Allergic conjunctivitis



The conjunctiva lines the back of the lid, extends into the space between the lid and the globe, and spreads up over the sclera to the cornea. The appearance of the conjunctiva changes in response to various stimuli. Conjunctival blood vessels can dilate or can bleed (extravasations blood beneath the conjunctiva, called a sub conjunctival haemorrhage), there can also be inflammation of the conjunctiva, this may be caused by any one of three reasons, and this is what is commonly known as conjunctivitis or eye flu. These three types of conjunctivitis are; irritant, infective and allergic.
Allergic conjunctivitis or hay fever conjunctivitis as it is also known is an acute seasonal conjunctival inflammation caused by an allergy, generally to airborne pollens. This conjunctivitis is due to a type I anaphylactic hypersensitivity reaction to a specific antigen, usually airborne pollens.
Symptoms signs and diagnosis patients complain of bilateral conjunctival hyperemia, watery discharge and ocular itching. Most patients also complain of a simultaneous bout of rhinitis. Many patients have other atopic diseases as eczema and asthma. Ocular itching often leads to eye lid rubbing and edema. The conjunctivitis is recurrent and seasonal with symptoms peaking during spring, late summer, and early fall. The bulbar and tarsal conjunctivae are hyperemic, but the predominant feature is edema. The bulbar conjunctiva appears translucent, bluish and thickened. The papillae on the tarsal conjunctivae give it a velvety appearance, and chemosis not an uncommon site. The diagnosis is usually made on the basis of clinical grounds. Eosinophills are generally present in conjunctival scrapings, which may be taken from the lower or upper tarsal conjunctiva.
Treatment avoidance a reduce symptoms and occasionally antigen desensitization is found to be very useful. Topical OTC antihistamines and vasoconstrictors (ex: naphazoline HCL/ pheniramine maleate) are useful in mild cases of allergic conjunctivitis. Topical prescription antihistamines such as levocabastine, non steroidal anti-inflammatory drugs such as ketorolac, or topical mast cell inhibitors such as lodoxamide can be used separately or in combination if OTC preparations do not provide sufficient respite. Topical corticosteroids like flurometholone0.1% or prednisolone acetate 0.12 to 1.0% drops three times a day can be very useful in recalcitrant cases. Because corticosteroid treatments can exacerbate ocular herpes simplex virus infections, leading to a possible complication of corneal ulceration and perforation, or with long term use lead to glaucoma and possibly cataracts, hence the use of corticosteroids should only be initiated and monitored under the supervision of an ophthalmologist.
Complications and prevention; complications are rare but recurring symptoms are a source of irritation, it also affects daily life specially being a hindrance at work, but do not pose any long term health issues. Whereas dermatoconjunctivits and giant papillary conjunctivitis may cause severe complications such as keratitis; which causes severe pain, photophobia, blurred vision and constant irritation this may lead to an eventual ulceration of the cornea and if left untreated may eve impair your vision permanently. Prevention entails avoidance and understanding your condition. Use of glasses and goggles is highly effective as is the prophylactic use of topical antihistamines during spring.

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