Allergic conjunctivitis: an update on diagnosis and management

Secondhand smoke exposure and ocular health: A systematic review

The toxicology of secondhand smoke (SHS), along with the harm of its exposure to human health, has been generally acknowledged; however, specific evidence is lacking on the association between SHS exposure and ocular health. In this systematic review (PROSPERO registration number: CRD42022247992), we included 55 original articles published by 12 May 2023, which dealt with SHS exposure and ocular disorders, such as eye irritation, conjunctivitis, dry eye diseases, uveitis, myopia, astigmatism, contact lens discomfort, age-related macular degeneration, glaucoma, and thyroid eye disease that addressed the ocular neurovascular structures of the macular, retinal nerve fiber layer, choroid, and corneal biomechanical parameters. We found compelling correlational evidence for eye irritation, conjunctivitis, and dry eye symptoms-supporting that SHS exposure was positively associated with inflammatory and allergic changes in the eyes. Yet, evidence about the associations between SHS exposure and other ocular disorders, structures, and parameters is still limited or controversial. Given the limitations of existing literature, more investigations with high quality and rigorous design are warranted to elucidate the potentially harmful effects of SHS exposure on ocular health.

TFOS Lifestyle Report: Impact of environmental conditions on the ocular surface

Environmental risk factors that have an impact on the ocular surface were reviewed and associations with age and sex, race/ethnicity, geographical area, seasonality, prevalence and possible interactions between risk factors are reviewed. Environmental factors can be (a) climate-related: temperature, humidity, wind speed, altitude, dew point, ultraviolet light, and allergen or (b) outdoor and indoor pollution: gases, particulate matter, and other sources of airborne pollutants. Temperature affects ocular surface homeostasis directly and indirectly, precipitating ocular surface diseases and/or symptoms, including trachoma. Humidity is negatively associated with dry eye disease. There is little data on wind speed and dewpoint. High altitude and ultraviolet light exposure are associated with pterygium, ocular surface degenerations and neoplastic disease. Pollution is associated with dry eye disease and conjunctivitis. Primary Sjögren syndrome is associated with exposure to chemical solvents. Living within a potential zone of active volcanic eruption is associated with eye irritation. Indoor pollution, "sick" building or house can also be associated with eye irritation. Most ocular surface conditions are multifactorial, and several environmental factors may contribute to specific diseases. A systematic review was conducted to answer the following research question: "What are the associations between outdoor environment pollution and signs or symptoms of dry eye disease in humans?" Dry eye disease is associated with air pollution (from NO2) and soil pollution (from chromium), but not from air pollution from CO or PM10. Future research should adequately account for confounders, follow up over time, and report results separately for ocular surface findings, including signs and symptoms.

Clarifying the effect of gut microbiota on allergic conjunctivitis risk is instrumental for predictive, preventive, and personalized medicine: a Mendelian randomization analysis

Background

Allergic conjunctivitis is an ocular immune disease which affects the conjunctiva, eyelids, and cornea. Growing evidence implicates the gut microbiota in balancing and modulating immunity response, and in the pathogenesis of allergic disease. As a result, gut microbial imbalance could be a useful indicator for allergic conjunctivitis. From the perspective of predictive, preventive, and personalized medicine (PPPM), clarifying the role of gut microbial imbalance in the development of allergic conjunctivitis could provide a window of opportunity for primary prediction, targeted prevention, and personalized treatment of the disease.

Working hypothesis and methodology

In our study, we hypothesized that individuals with microbial dysbiosis may be more susceptible to allergic conjunctivitis due to an increased inflammatory response. To verify the working hypothesis, our analysis selected genetic variants linked with gut microbiota features (N = 18,340) and allergic conjunctivitis (4513 cases, 649,376 controls) from genome-wide association studies. The inverse-variance weighted (IVW) estimate, Mendelian randomization (MR)-Egger, weighted median estimator, maximum likelihood estimator (MLE), and MR robust adjusted profile score (MR.RAPS) were employed to analyze the impact of gut microbiota on the risk of allergic conjunctivitis and identify allergic conjunctivitis-related gut microbes. Ultimately, these findings may enable the identification of individuals at risk of allergic conjunctivitis through screening of gut microbial imbalances, and allow for new targeted prevention and personalized treatment strategies.

Results

Genetic liability to Ruminococcaceae_UCG_002 (OR, 0.83; 95% CI, 0.70-0.99; P = 4.04×10^-2), Holdemanella (OR, 0.78; 95% CI, 0.64-0.96; P = 2.04×10^-2), Catenibacterium (OR, 0.69; 95% CI, 0.56-0.86; P = 1.09×10^-3), Senegalimassilia (OR, 0.71; 95% CI, 0.55-0.93; P = 1.23×10^-2) genus were associated with a low risk of allergic conjunctivitis with IVW. Besides, we found suggestive associations of a genetic-driven increase in the Oscillospira (OR, 1.41; 95% CI, 1.00-2.00; P = 4.63×10^-2) genus with a higher risk of allergic conjunctivitis. Moreover, MLE and MR.RAPS show consistent results with IVW after further validation and strengthened confidence in the true causal associations. No heterogeneity and pleiotropy was detected.

Conclusions

Our study suggests that gut microbiota may play a causal role in the development of allergic conjunctivitis and provides new insights into the microbiota-mediated mechanism of the disease. Gut microbiota may serve as a target for future predictive diagnostics, targeted prevention, and individualized therapy in allergic conjunctivitis, facilitating the transition from reactive medical services to PPPM in the management of the disease.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13167-023-00321-9.

Diagnostic approach and grading scheme for canine allergic conjunctivitis

BACKGROUND

In humans, allergic conjunctivitis is a well described disease. In contrast, allergic conjunctivitis has not received much attention from the veterinary community so far. Canine allergic conjunctivitis (cAC) is one of the possible manifestations associated with canine atopic dermatitis (cAD), being often underdiagnosed and undertreated. Our aim is to contribute to disease characterization and clinical stagingfor cAC severity.

RESULTS

A retrospective observational study including 122 dogs that underwent a complete ophthalmological and dermatological examinations and diagnosed with allergic conjunctivitis was conducted. A total of six ophthalmic clinical signs were considered for disease characterization and clinical staging: conjunctival hyperemia, chemosis, ocular pruritus, epiphora, seromucoid to mucopurulent discharge and keratitis, classified from 0 (absent) to 3 (severe). Scores comprised between 1-5 were considered mild, 6-10 moderate and 11-18 severe. The majority of dogs (64%) presented with moderate cAC followed by 24% of mild stages and only 12% of severe presentations. The severity of allergic conjunctivitis was not correlated to sex or age at the time of diagnosis and all presented with a bilateral form of the disease. Chemosis (84%), hyperemia (83%) and ocular pruritus (79%) was observed in 55% of the cases. Seromucoid to mucopurulent discharge (62%) and epiphora (69%) were less frequent, with keratitis being the least encountered clinical sign (15%). The degree of keratitis showed a positive correlation with both severity and chronicity of cAC (rho = 0.21-0.29, p ≤ 0.02)). Severity of cAD and cAD were not significantly correlated (p-value = 0.4).

DISCUSSION AND CONCLUSION

The triad hyperemia, chemosis and ocular pruritus, already known in human medicine to be a reliable way of diagnosing human allergic conjunctivitis, also proved to be important in cAC Mild forms of the disease may pass unnoticed, ocular pruritus being hard to assess in canine patients.The proposed standardized diagnostic approach and novel grading scheme for cAC may be of value for both veterinary ophthalmologists and dermatologists, as well as general practitioners.

Intense Pulsed Light Attenuates Oxidative Stress in Perennial Allergic Conjunctivitis

Objective: To assess the effects of intense pulsed light (IPL) on oxidative stress (OS) in perennial allergic conjunctivitis (PAC). Background: IPL treatment has been proven effective for dry eye disease (DED). However, we have observed that, after IPL treatment, some patients with DED combined with allergic conjunctivitis (AC), an immune response condition in which excessive OS causes and exacerbates inflammatory damage, not only show an improvement in eye dryness, but also their AC-related eye itching is relieved. The mechanism by which IPL inhibits allergic reactions is not clear. Methods: Five patients with moderate-to-severe PAC were given two IPL treatments on the periorbital skin with a 2-week interval. Visual analog scale (VAS) scores and signs of AC, including eye redness and conjunctival follicles, were assessed before the first treatment (day 1) and 2 weeks after the second treatment (day 30). Tears were also collected at the same time, and lipid oxidation (LPO) metabolite analysis was performed using liquid chromatography tandem mass spectrometry (LC-MS/MS) to investigate the effects of IPL on OS response. Results: The average VAS score significantly decreased with treatment (30.2 for day 1, 10.6 for day 30; p < 0.001). The general signs of PAC showed no difference (p > 0.05). LPO metabolite analysis revealed that 17,18-diHETE, which is an oxidation product of eicosapentaenoic acid, and 13-OXoODE, which is an oxidation product of linoleic acid, are significantly downregulated after IPL treatment. Conclusions: The photothermal effect of IPL attenuates OS in PAC, and this seems to be one of the mechanisms by which IPL treatment improves PAC. Clinical Trial Registration number: ChiCTR1900022202.

Therapeutic Targets in Allergic Conjunctivitis

Allergic conjunctivitis (AC) is a common condition resulting from exposure to allergens such as pollen, animal dander, or mold. It is typically mediated by allergen-induced crosslinking of immunoglobulin E attached to receptors on primed conjunctival mast cells, which results in mast cell degranulation and histamine release, as well as the release of lipid mediators, cytokines, and chemokines. The clinical result is conjunctival hyperemia, tearing, intense itching, and chemosis. Refractory and chronic cases can result in ocular surface complications that may be vision threatening. Patients who experience even mild forms of this disease report an impact on their quality of life. Current treatment options range from non-pharmacologic therapies to ocular and systemic options. However, to adequately control AC, the use of multiple agents is often required. As such, a precise understanding of the immune mechanisms responsible for this ocular surface inflammation is needed to support ongoing research for potential therapeutic targets such as chemokine receptors, cytokine receptors, non-receptor tyrosine kinases, and integrins. This review utilized several published articles regarding the current therapeutic options to treat AC, as well as the pathological and immune mechanisms relevant to AC. This review will also focus on cellular and molecular targets in AC, with particular emphasis on potential therapeutic agents that can attenuate the pathology and immune mechanisms driven by cells, receptors, and molecules that participate in the immunopathogenesis and immunopathology of AC.

Clinical implications of miR-223 in allergic conjunctivitis and related factors affecting disease recurrence

This study aims to explore the clinical implications of miR-223 in allergic conjunctivitis (AC) and the related factors affecting disease recurrence. 47 AC patients and 58 healthy controls were enrolled to measure miR-223 expression level, serum level of inflammatory mediators, and the correlation between miR-223 and inflammatory mediators. Subsequently, AC patients were followed up for six months to record disease recurrence and explore the risk factors affecting disease recurrence. Compared to the healthy controls, the miR-223 level was lower, while inflammatory cytokines and immunoglobulins levels were higher in AC patients. There was a negative correlation of miR-223 with inflammatory cytokines and immunoglobulins. Also, miR-223 was evidently lower in AC recurrence patients than those without recurrence. Moreover, family history, pet-keeping, and other allergic histories were among the risk factors contributing to AC recurrence. These results indicate that miR-223 plays an important role in the pathology of allergic conjunctivitis.

Current Knowledge in Allergic Conjunctivitis

Allergic conjunctivitis is a disease of increasing prevalence that affects both children and adults and causes significant deterioration of their quality of life and sometimes irreversible visual damage. There are various forms of the disease, some are allergen-induced such as seasonal and perennial allergic conjunctivitis, giant papillary conjunctivitis, and contact allergic blepharoconjunctivitis, whereas others are not always explained by allergen exposure, such as vernal keratoconjunctivitis and atopic keratoconjunctivitis. We review their clinical course, characteristics, and differential diagnosis, and highlight recent advances in their pathophysiology and treatment.

The safety of orthokeratology in myopic children and analysis of related factors

OBJECTIVE

To evaluate the safety of overnight orthokeratology (OK) wear and explore whether factors such as age, refraction and allergic conjunctivitis (AC) history were associated with corneal adverse events (AEs) incidence.

METHODS

Medical records of consecutive patients who started OK for myopia correction and continued for more than one year were retrospectively reviewed. Clinical data including sex, baseline age, spherical equivalent refraction (SER), and related medical histories were retrieved. A total of 489 eyes from 260 patients (age: 8-15 years; SER: -1.00 to -6.00 D) were included. Corneal adverse events were the primary outcome. The generalized estimating equations model was used to evaluate the effects of sex, age, SER, and allergic conjunctivitis history on corneal AE incidence over the one-year period.

RESULTS

A total of 111 eyes (22.7%) had corneal AE during the one-year follow-up (corneal staining [n = 106], corneal infiltration [n = 5]) and the incidence of significant AE was 6.9%. The corneal AE incidence was associated with age (OR = 0.874, 95%CI = 0.781-0.978, p = 0.019); SER (OR=0.632, 95%CI=0.531-0.754, p < 0.001); and AC (OR=1.706, 95%CI=1.017-2.860, p = 0.043). High refraction was the key risk factor for significant AE (OR=0.542, 95%CI=0.401-0.732, p < 0.001).

CONCLUSIONS

Orthokeratology is a safe option for children with myopia. Younger age, higher myopia, and AC were risk factors for corneal AE in OK wearers. Whereas, only higher myopia was a risk factor for significant AE.

Management of vernal keratoconjunctivitis in children in Saudi Arabia

Vernal keratoconjunctivitis is a chronic inflammatory disease of the ocular surface and one of the worst types of allergic conjunctival diseases. Because of its chronic nature, it can damage the cornea, resulting in sight-threatening complications if left untreated. The disease affects mainly young children starting around the age of 7 years. We used keywords to search for published English articles in PUBMED, Google Scholar, EMBASE, and Cochrane Database of Systematic Reviews. Most of the published literature is focusing on general management of the disease and few publications focusing on treatment in the pediatric age group. We highlight the importance of how is the topical management differs between age groups. We focused on the importance of doing cycloplegic refraction for each child as the risk of keratoconus and oblique astigmatism is high in these cases. Furthermore, we highlight the importance of using eye lubricants as a therapeutic and preventive tool for the attacks of the disease. We highlight that most of the recent effective medications (especially the off-label ones) are not available in Saudi Arabia, such as tacrolimus, and some are only available to be prepared in tertiary center pharmacies as Cyclosporine A with higher concentrations.

A Review of the Differential Diagnosis of Acute Infectious Conjunctivitis: Implications for Treatment and Management

The diagnosis of acute infectious conjunctivitis can be difficult. Clinical ambiguity exists between the acute viral and bacterial as well as the allergic forms, which can confound diagnosis. Also, discrimination between viral or bacterial origins of infectious conjunctivitis based on historical, nonspecific, clinical signs and symptoms contributes to a high rate of misdiagnosis and overuse of antibiotic treatment. Therefore, in order to effectively treat acute infectious conjunctivitis, physicians must be aware of the clinical signs and symptoms and available diagnostic tests that can provide a more accurate differential diagnosis.

The effectiveness of olopatadine hydrochloride eye drops for allergic conjunctivitis: Protocol for a systematic review

BACKGROUND

Allergic conjunctivitis (AC) is a multifactorial and common type of ocular surface disease that affects many people. The quality of life for AC patients can be significantly decreased caused by symptoms of ocular itching, swelling, redness, and tearing. Topical antihistaminics, mast cell stabilizers, non-steroidal anti-inflammatory drugs (NSAIDs), and steroids have been widely used to treat AC. Many clinical trials have indicated that olopatadine hydrochloride eye drops can provide quick relief of symptoms and signs. The purpose of this review is to evaluate systematically the effectiveness of olopatadine hydrochloride eye drops for treating AC.

METHODS

A systematic review of all of the randomized controlled trials on the effectiveness and safety of olopatadine hydrochloride eye drops for AC will be conducted. We will search PubMed, Web of Science (WOS), EMBASE (OVID), the Cochrane Library, Google Scholar, China National Knowledge Infrastructure (CNKI), China Science and Technology Journal database (VIP), Wanfang Database, and CBM, from the database inception date to October 31, 2019. There are no language or publication status restrictions. Registers of clinical trials, potential gray literature, reference lists of studies, and conference abstracts will also be searched. Two reviewers will independently read the articles, extract the data information, and assess the quality of the studies. Data will be synthesized by a heterogeneity test. The primary outcomes include the main symptom and sign scores before and after treatment, the eye redness index, the presence of eosinophils in the conjunctival scraping. Quality of life, the total treatment efficacy, and safety will be evaluated as the secondary outcomes. RevMan V.5.3 software will be used for the meta-analysis.

RESULTS

The study will provide an objective and normative systematic review to evaluate the effectiveness and safety of olopatadine hydrochloride eye drops for the treatment of AC.

CONCLUSION

Our review will provide useful information to judge whether olopatadine hydrochloride eye drops is an effective intervention for patients with AC.

ETHICS AND DISSEMINATION

It is not necessary to obtain ethical approval as participants are not involved patients. The protocol and results will be published in a peer-reviewed journal. The systematic review will also be disseminated electronically and in print to help guide health care practice and policy.

PROSPERO REGISTRATION NUMBER

PROSPERO CRD42019132232.

Resolvin D1 treatment on goblet cell mucin and immune responses in the chronic allergic eye disease (AED) model

Severe, chronic eye allergy is an understudied, vision-threatening condition. Treatments remain limited. We used a mouse model of severe allergic eye disease (AED) to determine whether topical application of the pro-resolution mediator Resolvin D1 (RvD1) terminates the response. AED was induced by injection of ovalbumin (OVA) followed by topical challenge of OVA daily. RvD1 was applied topically prior to OVA. Clinical symptoms were scored. Eye washes were assayed for MUC5AC. After 7 days, eyes were removed and the number of goblet cells, T helper cell responses and presence of immune cells in draining lymph nodes and conjunctiva determined. Topical RvD1 treatment significantly reduced symptoms of AED. RvD1 did not alter the systemic type 2 immune response in the lymph nodes. AED increased the total amount of goblet cell mucin secretion, but not the number of goblet cells. RvD1 prevented this increase, but did not alter goblet cell number. Absolute numbers of CD4 + T cells, total CD11b + myeloid cells, eosinophils, neutrophils, and monocytes, but not macrophages increased in AED versus RvD1-treated mice. We conclude that topical application of RvD1 reduced the ocular allergic response by local actions in conjunctival immune response and a decrease in goblet cell mucin secretion.

[Seasonal allergic conjunctivitis]

Seasonal allergic conjunctivitis (SAC) is a frequent disease, which is often associated with allergic rhinitis and subsequently manifested as allergic rhinoconjunctivitis. In contrast to other types of chronic allergic conjunctivitis, the course of SAC is not sight-threatening. Pathogenetically, the underlying cause of SAC is an immunoglobulin E (IgE) mediated, Th2-driven type 1 hypersensitivity reaction. Clinically it presents with itching, light-red conjunctival injection as well as chemosis that exceeds the extent of conjunctival injection. The goals of treatment are relief of acute signs and symptoms, control of the underlying inflammatory process and utilization of preventive options. Dually effective local therapeutics combine the advantages of rapid action with a relatively long-lasting effect by a two-fold active approach. Specific immunotherapy is useful in selected patients.

Clinical implications of mast cell involvement in allergic conjunctivitis

The conjunctiva is a common site for the allergic inflammatory response due to it being highly vascularized, having constant exposure to environmental pollutants and allergenic pollens and having a unique conjunctival associated lymphoid tissue. The primary morbidity of anterior surface conjunctival disorders that include allergic conjunctivitis and tear film disorders is associated with its high frequency of involvement rather than its severity, although the more chronic forms can involve the cornea and lead to sight-threatening conditions. Ocular allergy is associated with IgE-mediated mast cell activation in conjunctival tissue leading to the release of preformed mediators including histamine and proteases and subsequent de novo formation of lipid-derived mediators and cytokines that trigger a cascade of cellular and molecular events leading to extensive migration and infiltration of inflammatory cells to the ocular surface. The trafficking of neutrophils, eosinophils, and lymphocytes to the ocular surface is due to establishing various chemokine gradients (mainly CCL11, CCL24, CCL5, MCP-3, and MCP-4), cell surface expression of adhesion molecules (such as VCAM-1 the ligand for VLA-4), and leukocyte adhesion to vascular endothelium. The release of preformed mediators underlies the acute ocular surface response while the secondary influx of inflammatory cells leading to the recruitment and activation of eosinophils and the subsequent activation of Th2 and Th1 lymphocytes at the level of the conjunctiva reflects the late-phase reaction.

Diagnosis and Management of Conjunctivitis for the Dermatologist

Atopic dermatitis is a chronic, sometimes relapsing inflammatory skin condition that presents with pruritus and characteristic skin manifestations. Conjunctivitis is a common ocular comorbidity affecting almost half of patients with the risk increasing with atopic dermatitis severity. Recent targeted biologic therapies that successfully treat atopic skin disease, including dupilumab, which blocks interleukin (IL)-4 and IL-13, as well as agents that block IL-13 alone, have been associated with an increased rate of conjunctivitis in clinical trials. Because conjunctivitis commonly occurs in patients with atopic dermatitis and as the treatment with targeted biologic agents may increase the risk or severity of conjunctivitis, it is important that dermatologists recognize symptoms, appreciate treatment options, and know when referral to an ophthalmologist is appropriate.

Allergic diseases in the elderly: biological characteristics and main immunological and non-immunological mechanisms

Life expectancy and the number of elderly people are progressively increasing around the world. Together with other pathologies, allergic diseases also show an increasing incidence in geriatric age. This is partly due to the growing emphasis on a more accurate and careful diagnosis of the molecular mechanisms that do not allow to ignore the real pathogenesis of many symptoms until now unknown, and partly to the fact that the allergic people from 20 years ago represent the elderly population now. Moreover, environmental pollution predisposes to the onset of allergic asthma and dermatitis which are the result of internal pathologies more than the expression of allergic manifestations. At the same time the food contamination permits the onset of allergic diseases related to food allergy. In this review we provide the state of the art on the physiological changes in the elderly responsible for allergic diseases, their biological characteristics and the major immunological and extra immunological mechanisms. Much emphasis is given to the management of several diseases in the elderly, including anaphylactic reactions. Moreover, some new features are discussed, such as management of asthma with the support of physical activity and the use of the AIT as prevention of respiratory diseases and for the purpose of a real and long lasting benefit. The mechanisms of adverse reactions to drugs are also discussed, due to their frequency in this age, especially in polytherapy regimens. Study of the modifications of the immune system is also of great importance, as regards to the distribution of the lymphocytes and also the presence of a chronic inflammatory disease related to the production of cytokines, especially in prevision of all the possible therapies to be adopted to allow an active and healthy aging.

Vehicle-Controlled, Phase 2 Clinical Trial of a Sustained-Release Dexamethasone Intracanalicular Insert in a Chronic Allergen Challenge Model

PURPOSE

To evaluate the efficacy and safety of a sustained-release dexamethasone intracanalicular insert (Dextenza™) in a model of allergic conjunctivitis.

METHODS

This was a randomized, double-masked, vehicle-controlled, Phase 2 study. Subjects had to have a positive conjunctival allergen challenge (CAC) reaction to allergen (bilateral +2 itching and redness on 5-point, 0-4 scales) at Visit 1, and for 2 of 3 time points on subsequent visits. Subjects who met entry criteria were randomized to receive Dextenza or PV (vehicle insert). Challenges occurred over 42 days, with efficacy assessed at 14 (primary endpoint visit), 28, and 40 days postinsertion. Outcome measures included the evaluation of ocular itching, redness, tearing, chemosis, eyelid swelling, rhinorrhea, and congestion.

RESULTS

Twenty-eight subjects completed the study in the Dextenza group and 31 in the vehicle group. At 14 days postinsertion, Dextenza was statistically superior to PV, with least square mean differences for ocular itching of -0.76, -0.97, and -0.87 at 3, 5, and 7 min post-CAC, and for conjunctival redness of -0.46, -0.66, and -0.68 at 7, 15, and 20 min post-CAC. Clinical significance, defined as a 1-U decrease from PV, was not met for primary efficacy. Secondary endpoints, including number of subjects reporting itching and conjunctival redness, indicated superior performance of Dextenza compared with vehicle. Eleven Dextenza-treated (35.5%) and 10 vehicle-treated (30.3%) subjects each experienced a single adverse event.

CONCLUSION

This Phase 2 study demonstrated preliminary efficacy and safety data of Dextenza for treatment of allergic conjunctivitis.

Role of CCL7 in Type I Hypersensitivity Reactions in Murine Experimental Allergic Conjunctivitis

Molecules that are necessary for ocular hypersensitivity reactions include the receptors CCR1 and CCR3; CCL7 is a ligand for these receptors. Therefore, we explored the role of CCL7 in mast cell activity and motility in vitro and investigated the requirement for CCL7 in a murine model of IgE-mediated allergic conjunctivitis. For mast cells treated with IgE and Ag, the presence of CCL7 synergistically enhanced degranulation and calcium influx. CCL7 also induced chemotaxis in mast cells. CCL7-deficient bone marrow-derived mast cells showed decreased degranulation following IgE and Ag treatment compared with wild-type bone marrow-derived mast cells, but there was no difference in degranulation when cells were activated via an IgE-independent pathway. In vivo, CCL7 was upregulated in conjunctival tissue during an OVA-induced allergic response. Notably, the early-phase clinical symptoms in the conjunctiva after OVA challenge were significantly higher in OVA-sensitized wild-type mice than in control challenged wild-type mice; the increase was suppressed in CCL7-deficient mice. In the OVA-induced allergic response, the numbers of conjunctival mast cells were lower in CCL7-deficient mice than in wild-type mice. Our results demonstrate that CCL7 is required for maximal OVA-induced ocular anaphylaxis, mast cell recruitment in vivo, and maximal FcεRI-mediated mast cell activation in vitro. A better understanding of the role of CCL7 in mediating ocular hypersensitivity reactions will provide insights into mast cell function and novel treatments for allergic ocular diseases.

Ocular itch associated with allergic conjunctivitis: latest evidence and clinical management

Allergic conjunctivitis is one of the most common allergic conditions worldwide. Its incidence is increasing due to changing climate, pollution, increased pollen loads, and the subject's heightened immunological sensitivity in response to these environmental changes. The pathophysiology predominantly involves immunoglobulin E-related mast-cell activation, with release of histamine and other mediators contributing to the propagation of the response by calling in other immune cells and further inflammation. This article presents the evolution of ocular allergy treatments, from vasoconstrictors, to antihistamines and mast-cell stabilizers, to the dual-acting agents, as well as corticosteroid and immunomodulatory options. Future targets for allergy treatment are also discussed.

Treating allergic conjunctivitis: A once-daily medication that provides 24-hour symptom relief

BACKGROUND

Allergic conjunctivitis (AC) is a common ocular inflammatory manifestation of allergen exposure in sensitized individuals. Signs and symptoms of AC can decrease quality of life, interfere with productivity, and lead to considerable economic burden. Consistent suppression of conjunctival inflammation is necessary for managing AC, but currently available medications require frequent administration and exhibit limited duration of action.

METHODS

In this review, we summarized AC pathogenesis, diagnosis, and current treatment options as well as their limitations. Findings from the literature were discussed in the context of the unmet need for a once-daily medication with sustained 24-hour effectiveness.

RESULTS

Topical pharmacologic treatments are the most common approach for managing extant AC; however, most available medications require multiple daily instillations. Dual-acting antihistamine-mast cell stabilizing agents are currently considered first-line therapeutics for AC because they provide acute relief of signs and symptoms and block persistent inflammation to promote regression of AC. Recent studies of a newly-developed, higher-concentration formulation of a dual-acting antihistamine-mast cell stabilizer have demonstrated that this formulation provides a 24-hour duration of action with once-daily dosing.

CONCLUSIONS

Dual-acting AC medications exhibit a high degree of overall effectiveness and are well tolerated for chronic use. A newly available once-daily medication that manages signs and symptoms of AC for a full 24 hours may be considered a treatment of choice for patients experiencing seasonal or perennial AC. ClinicalTrials.gov NCT01743027 and NCT01479374.

Loteprednol etabonate in the treatment of allergic conjunctivitis: a meta-analysis

OBJECTIVE

This meta-analysis was designed to assess the efficacy, as well as the safety of loteprednol etabonate (LE) ophthalmic suspension compared with placebo and other commonly used eye drops for treatment of allergic conjunctivitis.

METHODS

Comprehensive searches of randomized controlled trials were carried out in a database of Medline, Embase, and the Cochrane Library. Eight qualified studies were included. This study assessed the reduction from baseline in scores of cardinal signs and symptoms, proportion of patients with improvement of allergic signs and symptoms, and incidence of clinically significant intraocular pressure (IOP) elevation (IOP elevation ≥10 mmHg).

RESULTS

The results showed that topical LE was significantly superior to placebo in reduction from baseline in signs scores (standardized mean difference [SMD] = -0.48; 95% confidence interval [CI] = -0.65 to -0.32) and symptoms scores (weighted mean difference [WMD] = -0.51; 95% CI = -0.64 to -0.38) of allergic conjunctivitis, and as effective as olopatadine and fluorometholone acetate. Topical LE was associated with a higher improvement rate of signs (risk ratio [RR] = 1.53; 95% CI = 1.26-1.86; I (2 )= 57%) and symptoms (RR = 1.29; 95% CI = 1.15-1.46; I (2 )= 54%) than placebo and the positive control treatment. Clinically significant IOP elevation was more frequent in the group of LE than the group of control treatment (pooled odds ratio = 3.03; 95% CI = 1.04-8.80), which was affected by the response to corticosteroid of the individual patient and the wearing of contact lenses.

CONCLUSIONS

Topical LE is effective in treating allergic conjunctivitis. However, it should be used with caution due to the higher incidence of IOP elevation compared with placebo and olopatadine. A large-scale trial would be required to confirm the effect of different concentrations of LE on IOP.

Prevalence of allergic conjunctivitis among basic school children in the Kumasi Metropolis (Ghana): a community-based cross-sectional study

BACKGROUND

There seems a preponderance of hospital-based studies on the prevalence of Allergic Conjunctivitis (AC) compared to community-based ones, particularly among children in Ghana and Africa as a whole. Meanwhile, literature supports the possibility of underdiagnosing AC in the hospital setting; exponentially so when males generally have poor hospital-attending behavior. This may lead to underestimation of the true burden of AC. Consequently, the purpose of the current community-based study was to determine the prevalence of AC among basic school children in the Kumasi Metropolis, while identifying its associated symptoms.

METHODS

A cross-sectional community-based study involving 1571 students from 11 basic schools (Primary and JHS) participated in the study. Data collection started in November 2011 and was completed in March 2014. After history taking, subjects underwent a battery of tests; visual acuity, objective refraction, anterior and posterior segments examination with a slit-lamp and a direct ophthalmoscope respectively.

RESULTS

The prevalence of AC was 39.9 %. The mean (± SD) age of participants was 8 ± 0.65 years. AC was significantly associated with gender (p < 0.05), but not with age (p > 0.05). A total of 70 % of the students with AC never had any form of treatment.

CONCLUSIONS

AC is an endemic ocular disease among basic schools in the Kumasi metropolis and therefore calls for pragmatic and proactive measures to reduce its burden and effects on its victims. Public health measures may be required to help reduce the burden associated with this condition.

Advances in pharmacotherapy for allergic conjunctivitis

INTRODUCTION

Allergy is the fifth leading group of chronic diseases, affecting as much as 40% of the first-world population. Its pathophysiology has a genetic component, and is driven by the immune system's sensitized response to antigens and environmental factors. As research continues to uncover the mediators responsible for ocular allergy, the development of novel drugs should progress.

AREAS COVERED

A literature review of allergic conjunctivitis, ocular allergy and their treatment was performed using PubMed and Medline. Additional information is also included from clinicaltrials.gov and associated web sites for drugs currently in clinical trials.

EXPERT OPINION

The initial step of therapy remains identification and avoidance of allergic triggers. The mainstay of treatment is the new generation of dual-acting antihistamines. Drugs that improve the magnitude and duration of relief, with greater subject responder rates, are gradually making their way into the clinic. Allergic conjunctivitis is a relatively easy disease to study because of the availability of models such as the conjunctival allergen challenge. New classes of drugs that target inflammatory pathways or mediators involved in the early and late-phase allergic response are being screened in these models and we are making progress in identifying the next generation of anti-allergic therapy.

Clinical characteristics associated with conjunctival inflammation in allergic rhinoconjunctivitis

BACKGROUND

Allergic rhinitis affects up to 30% of the general population worldwide and is increasing in prevalence. Among several comorbidities, conjunctivitis is probably the most common and occurs so frequently with allergic rhinitis that the term allergic rhinoconjunctivitis (ARC) has been coined.

OBJECTIVES

The cytological characteristics of conjunctival inflammation in patients with ARC were assessed and then correlated to clinical characteristics.

METHODS

Fifty-one patients with clinically diagnosed ARC (23 men; 32.4 ± 13.5 years old) underwent a detailed clinical history and standard diagnostic allergy workup as well as nasal and conjunctival scraping for cytological analysis. Patients were subdivided into 3 groups on the basis of cytological phenotype: (1) nasal and conjunctival inflammation, (2) nasal inflammation only, and (3) no mucosal inflammation.

RESULTS

Group 1 patients reported significantly higher eye itching scores (5.8 ± 2.9 on a 0-10 scale) than did patients in group 2 (3.8 ± 2.8; P = .06) or 3 (2.6 ± 2.9; P = .018) and were mostly men (81.8%). Male sex (odds ratio, 8.4; P = .005) and eye itching (odds ratio, 1.3; P = .019) significantly correlated with conjunctival inflammation. The odds of exhibiting conjunctival inflammation, at multivariate analysis, increased 13-fold for men and 1.5-fold for each point on the eye itching scale. A cutoff value of 3 or more for eye itching effectively identified patients with conjunctival inflammation.

CONCLUSIONS

Our study demonstrates that some clinical manifestations of ARC correlate well with conjunctival inflammation.

Efficacy of olopatadine versus epinastine for treating allergic conjunctivitis caused by Japanese cedar pollen: a double-blind randomized controlled trial

Introduction

The objective of this study was to compare the efficacy and safety of olopatadine versus epinastine in healthy Japanese adults with a history of allergic conjunctivitis to Japanese cedar pollen.

Methods

This Phase IV double-blind randomized controlled clinical trial comprised three clinical visits over 30 days. Screening tests were performed to identify subjects with a history of allergic conjunctivitis to Japanese cedar pollen in terms of skin sensitivity and positive bilateral reactions to a conjunctival allergen challenge (CAC) with Japanese cedar pollen at Visit 1, and confirmation by a positive bilateral CAC reaction at Visit 2. At Visit 3, the subjects were randomized to receive one drop of olopatadine HCl ophthalmic solution 0.1% (olopatadine) in the left or right eye (1:1 ratio). All subjects received one drop of epinastine HCl ophthalmic solution 0.05% (epinastine) in the contralateral eye as an active control. Five min later, the subjects underwent bilateral CAC tests with one drop of the allergen solution at the concentration that elicited positive reactions at Visits 1 and 2. Efficacy outcomes included the severity of ocular itching at 5, 7, and 15 min and the severity of conjunctival hyperemia at 7, 15, and 20 min after the CAC test, as graded by the investigator by biomicroscopy.

Results

Fifty people participated in this study (25 per group). Olopatadine significantly reduced ocular itching at 7 and 15 min (both p < 0.05) and conjunctival hyperemia at 7 and 20 min (p = 0.0010 and p < 0.05, respectively) after allergen exposure compared with epinastine. There were no adverse events for either treatment.

Conclusion

The results of this single-dose study suggest that olopatadine is superior to epinastine in terms of suppressing ocular itching and hyperemia induced by Japanese cedar pollen during CAC tests. Further studies are needed to confirm these findings in real-life settings.

Electronic supplementary material

The online version of this article (doi:10.1007/s12325-014-0156-2) contains supplementary material, which is available to authorized users.

Emerging drugs for allergic conjunctivitis

INTRODUCTION

Allergic conjunctivitis (AC) is a very common disease, especially in association with allergic rhinitis but may also occur in isolated presentation. The treatment of AC has long been based on antihistamines, cromones and topical corticosteroids, but none of these drugs completely abolishes the clinical expression of AC.

AREAS COVERED

The development of new drugs for AC is analyzed highlighting the recent insights into the pathophysiological mechanisms of the disease. The major aim of development of drugs for AC is to have agents able to prevent the inflammatory effects of the interaction between the allergen and the specific IgE antibodies on mast cell surface. This may be obtained by blocking the effects of histamine (the main mediator of early allergic response) by H1-receptor antagonists, inhibiting the release of soluble factors able to recruit inflammatory cells (that sustain prolonged inflammation) by mast-cell stabilizers, inhibiting the effects of single mediators, inducing tolerance to the allergen by specific immunotherapy or even acting on factors related to activation and differentiation of T lymphocytes such as the toll-like receptors.

EXPERT OPINION

AC is an underestimated disease for which there is a search of more effective treatments. The availability of the drugs under current evaluation will allow more refined therapeutic strategies to apply according to the characteristics and the clinical severity of AC.