Ocular allergy: recognizing and diagnosing hypersensitivity disorders of the ocular surface

Abstract

Ocular allergy includes several clinically different conditions that can be considered as hypersensitivity disorders of the ocular surface. The classification of these conditions is complex, and their epidemiology has not been adequately studied because of the lack of unequivocal nomenclature. Ocular allergy symptoms are often, but not always, associated with other allergic manifestations, mostly rhinitis. However, specific ocular allergic diseases need to be recognized and managed by a team that includes both an ophthalmologist and an allergist. The diagnosis of ocular allergy is usually based on clinical history and signs and symptoms, with the support of in vivo and in vitro tests when the identification of the specific allergic sensitization is required for patient management. The aims of this Task Force Report are (i) to unify the nomenclature and classification of ocular allergy, by combining the ophthalmology and allergy Allergic Rhinitis and its Impact on Asthma criteria; (ii) to describe current methods of diagnosis; (iii) to summarize the therapeutic options for the management of ocular allergic inflammation. Ocular allergy is a localized allergic condition that is observed as the only or dominant presentation of an allergic sensitiza-tion, or is associated with rhinitis. It is not a single clinical entity, but includes several conditions with different pathogen-esis, hypersensitivity mechanisms, diagnostic criteria, and management. Ocular allergies are encountered daily in the phy-sician's office. Approximately 15-20% of the world population is affected by some form of allergic disease; ocular symptoms are estimated to be present in 40-60% of allergic patients (1) and contribute significantly to poor quality of life (2-4). Most of the available prevalence data encompass both ocular and nasal symptoms, making it impossible to separate ocular allergy from allergic rhinitis. Moreover, the frequently confusing nomenclature makes estimations of prevalence difficult. The purpose of this position paper is to unify the nomenclature and classification of ocular allergies, in order to facilitate the exchange of information and knowledge on diagnosis and management between allergists and ophthalmologists. The existing evidence for treatment options was evaluated using the SIGN criteria (5). Classification and nomenclature The ocular allergy nomenclature is based either on clinical signs and symptoms (Table 1) or on pathophysiology, according to the different hypersensitivity mechanisms introduced by Gell and Coombs. In 2001, the European Academy of Allergy and Clinical Immunology (EAACI)

Antihistamines and allergy

“…It can be seasonal due to pollens or perennial due to allergens present all year. 13 Seasonal allergic conjunctivitis is typically associated with some degree of allergic rhinitis so allergen avoidance is the first step in management.…”

Ocular allergy

“…Its pathological process involves chronic degranulation of the mast cells mediated by IgE, and immune mechanisms mediated by Th1 and Th2-lymphocytes derived cytokines, eosinophils and other inflammatory cells (Leonardi et al, 2007). AKC is often associated with atopic co-morbidities such as asthma and eczema, and therefore requires multi-disciplinary management (Leonardi et al, 2007).…”

“…The most common clinical presentations of ocular allergy are conjunctival hyperaemia (redness) and chemosis (swelling), itching and tearing, and vision loss in severe cases (Chowdhury, 2013;Leonardi, De Dominicis, & Motterle, 2007). Management of this condition is based on minimising contact of the causal allergen with the conjunctiva using a series of protective measures, with medication assisting in controlling the symptoms produced by the allergic inflammatory process (Chowdhury, 2013;La Rosa et al, 2013).…”

“…However, a serious limitation of this classification is contact dermatoconjunctivitis (CDC), which is a 'non-IgE-mediated form of localized contact dermatitis, but immunologically different from VKC or AKC' (Leonardi et al, 2007). In addition, 'contact lens-related GPC should be considered as non-IgE mediated, mechanically related to the lens micro-trauma, which, however, shares some immunopathological aspects with VKC' (Leonardi et al, 2007), which can lead to more confusion. The above-mentioned limitations prompted the international h e a l t h s a g e s o n d h e i d 2 2 ( 2 0 1 7 ) 1 1 2 e1 2 2 Ocular Inflammation Society (IOIS) to propose a more comprehensive classification that included both the 'IgEmediated' SAC and PAC and the 'non-IgE-mediated' VKC and AKC (Table 1).…”

Alcaftadine 0.25% versus Olopatadine 0.1% in Preventing Cedar Pollen Allergic Conjunctivitis in Japan: A Randomized Study

“…2 Studies in developed countries have reported that 14-40% of the population suffer from allergic conjunctivitis. [3][4][5][6] In Japan, the estimated prevalence of allergic conjunctivitis is 15-20% and is most commonly associated with Japanese cedar pollen. 7 In susceptible individuals, ocular exposure to allergens leads to immunoglobulin E-mediated mast cell degranulation and subsequent release of histamine and other inflammatory mediators.…”