Simple allergic conjunctivitis is a mild, non-specific allergic conjunctivitis
characterized by itching, hyperaemia and mild papillary response. Basically, it is an acute or sub acute urticarial reaction.
characterized by itching, hyperaemia and mild papillary response. Basically, it is an acute or sub acute urticarial reaction.
Etiology
It is seen in following forms:
1. Hay fever conjunctivitis. It is commonly associated with hay fever (allergic rhinitis). The common allergens are pollens, grass and
animal dandruff.
2. Seasonal allergic conjunctivitis (SAC). SAC is a response to seasonal allergens such as grass pollens. It is of very common occurrence.
3. Perennial allergic conjunctivitis (PAC) is a response to perennial allergens such as house dust and mite. It is not so common.
Pathology
Pathological features of simple allergic conjunctivitis comprise vascular, cellular and conjunctival responses.
1. Vascular response is characterised by sudden
and extreme vasodilation and increased
permeability of vessels leading to exudation.
infiltration and exudation in the discharge of
eosinophils, plasma cells and mast cells producing
histamine and histamine-like substances.
3. Conjunctival response is in the form of boggy
swelling of conjunctiva followed by increased
connective tissue formation and mild papillary
hyperplasia.
Symptoms include intense itching and burning sensation in the eyes associated with watery discharge and mild photophobia.
Signs. (a) Hyperaemia and chemosis which give a swollen juicy appearance to the conjunctiva. (b) Conjunctiva may also show mild papillary reaction.
(c) Oedema of lids.
Diagnosis
Diagnosis is made from : (1) typical symptoms and signs; (2) normal conjunctival flora; and (3) presence of abundant eosinophils in the discharge.
Treatment
1. Elimination of allergens if possible.
2. Local palliative measures which provide
immediate relief include:
i. Vasoconstrictors like adrenaline, ephedrine, and naphazoline.
ii. Sodium cromoglycate drops are very effective in preventing recurrent atopic cases.
iii. Steroid eye drops should be avoided. However, these may be prescribed for short duration in severe and non-responsive patients.
3. Systemic antihistaminic drugs are useful in acute
cases with marked itching.
4. Desensitization has been tried without much
rewarding results. However, a trial may be given
in recurrent cases.
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