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1 Allergy Reaction of the body tissues to an allergen which leads to production of antibodies finally culminating in an antigen-antibody antibody reaction.

2 Normal Individual Entry of allergen Allergen-Antibody Antibody reaction Production of antibodies Immune system Destruction of Allergen

3 Allergic Process Antigen IgE antibody Attachment of IgE to mast cell Degranulation Chenotactic Factors Migration & Activation Histamine H1- Receptor Late Phase Histamine Release Basophils Eosinophils Chemotactic Mediators Neutrophils Irritation of Nose Eye Skin Bronchi EARLY PHASE Inflammation & Tisse Damage LATE PHASE

4 Removal of the cause Symptom control is aided by reducing exposure to the precipitating factor, which could be either Pollen House dust mite Contact lens Artificial eye

5 Secondary Allergic Reaction Inflammatory cells (eosinophils) are activated and attracted to the site of the allergic reaction Activated inflammatory cells (eosinophils) release secondary mediators Inflammation + hyperactivity + tissue damage Secondary activation of mast cells causes late histamine release Second wave of allergic symptoms (sneezing, itching, nasal congestion, watery eyes, runny nose etc.)

6 ALLERGIC CONJUNCTIVITIS : TYPES Allergic conjunctivitis may be divided into 5 major subcategories: Seasonal allergic conjunctivitis iti (SAC) perennial allergic conjunctivitis (PAC). Vernal keratoconjunctivitis (VKC), Atopic keratoconjunctivitis (AKC), and Giant papillary p conjunctivitis (GPC)

7 GIANT PAPILLARY CONJUNCTIVITIS GPC is an immune-mediated mediated inflammatory disorder of superior tarsal conjunctiva. The primary finding is the presence of "giant" papillae, which are typically greater than 0.3 mm in diameter. GPC represents an immunologic reaction to a variety of foreign bodies, which may cause prolonged mechanical irritation to the superior tarsal conjunctiva. Allergens : contact lenses (hard and soft) are the most common irritant, ocular prostheses, extruded scleral buckles, and exposed sutures following previous surgical intervention may precipitate GPC.

8 Giant Papillary Conjunctivitis Spring (1974) was the first to describe this disease. Commonly develops after lens use Also associated with ocular prostheses, exposed sutures after cataract surgery, corneal transplants and extruded scleral buckles. Estimated 1-3% of the 30 million lens wearers in USA develop the condition Soft lens wearers % 15% Hard lens wearers -1-5% Drugs, 1991; 42(4): , Acta Ophthalmalogica Scandinavica 1999; 77:

9 Symptoms Lens intolerance Excessive mucus secretion Giant Papillary Conjunctivitis i i Blurred vision due to coating on the surface of the contact lens Signs Large papillae on the upper conjunctiva Hyperaemia Mucus discharge covering areas of giant papillae (> 1 mm in diameter which has a cobble stone appearance due to its polygonal, flat topped manifestation)

10 Giant Papillary Conjunctivitis i i

11 Seasonal Allergic Conjunctivitis i i SAC is the most common form of the disease and represents about half the cases of allergic conjunctivitis. ct t Perennial allergic conjunctivitis (PAC) is a variant of SAC which is chronic with year around symptoms. The prevalence is 0.035% Most common allergen is pollen or spore

12 SAC AND PAC :PATHOPHYSIOLOGY Since conjunctiva is a mucosal surface similar to the nasal mucosa, the same allergens that trigger allergic rhinitis may be involved in the pathogenesis of allergic conjunctivitis. Common airborne antigens : pollen, grass, and weeds may provoke the symptoms of acute allergic conjunctivitis such as ocular itching, redness, burning, and tearing. SAC :symptoms during a particular season PAC : symptoms that t lasts the whole year

13 Signs and Symptoms Red, itchy eyes Seasonal Allergic Conjunctivitis i i Burning, stinging, photophobia and a watery or a ropy discharge Conjunctiva takes on a pinkish, milky appearance Contact lens intolerance

14 Seasonal Allergic Conjunctivitis i i

15 Vernal Keratoconjunctivitis Also known as spring catarrh Primarily seen in prepubertal children occurs more often in boys than in girls Prevalence : 0.5 2% of ocular allergic disease Long duration (up to 10 years) Commonly seen in hot and dry such as Middle East, Africa and the Indian subcontinent Shows seasonal variations in severity, being worst over the warm spring and summer months Ref.: Drugs of Today, 1998; 34(11):

16 Hay fever (seasonal allergic) Conjunctivitis t This is very common and innocuous condition is usually managed by a non-ophthalmologist. ophthalmologist. It is often associated with seasonal rhinitis. Clinical features The symptoms are transient attacks of itching, lacrimation, and redness during the hay fever season. The conjunctiva shows mild chemosis and a diffuse papillary reaction In severe cases, the eyelids may be slightly oedamatous but the cornea is uninvolved.

17 Vernal Keratoconjunctivitis Also known as spring catarrh Primarily seen in prepubertal children occurs more often in boys than in girls Prevalence : 0.5 2% of ocular allergic disease Long duration (up to 10 years) Commonly seen in hot and dry such as Middle East, Africa and the Indian subcontinent Shows seasonal variations in severity, being worst over the warm spring and summer months Ref.: Drugs of Today, 1998; 34(11):

18 VERNAL KERATOCONJUNCTIVITIS VKC is a chronic bilateral inflammation of the conjunctiva, commonly associated with a personal and/or family history of atopy. More than 90% of patients with VKC exhibit one or more atopic conditions such as asthma, eczema, or seasonal allergic rhinitis.

19 Vernal Keratoconjunctivitis (Contd.)

20 ATOPIC KERATOCONJUNCTIVITIS AKC is a bilateral inflammation of conjunctiva and eyelids, which has a strong association with atopic dermatitis. It is also a type I hypersensitivity disorder with many similarities to VKC, yet AKC is distinct in a number of ways. In 1953, Hogan first described the association between atopic dermatitis and conjunctival inflammation. Approximately 3% of the population is afflicted with atopic dermatitis and of these approximately 25% have ocular involvement

MAJOR DIFFERENTIATING FACTORS BETWEEN VKC AND AKC Characteristics Age at onset Sex Seasonal variation Discharge VKC Generally presents at a younger age Males are affected preferentially

of conjunctival scarring Horner-Trantas dots Corneal neovascularization Presence of eosinophils in conjunctival scraping Horner-Trantas dots and shield ulcers are commonly seen Not present

21 MAJOR DIFFERENTIATING FACTORS BETWEEN VKC AND AKC Characteristics Age at onset Sex Seasonal variation Discharge VKC Generally presents at a younger age Males are affected preferentially Typically a disorder that occurs during spring months Thick mucoid discharge AKC No sex predilection Generally perennial Watery and clear discharge Conjunctival scarring - Higher incidence of conjunctival scarring Horner-Trantas dots Corneal neovascularization Presence of eosinophils in conjunctival scraping Horner-Trantas dots and shield ulcers are commonly seen Not present Conjunctival scraping reveals eosinophils to a greater degree in VKC Presence of Horner-Trantas dots is rare Tends to develop deep corneal neovascularization Presence of eosinophils is less likely

22 Therapy Removal of the cause Artificial tears Vasoconstrictors Antihistamines t i Cyclo-oxygenase oxygenase inhibitors (NSAIDS) Mast cell inhibitors Steroids

23 ARTIFICIAL TEARS Artificial tear substitutes provide a barrier function and help to improve the first-line defense at the level of conjunctival mucosa. Artificial tear substitutes help to dilute various allergens and inflammatory mediators Artificial tear substitutes they help flush the ocular surface of these agents

24 VASOCONSTRICTORS Vasoconstrictors are available either alone or in conjunction with antihistamines to provide short- term relief of vascular injection and redness. Common vasoconstrictors include naphazoline, phenylephrine, oxymetazoline, and tetrahydrozoline.. These pharmacologic agents are ineffective against severe ocular allergies and against other more severe forms of allergic conjunctivitis, such as atopic and vernal disease.

25 ANTIHISTAMINES Systemic and/or topical antihistamines may be given to relieve acute symptoms due to interaction i of histamine i at ocular H1 and H2 receptors. systemic side affects such as drowsiness and dry mouth. Topical antihistamines competitively and reversibly block histamine receptors and relieve itching and redness but only for a short time.. e.g: epinastine and azelastine. potent antihistamines have a rapid onset and are effective in relieving i the signs and symptoms of allergic conjunctivitis.

26 NSAIDS Nonsteroidal anti-inflammatory inflammatory drugs (NSAIDs) act on the cyclooxygenase metabolic pathway and inhibit production of prostaglandins and thromboxanes. They have no role in blocking mediators formed by the lipoxygenase pathway such as leukotrienes. Common NSAIDs that are approved for allergic indications include ketorolac tromethamine.

27 MAST CELL STABILISERS Mechanism of action: : Decrease in degranulation of mast cells, which prevents release of histamine and other chemotactic factors. Note that mast cell stabilizers do not relieve existing symptoms and are to be used on a prophylactic basis to prevent mast cell degranulation with subsequent exposure to the allergen. Therefore, they need to be used long term in conjunction with various other classes of medications. Common mast cell stabilizers include cromolyn sodium and lodoxamide,olopatadine, nedocromil,and ketotifen

28 CORTICOSTEROIDS Corticosteroids exist in various forms and potencies. Relatively weak steroids such as rimexolone, medrysone, and fluorometholone tend to have less potency with fewer ocular side effects. In contrast, t agents such as prednisolone acetate t are more potent t and have a higher incidence of side effects. A relatively new steroid, loteprednol etabonate, is rapidly metabolized once it enters the anterior chamber of the eye. Therefore, it is extremely useful in treating ocular surface and superficial corneal inflammations. loteprednol has a specific indication for ocular allergy and has been shown in clinical studies to have fewer ocular side effects. topical steroids should be prescribed only for a short period of time and for severe ere cases that do not respond to conventional therapy

29 ALLERGIC CONJUNCTIVITIS : CIPLA S RANGE Artificial ca tears : Add tears, Flow gel : to wash away inflammatory mediators Mast cell stabilisers: Cromal/Cromal forte: prophylactic hl agent for allergic conjunctivitis iii NSAIDS: Ketodrops :USFDA approval for SAC STEROIDS: Flomex : recommended for paediatric allergic conjunctivitis. Loteflam :the only steroid approved by USFDA for all types of allergic conjunctivitis

Ocular Allergies: Scratching the Surface. -20%-50% of the population has allergies -83% of allergy sufferers experience ocular symptoms

How Many People Are Affected? Ocular Allergies: Scratching the Surface Mile Brujic, OD -20%-50% of the population has allergies -83% of allergy sufferers experience ocular symptoms Disclosure: I have no