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Ocular Allergies- Classification, Signs and symptoms, Pathogenesis, Treatment,
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OCULAR ALLERGYCCDH MEETING
MARCH 2014
Dr Michael Minogue
CLASSIFICATION
acute conjunctival allergy seasonal allergic conjunctivitis perennial allergic conjunctivitis vernal kerato-conjunctivis atopic kerato-conjunctivis giant papillary conjunctivitis contact allergic conjunctivis
SYMPTOMS
itch conjunctival hyperaemia tearing conjunctival oedema mucus discharge lid oedema photophobia eye rubbing blurred vision
SEASONAL ALLERGIC CONJUNCTIVITIS
sub-acute onset lasts days to weeks seasonal allergens- grass, tree pollens, moulds associated with hay-fever/allergic rhinitis IgE mediated, type 1 allergic response 80% of patients are under 30 years of age strong personal or family history of allergy affects 5 to 20% of population
Cytokine regulation of the acquired immune response
ACUTE CONJUNCTIVAL ALLERGY
sudden onset eg allergy to cats self limited- usually settles within 24hrs conjunctival and lid oedema can be alarming
to patient
PERENNIAL ALLERGIC CONJUNCTIVIS
persistent symptoms but can have seasonal spikes
triggered by house-dust mites,moulds,animal allergens
IgE mediated mostly young adults (slightly higher prevalence
in males often personal or family history of allergy
VERNAL KERATOCONJUNCTIVITIS
a disease with some allergic components in combination with a chronic inflammatory response
comprises 2% of cases of ocular allergy mostly affects young boys under 10 years of
age most common in hot climates tarsal (cobblestone papillae) and limbal
(trantas dots) variants personal or family history of atopy in 50% positive skin test in only 50%
Upper tarsal conjunctiva of patient with VKC
PATHOPHYSIOLOGY
1. Th2 lymphocytes mediate hyperproduction of IgE via Il4 . They also mediate differentiation and activation of mast cells and eosinophils via Il3 and Il5 respectively.
2. Over-expression of oestrogen and progesterone receptors in the conjunctiva of VKC patients may explain improvement with onset of puberty.
3. There may be involvement of neural factors such as substance P and NGF in pathogenesis
4. Hypersensitivity to wind, dust, sun may have a role.
5. Probable genetic component - a reduced level of tear film histaminase has been found.
CLINICAL FEATURES OF VKC
giant papillae/ trantas dots ropy mucus discharge common SPK and shield ulcers may be related to
epithelial toxic effects of eosinophilic major basic protein, eosinophilic cationic protein and peroxidase
ptosis can occur steroid induced glaucoma and cataract can
occur
ATOPIC KERATOCONJUNCTIVITIS
associated with atopic eczema often periocular with lid margin involvement male predominance, age 30-50 often strong family history of allergy (atopic
eczema an asthma) can have associated ocular surface disease
(conjunctival scarring, corneal PEK, corneal vascularization)
herpetic keratitis can occur in 15% of patients
keratoconus can occur in 5-15% of patients affects 3% of population
Severe periocular and lid involvement of AKC
ATOPIC KERATO-CONJUNCTIVITIS (CONT.)
eyelid skin thickened with lichenification can have associated punctal ectropion/ ptosis lower fornix conjunctival papillae potential visual loss from corneal disease,
cataract, steroid, induced glaucoma type I and type IV hypersensitivity increased mast cells, eosinophils, CD4+ T cells
(Th1 and Th2), monocytes, fibroblasts
Limbal gelatinous hyperplasia in AKC
GIANT PAPILLARY CONJUNCTIVITIS
non infectious inflammation disorder of the superior tarsal conjunctiva
named for size of papillae (> 1mm in diameter)
papillae > 0.3 mm are considered abnormal occurrence 1 to 5% of soft contact lens
wearers, 1% of hard contact lens wearers average time of onset is 8 months for soft
contact lens wearers can occur secondary to exposed sutures,
elevated subepithelial calcium plaques, ocular prosthetics
often associated history of atopy
Giant papillary conjunctivitis Advancing conjunctival thickening and papillary formation
Giant papillae
SYMPTOMS AND SIGNS
early - mild irritation, scanty mucus discharge
late - blurred vision secondary to lens coating
with mucus and protein - increased mucus accumulation - persistent protein body sensation - ocular itching after contact lens removal - complete contact lens intolerance
PATHOGENESIS
probably due to combined effect of mechanical trauma followed by repeated immunological presentation of foreign antigens in the form of surface deposits or environmental agents
combined type I and type IV hypersensitivity reactions
infiltration of conjunctival substantia propria by eosinophils, mast cells (T cell independent, skin type), basophils, lymphocytes and plasma cells
TREATMENT
removal of cause change to daily wear contact lenses of RGP
lenses hydrogen peroxide disinfection probably best more frequent enzymatic cleaning of soft
lenses topical corticosteroid in acute phase (along
with contact lens discontinuation) good prognosis
TREATMENT
1. non specific allergen avoidance air conditioning cold compresses cold artificial tears
2. topical or oral antihistamines eg OTC Naphazoline-Antazoline
3. combined antihistamine / mast cell stabilizers Olapatadine (Patanol)- preservative BAK Ketotifen (Zaditen) – preservative free
4. mast cell stabilizers Cromoglycate (Opticrom) Lodoxamide (Lomide)
TREATMENT (CONT.)
5. topical steroid FML Maxidex Prednefrin Forte
6. calcineurin inhibitors Cyclosporine (Restasis) Tacrolimus
7. systemic immuno supression oral Prednisone oral Cyclosporine
8. Plasmapheresis
QUESTIONS1. Which of the following symptoms is associated with ocular allergy?
a. itch
b. tearing
c. conjunctival hyperaemia
d. all of the above
2. Which of the following drug is not generally used in the treatment of
conjuctival allergy?
e. topical antihistamine / mast cell stabilizer
f. topical steroid
g. topical calcineurin inhibitors
h. NSAIDS
3. Which of the following can be associated with AKC and VKC?
i. keratoconus
j. bacterial keratitis
k. glaucoma
l. cataract
m. all of the above