Ocular Allergy - Katelaris C, Smith P (Updated 2020)
Ocular Allergy
Updated: September 2020
Updated: June 2015
Originally Posted: July 2004
Updated by:
Professor Connie Katelaris, MD, PhD
Clinical Associate Professor, Dept. of Clinical Immunology and Allergy
Westmead Medical Centre
Westmead, Australia
Professor Pete Smith, MBBS, BMedSci, PhD, FRA
Professor in Clinical Medicine
Griffith University and Bond University
Queensland, Australia
Original Author:
Professor Connie Katelaris, MD, PhD
Clinical Associate Professor, Dept. of Clinical Immunology and Allergy
Westmead Medical Centre
Westmead, Australia
Definition
Allergic conjunctivitis is a broad group of allergic conditions involving inflammation of the conjunctiva. The commoner conditions are mild and do not affect the cornea. The rarer diseases involve the cornea and can be sight-threatening. Allergic conjunctivitis is a very common condition that occurs with allergic rhinitis and contributes to burden of disease and QOL. Allergic conjunctivitis is often under-recognized both by patients and doctors.
Classification
Seasonal, IgE-mediated allergic conjunctivitis (SAC)
Perennial, IgE-mediated allergic conjunctivitis (PAC)
These common IgE-mediated diseases are related to seasonal or perennial allergens. They are characterized by symptoms of ocular itching, watering and redness, and signs of hyperaemia and oedema of the tarsal conjunctival surfaces. There is frequently an association with allergic rhinitis. SAC is intermittent in nature, and, in temperate regions, follows exposure to pollen allergens in sensitized individuals. PAC is a mild, persistent form of allergic conjunctivitis resulting from continuing exposure to persistent allergens such as house dust mites.
Vernal keratoconjunctivitis (VKC)
This is a severe inflammatory disease that may be intermittent or, less frequently, persistent. VKC is, in about 60% of cases, associated with IgE-dependent hypersensitivity. The symptoms are ocular watering, stickiness from mucus discharge, itching, and difficulty with opening the eyes on awaking. If the cornea is involved, pain, blurred vision and photophobia are experienced. The signs are giant papillary hyperplasia of the upper tarsal conjunctival surfaces, erosion of the corneal epithelium and inflammation at the limbus.
Atopic keratoconjunctivitis (AKC)
This is a severe disease which is associated with atopic eczema. The condition is lifelong, starting in the third of fourth decade. IgE-mediated mechanisms may be implicated. The symptoms are perpetual ocular itching, soreness, impaired vision and a sensation of dryness. Signs include chronic lid margin infection, chronic cicatrising conjunctivitis, eczema of the eyelids, tear abnormality, and progressive scarring and vascularization of the cornea.
Giant papillary conjunctivitis (GPC)
This disease, also known as foreign body associated papillary conjunctivitis, results from trauma caused by contact lens edges, ocular protheses or post-operative sutures. It may also evolve from spontaneous lid eversion resulting in conjunctival rubbing against the pillow, the so-called floppy eyelid syndrome. Upper subtarsal papillae, not always giant in size (> 1mm), are the hallmark sign of the disease. There is no evidence that generally IgE-sensitized individuals are at greater risk of developing the disease. The cornea is rarely involved.
Causes
Seasonal (intermittent) IgE-mediated allergic conjunctivitis
Seasonal (intermittent) allergic conjunctivitis is triggered by the same allergens responsible for intermittent allergic rhinitis. In the Northern Hemisphere these are tree pollen in April/May, grass pollen in June/July, and mold spores and weed pollen in July/August.
Perennial (persistent) IgE-mediated allergic conjunctivitis
Perennial (persistent) allergic conjunctivitis is triggered by house dust mites, molds and animal allergens, which may be present year round, although the symptoms do show some seasonal variation. In the Southern Hemisphere the pollen season can be all year round, depending on the region.
Vernal keratoconjunctivitis
The majority of cases of VKC are intermittent and can occur during the high pollen season, although persistent cases do occur in warm subtropical or desert climates. Published reports of the association with IgE-mediated atopic disease vary between 15% to 60%. While there is a relationship between the condition and positive skin tests, the relationship is not necessarily causal.
Atopic keratoconjunctivitis
AKC is a perennial disease which, when associated with the IgE-mediated subgroup of atopic eczema, may be exacerbated by contact with specific allergens such as house dust mites, mold spores and animal danders.
Giant papillary conjunctivitis
Giant Papillary Conjunctivitis occurs in the presence of foreign bodies in the eye, such as contact lenses or ocular prostheses. Papillae develop on the upper tarsal conjunctiva along the line of contact with the source of mechanical trauma, e.g., the lens edge. The upper eyelid may be traumatized with each blink of the eye, which occurs between 10,000 and 12,000 times daily, and the area of trauma may serve as an entrance for antigen possibly derived from altered proteins or chemicals in contact lens solutions, although no single causative allergen has been identified in this condition to date.
Diagnosis of Allergic Conjunctivitis
Clinical history
- Typical symptoms
- 80% of patients are under 30 years of age
- Strong personal or family history of IgE-mediated diseases
- Recurrent intermittent or persistent symptoms
Clinical examination and investigations
- Appearance of the everted (flipped) eyelid. This may be performed by using a long thin object, such as a cotton bud, as a fulcrum at the top of the tarsal plate, while the eyelashes are pulled forward and up.
- Conjunctival scrapings for eosinophils may be helpful, but rarely performed
- Skin prick tests or in-vitro specific IgE tests to identify causative allergens
Mediators of IgE-related reactions in allergic conjunctivitis
- Histamine: Itching, redness, oedema
- Prostaglandins: Sensitized nerves, enhanced pain, oedema and redness
- Leukotrienes: Chemotaxis, oedema and vascular permeability
- Chemotactic factors: Recruitment of eosinophils and neutrophils leading to tissue destruction
Differential diagnoses of allergic conjunctivitis include
- Atopic blepharitis
- Bacterial conjunctivitis
- Chlamydial conjunctivitis
- Corneal abrasion or ulceration
- Dry eye
- Episcleritis
- Epithelial microcysts and vacuoles
- Staphylococcal marginal keratitis
- Superficial punctate keratitis
- Tight lens syndrome
- Viral conjunctivitis or keratitis
Ocular itching is a cardinal symptom of allergic eye disease and in the absence of itching an alternative diagnosis should be suspected.
Epidemiology
SAC
SAC may occur alone or as a component of seasonal/intermittent allergic rhinitis (hay fever). Both SAC and PAC are primarily diseases of young adults, and there is a slightly higher prevalence in males.
VKC
VKC is a disease of childhood and early adolescence. Genetic factors and atopic status may be involved in the development of the disease, although many patients have no familial or personal history of atopy, and may have negative allergy diagnostic tests. Thus, like atopic eczema it might represent a syndrome with allergic and non-allergic subgroups. Males are more frequently affected than females, with a ratio of 3:1. The disease usually begins before the age of 10 years and remits at the time of puberty, although the age of affected individuals ranges from 3 to 25 years of age. VKC may progress to atopic keratoconjunctivitis.
VKC occurs more frequently in warm climates and subtropical areas, in particular the Mediterranean area, central Africa, India and South America. It is also reported in Australia, China, Japan and North America. The incidence of the disease in cooler climates in Northern Europe is thought to reflect migration of susceptible individuals, and it is thought that both genetic and environmental factors contribute to the development of the disease.
AKC
AKC first occurs in the late teens or early twenties with a peak incidence between the ages of 30 – 50 years. It is more frequent in men and occurs in up to 25% of patients with atopic eczema. There is usually a personal or family history of atopic disease.
GPC
GPC associated with contact lens use reflects the age of contact lens wearers and thus rarely occurs in children or the elderly. However when associated with post-surgical mechanical trauma, such as exposed sutures, it is more prevalent in older age groups. There is no gender predominance.
Prevention
Allergen avoidance can lead to significant improvement in symptoms of SAC and PAC. In GPC, the use of disposable contact lenses may be helpful if lens deposits are causing symptoms, and changing to daily use of disposable lenses can eliminate the condition entirely.
Treatment
Recommendations for the treatment of seasonal, intermittent, and perennial, persistent allergic conjunctivitis are available on the GLORIA area of this website. Treatment of the rarer, more severe forms of allergic conjunctivitis requires the use of topical corticosteroids and should be managed by an ophthalmologist. Prolonged use of topical steroids in the eye can lead to secondary bacterial infection, intra-ocular hypertension, glaucoma and cataract, and thus regular monitoring is essential.
Topical cyclosporine eye drops are approved for use in the US for chronic dry eye syndrome, and is often used in patients with severe VKC and AKC as a steroid-sparing agent. The following algorithm offers a suggested approach for the treatment of allergic rhinitis and allergic conjunctivitis:
Additional references for the treatment of allergic conjunctivitis:
VKC
Cromones and other mast cell stabilisers may be prescribed alone, or in addition to topical steroid therapy. Mucolytic drops (acetylcisteine 5% or 10%) may be used to control the symptoms caused by abnormal mucus.
AKC
In addition to topical corticosteroid therapy, treatment of the infected lid margins with topical or systemic antibiotic may help to reduce symptoms. Cromones and other mast cell stabilizers may be of value. Treatment of eye lid eczema with steroid ointments may be of value. For ocular involvement, controlled trials of topical 0.05% cyclosporin A have shown safety as well as improvement in signs and symptoms in AKC in mild and refractory cases
-Akpek EK, Dart JK, Watson S, et al. A randomized trial of topical cyclosporin 0.05% in topical steroid-resistant atopic keratoconjunctivitis. Ophthalmology.2004; 111:476 – 482.
-Daniell M, Constantinou M, Vu HT, Taylor HR. Randomised controlled trial of topical ciclosporin A in steroid dependent allergic conjunctivitis. Br J Ophthal- mol 2006; 90:461 – 464.
GPC
The condition, fit and cleaning schedule of contact lenses or prosthesis should be reviewed. Opticrom or similar drugs may be used if required. Topical steroids should not be used for contact lens wearers, but may be given for prosthesis wearers, where no risk to damage of the eye can occur.