الفهرس 
ANATOMY OF THE CONJUNCTIVAOnly 14 pages are availabe for public view
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Abstract
Allergic conjunctivitis is a common condition affecting
approximately 17 to 20% of the children, and its incidence is
increasing especially in rural communities.
Allergic conjunctivitis is an acute, intermittent, or chronic
conjunctival inflammation usually caused by airborne allergens.
The clinical presentation of the various forms of allergic
conjunctivitis can vary greatly, from mild symptoms
unaccompanied by ocular signs, to severe disease with visionthreatening
complications.
Although an IgE-mediated immediate hypersensitivity
reaction has been demonstrated or postulated in many types, the
Pathophysiology underlying the allergic conjunctivitis is not fully
understood. Great variety of available pharmacologic options is an
evidence of the complexity of the chemical reactions associated
with mast cell degranulation and mediator release causing the
onset of allergic signs and symptoms.
Allergic conjunctivitis is traditionally divided into five
categories, all of which result from a hypersensitivity reaction by
ocular tissues to one or more allergens.
(A) Mild, acute and transient allergies include:
Seasonal allergic conjunctivitis (SAC), and
Perennial allergic conjunctivitis (PAC).B) chronic allergic diseases with the potential for causing
significant ocular consequences include:
Giant papillary conjunctivitis (GPC),
Atopic keratoconjunctivitis (AKC), and
Vernal keratoconjunctivitis (VKC).
Atopic and vernal keratoconjunctivitis are potentially
vision-threatening conditions due to the risk of corneal ulceration,
vascularization, and scarring.
The cardinal feature of allergic conjunctivitis is itching,
other symptoms such as tearing, burning and foreign body
sensation may be present in variable degrees in all of these
conditions.
Diagnosis of allergic conjunctivitis is usually based on an
accurate history and a proper clinical examination. In some cases
clinical examination needs to be substantiated with laboratory
diagnostic methods, as skin tests, assessment of specific Ig.E and
conjunctival scraping.
SAC and PAC are recurrent conditions, but they are easily
controlled and do not typically result in permanent visual loss.
Likewise, GPC does not typically result in permanent visual loss.
On the other hand, VKC and AKC have sight-threatening
complications including corneal ulcers and potential side-effects
from the use of steroid treatment.
Management of allergic conjunctivitis depends on the
severity of the condition as well as medication cost and expected
patient compliance.Treatment includes:
(1) Non-specific medical therapy:
• Cold compresses: may be all that is necessary in mild seasonal
and perennial conjunctivitis.
• Mucolytic drops: dissolves the abnormal mucus.
• Treatment of facial eczema in AKC – lid margin hygiene.
(2) Vasoconstrictors
(3) Antihistamines – conventional topical antihistamine
(4) Oral antihistamine preferably non sedating
(5) Mast cell stabilizers
These compounds are used topically to reduce mast cell
degranulation, but also have a wide range of other antiinflammatory
effects that may be relevant. They are usually well
tolerated with very few side effects. They offer a preventative
action and work most effective if taken before the onset of
symptoms, where possible (e.g. at the beginning of the pollen
season) or early in the disease process. AS the onset of action is
slow (5-7 days) and stinging can occur, patient must be warned
that their eyes might feel worse to start with.
IN VKC and AKC, mast cell inhibitors act as steroid
sparing agents.
Cromolyn sodium is the longest established of these drugs.
And both 2% and 4% drops are available for use up to 4 times per
day. Nedocromil sodium is a newer, higher potency mast cell
stabilizer that compares favourably to cromolyn and can be used
twice daily in SAC and PAC.Lodoxamide is another recently introduced mast cell
stabilizer, which may evoke fewer stings than the other. Both
nedocromil and lodoxamide have a more rapid onset of action.
(6) Nonsteroidal anti-inflammatory agents
Topical NSAIDs appear to have some beneficial effects in
allergic conjunctivitis. Topical NSAID are not as potent as
steroids but have the advantage of good ocular safety profile and
useful in treating non sight threatening conditions like SAC and
PAC when mast cell stabilizers and antihistamines fail.
(7) Steroids
Topical steroids are very powerful in controlling allergic
conjunctivitis, but have potentially sight-threatening side effects.
Steroids are generally contraindicated in SAC & PAC;
occasionally they are used in AKC and VKC.
(8) Cyclosporine
Topical preparation of 2% cyclosporine has been shown to
provide a marked reduction in the symptoms and signs of VKC,
and cyclosporine is particularly helpful as a steroid-sparing agent.
(9) Immunotherapy
Allergen immunotherapy have been shown to be especially
beneficial in the treatment of allergic conjunctivitis, and are the
only therapy available that changes the underlying problem of
allergies, potentially curing the problem of eye allergies.
(10) Surgery
Usually limited to the treatment of the sight-reducing corneal
disease in AKC & VKC.