Since then, fumarates have been established as one of the most commonly used treatments for moderate-to-severe psoriasis in Germany and other countries. The licensed FAE formulation contains dimethyl fumarate (DMF), as well as calcium, zinc, and magnesium salts of monoethyl fumarate (MEF). While the clinical efficacy of this FAE mixture is well established, the combination of esters on which it is based, and its dosing regimen, was determined empirically. Since the mid-1990s, the modes of action and contribution of the different FAEs to their overall therapeutic effect in psoriasis, as well as their adverse event profile, have been investigated in more detail. In this article, the available clinical data for DMF are reviewed and compared with data for the other FAEs. The current evidence substantiates that DMF is the main active compound, via its metabolic transformation to monomethyl fumarate (MMF). A recent phase III randomized and placebo-controlled trial including more than 700 patients demonstrated therapeutic equivalence when comparing the licensed FAE combination with DMF alone, in terms of psoriasis clearance according to the Psoriasis Area and Severity Index (PASI) and Physician's Global Assessment (PGA). Thus, DMF as monotherapy for the treatment of psoriasis is as efficacious as in combination with MEF, making the addition of such fumarate derivatives unnecessary.

Rottlerin as a therapeutic approach in psoriasis: Evidence from in vitro and in vivo studies.

Rottlerin is a natural polyphenolic compound that was initially indicated as a PKCδ inhibitor. However, it was recently revealed that it may target a number of molecules and have biological effects on various cell types and is considered as a possible agent for tumor and cell proliferative diseases. Psoriasis is a chronic inflammatory cutaneous disorder with undefined etiology and is characterized by abnormal cellular proliferation, angiogenesis, and inflammation. Therefore, this paper investigates the regulatory effects of rottlerin on normal human epidermal keratinocytes (NHEKs) and imiquimod (IMQ)-induced psoriasiform (IPI) lesions. In vitro results showed that rottlerin inhibited cell proliferation in NHEKs through growth arrest and NFκB inhibition. It may also induce apoptosis in an autophagy-dependent pathway. We found that rottlerin inhibited human microvascular endothelial cells tube formation on matrigel. Rottlerin also decreased the cell senescence of keratinocytes and intracellular ROS generation, which indicated its antioxidant effect. We also showed that rottlerin affects the expression of keratinocyte proliferation biomarkers. In 12-O-tetradecanoylphorbol13-acetate (TPA)-induced keratinocytes, rottlerin significantly inhibited the expression of the induced pro-inflammatory cytokines in keratinocytes. An animal experiment provided the corresponding evidence based on this evidence in vitro, by using IPI model, we found that rottlerin could relieve the psoriasiform of BALB/c mice by inhibiting keratinocyte proliferation, inflammatory cell infiltration, and vascular proliferation. In conclusion, our results suggest that rottlerin may prove useful in the development of therapeutic agents against psoriasis. However, the deep mechanism still requires further study.

Role of keratin 24 in human epidermal keratinocytes.

Keratin 24 (K24) is a new kind of keratin genes, which encodes a novel keratin protein, K24 that bears high similarity to the type I keratins and displays a unique expression profile. However, the role of K24 is incompletely understood. In our study, we investigated the localization of K24 within the epidermis and possible functions. Keratin 24 was found to be modestly overexpressed in senescent keratinocytes and was mainly restricted to the upper stratum spinosum of epidermis. The protein was required for terminal differentiation upon CaCl2-induced differentiation. In vitro results showed that increased K24 in keratinocytes dramatically changed the differentiation of primary keratinocytes. It also inhibited cell survival by G1/S phase cell cycle arrest and induced senescence, autophagy and apoptosis of keratinocytes. In addition, K24 activated PKCδ signal pathway involving in cellular survival. In summary, K24 may be suggested as a potential differentiation marker and anti-proliferative factor in the epidermis.

Inhibition of the hedgehog pathway leads to antifibrotic effects in dermal fibrosis.

Dermal fibrosis is characterized by the activation of the matrix-producing 'positive' myofibroblasts, and the relentless production and deposition of extracellular matrix. The hedgehog pathway has recently been demonstrated to work in a pro-fibrotic manner in systemic sclerosis (SSc). A negative regulator of the hedgehog pathway (Hh), the suppressor of fused (Sufu), was shown to be involved in the activation of fibrotic diseases. However, the exact role of Sufu in fibrosis has not been investigated so far. In our study, we aimed to define the role of sufu in the process of fibrosis using dermal fibroblasts of healthy donors that were cultured in vitro. Cyclopamine, a Smo antagonist, and Sufu lentivector were used to treat or transfect cells. The expression of fibrosis markers and ERK1/2, Smad2, and GSK3ß at the protein level was determined by Western blot. Fibroblast migration was measured by in vitro wound healing assay. Bleomycin-induced dermal fibrosis mouse model was introduced to assess the effect of cyclopamine on dermal fibrosis in vivo. We found that cyclopamine significantly upregulated the expression of Sufu. Both cyclopamine and Sufu lentivector reduced migration and myofibroblast differentiation of human dermal fibroblasts at a statistically significant level. Furthermore, cyclopamine reversed dermal fibrosis induced by TGF-ß1. Cyclopamine and the overexpression of Sufu inhibited the phosphorylation of GSK-3ß and restrained the migration of fibroblasts. Dermal fibrosis was inhibited by intraperitoneal injection of cyclopamine in a mouse model of scleroderma. Our findings suggest that cyclopamine and Sufu-overexpression may effectively inhibit the endogenous as well as the TGF-ß1-induced activation of fibroblasts through subsequent activation of GSK-3ß. Sufu agonists may be a promising approach in the development of antifibrotic medications for dermal fibrosis and systemic sclerosis.

The effect of epidermal levels of urocanic acid on 25-hydroxyvitamin D synthesis and inflammatory mediators upon narrowband UVB irradiation.

BACKGROUND/PURPOSE: Urocanic acid (UCA) absorbs ultraviolet (UV)B radiation in the epidermis which may interfere with phototherapy. Therefore, the influence of individual levels of UCA on immune reactivity and vitamin D synthesis induced by narrowband UVB radiation was assessed. METHODS: Twenty-eight subjects with irritant contact dermatitis of the hands were irradiated with suberythemal doses of narrowband UVB radiation on their unaffected lower forearms on three consecutive days. Stratum corneum tape strips and epidermal interstitial fluid (ISF) as well as blood samples were analyzed. RESULTS: Narrowband UVB irradiation led to the conversion of trans-UCA into its cis-isomer in the epidermis. The observed increase in 25-hydroxyvitamin D serum concentrations was inversely correlated with the baseline levels of trans-UCA. Furthermore, UVB irradiation induced significant changes in the levels of CXCL10/IP-10, CCL2/MCP-1, CCL4/MIP-1ß, and the IL-1RA/IL-1α ratio. The levels of IL-1α and CXCL9/MIG showed a trend toward increase. The changes in the levels of inflammatory and immunomodulatory mediators did not depend on baseline levels of trans-UCA. CONCLUSION: The results suggest that epidermal levels of trans-UCA affect vitamin D synthesis, but not cutaneous immune reactivity upon repeated exposure to suberythemal doses of narrowband UVB radiation. However, this requires further exploration.

Biomarkers and personalized medicine: current status and further perspectives with special focus on dermatology.

Biomarkers are of increasingly high importance in medicine, particularly in the realm of 'personalized medicine'. They are valuable for predicting prognosis and dose selection. Moreover, they may be helpful in detecting therapeutic and adverse responses and in patient stratification based on efficacy or safety prediction. Thus, biomarkers are essential tools for the selection of appropriate patients for treatment with certain drugs to and enable personalized medicine, that is 'providing the right treatment to the right patient, at the right dose at the right time'. Currently, there are six drugs approved for dermatological indications with recommended or mandatory biomarker testing. Most of them are used to treat melanoma and human immunodeficiency virus infection. In contrast to the few fully validated biomarkers, many exploratory biomarkers and biomarker candidates have potential applications. Prognostic biomarkers are of particular significance for malignant conditions. Similarly, diagnostic biomarkers are important in autoimmune diseases. Disease severity biomarkers are helpful tools in the treatment for inflammatory skin diseases. Identification, qualification and implementation of the different kinds of biomarkers are challenging and frequently necessitate collaborative efforts. This is particularly true for stratification biomarkers that require a companion diagnostic marker that is co-developed with a certain drug. In this article general definitions and requirements for biomarkers as well as for the impact of biomarkers in dermatology are reviewed and opportunities and challenges are discussed.

Industry-academia collaborations for biomarkers.

Several types of collaboration are being pursued to identify, validate and apply new biomarkers. Here, we highlight examples of such initiatives and discuss the challenges, approaches to address these challenges and key factors for success.

Analysis of epithelial-mesenchymal transition markers in psoriatic epidermal keratinocytes.

Psoriasis is similar to endpoints of epithelial-mesenchymal transition (EMT), a process of epithelial cells transformed into fibroblast-like cells. The molecular epithelial and mesenchymal markers were analysed in psoriatic keratinocytes. No obvious alteration of epithelial markers E-cadherin (E-cad), keratin 10 (K10), K14 and K16 was detected in psoriatic keratinocytes. However, significantly increased expression of Vim, FN, plasminogen activator inhibitor 1 (PAI-1) and Slug was seen. IL-17A and IL-13 at 50 ng ml(-1) strongly decreased expression of K10, Vim and FN. TGF-ß1 at 50 ng ml(-1) promoted the production of N-cad, Vim, FN and PAI-1. Slug was decreased by dexamethasone (Dex), but E-cad was upregulated by Dex. Silencing of ERK partially increased E-cad and K16, but remarkably inhibited K14, FN, Vim, ß-catenin, Slug and α5 integrin. Moreover, inhibition of Rho and GSK3 by their inhibitors Y27632 and SB216763, respectively, strongly raised E-cad, ß-catenin and Slug. Dex decreased Y27632-mediated increase of ß-catenin. Dex at 2.0 µM inhibited SB216763-regulated E-cad, ß-catenin and slug. In conclusion, EMT in psoriatic keratinocytes may be defined as an intermediate phenotype of type 2 EMT. ERK, Rho and GSK3 play active roles in the process of EMT in psoriatic keratinocytes.

Handling chemotherapy drugs-Do medical gloves really protect?

Due to their potential mutagenic, carcinogenic and teratogenic effects occupational exposure to chemotherapy drugs should be kept to a minimum. Utilization of personnel protective devices, especially the use of protective medical gloves, is a mainstay to avoid skin contact. The choice of appropriate gloves is of outstanding importance. For optimal protection in the oncology setting it is essential to establish general guidelines evaluating appropriate materials and defining quality standards. Establishing these guidelines can facilitate better handling and avoid potential hazards and late sequelae. In Europe there are no specific requirements or test methodologies for medical gloves used in the oncology environment. The implementation of uniform standards for gloves used while handling chemotherapy drugs would be desirable. In contrast, in the US medical gloves used to handle chemotherapy drugs have to fulfill requirements according to the ASTM International (American Society of Testing and Materials) standard D 6978-05. Nitrile or natural rubber latex is a preferred basic glove material, while vinyl is considered inappropriate because of its generally increased permeability. For extended exposure to chemotherapy drugs, double gloving, the use of thicker gloves and the frequent change of gloves increases their protective power.

No remarkable differences in rates of sensitization to common type I and IV allergens between FLG loss-of-function mutation carriers and wild-type subjects.

BACKGROUND: Loss-of-function mutations in the filaggrin gene (FLG) have been associated with reduced skin barrier function, possibly allowing increased penetration of irritants and allergens. OBJECTIVES: To study whether FLG loss-of-function mutation carriers show different rates of sensitization to common type I and IV allergens among patients referred for occupational contact dermatitis of the hands. MATERIALS AND METHODS: Four hundred and ninety-six Caucasian patients were genotyped for four FLG null mutations and patch tested with the European baseline series. In addition, 431 patients underwent prick testing with common type I allergens. RESULTS: Overall, 67 patients showed a heterozygous mutation in the FLG alleles R501X, R2447X, S3247X, and/or 2282del4. Sensitization rates for type I allergens from a European prick test series did not show significant differences between FLG loss-of-function mutation carriers and wild-type subjects. For type IV allergens, significantly more FLG loss-of-function carriers were found to be sensitized to lanolin and p-tert-butylphenol-formaldehyde resin. CONCLUSIONS: Probably a variety of immunological mechanisms other than that resulting from the filaggrin system have an impact on allergic sensitization to a greater degree. Larger cohorts may be necessary to increase the statistical power of the findings presented regarding type I and IV sensitization.

Topical ophthalmic agents as allergens in periorbital dermatitis.

BACKGROUND: Allergic contact dermatitis is a leading cause of periorbital dermatitis. The extremely thin nature of the periorbital skin may facilitate allergen penetration, making this area particularly susceptible to allergic contact sensitisation. In this study, we assessed sensitisation rates to ingredients of common topical ophthalmic agents. MATERIALS AND METHODS: Data collected by 57 participating centres of the Information Network of Departments of Dermatology (IVDK) were analysed retrospectively. Of the 101,403 patients patch tested between January 2001 and December 2010, 4779 patients suffered from periorbital dermatitis and 1158 patients were specifically tested to the ophthalmic tray. Patch test results of the latter group were analysed in detail. RESULTS: The ophthalmic tray consisted of seven preservatives, six antibiotics and three other ophthalmic agents. Antibiotics (gentamicin, neomycin, kanamycin) were the leading group of allergens. Patch testing with preservatives often elicited irritant or weak positive reactions. CONCLUSIONS: When suspecting contact allergy in the periorbital area, patch testing should be considered in order to identify and avoid offending allergens. Testing to substances from a standardised ophthalmic tray is recommended, but it is preferable to test the actual drops or creams since many chemicals that are present in ophthalmics are not available as commercial test allergens. Given their wide use, preservatives cannot be regarded as common allergens, while antibiotics cause more often true allergic reactions necessitating a long-term avoidance.