Allergic Conjunctivitis

Page 1 2 3

What is Allergic Conjunctivitis?

This animation brought to you by Blausen Medical Communications.
Contact Andrew Walbank.

'Conjunctivitis' means inflammation of the conjunctiva, which is the thin membrane covering the white part of the eye. 'Allergy' means an exaggerated reaction towards a certain substance that does not occur in normal individual. Put together, it is an inflammation of the conjunctiva due to an allergic reaction. Allergic conjunctivitis is part of the ocular allergy disorders. Generally ocular eye disorders include many other allergic diseases of the eye.

Allergic conjunctivitis can be divided into 3 types depending on the pattern of disease:

acute allergic conjunctivitis
seasonal allergic conjunctivitis
perennial allergic conjunctivitis

These 3 entities are commonly known as 'allergic conjunctivitis'. They represent the common forms of ocular (eye) allergy, and they are the ones to be discussed here.

Who gets Allergic Conjunctivitis?

Allergic conjunctivitis is common. It is generally a disease of young adults. Ocular allergy (where allergic conjunctivitis is part of it) is estimated to affect 20% of the population every year. Also, like allergic rhinitis (including hay fever), the cases of allergic conjunctivitis are increasing worldwide.

Predisposing Factors

Allergic conjunctivitis is associated with other allergic diseases, such as:

Allergic Rhinitis (hay fever)

skin allergies, including allergic dermatitis (atopic eczema)

asthma

Progression

Allergic conjunctivitis, although divided into 3 clinical subtypes, runs on the same biochemical pathway in the body. Common allergens include pollens, grasses, trees, weed, mould, animal furs, dust mites, etc.

Acute allergic conjunctivitis is typified by the following features:

exposure to environmental allergens

immediate allergic reactions to exposure, leading to signs and symptoms

resolve of symptoms in less than 24 hours, regardless of treatment

Seasonal allergic conjunctivitis can have the following features:

it is known by other names, such as hay-fever type conjunctivitis or allergic rhinoconjunctivitis

it is associated with allergic rhinitis (hay fever)

like the name suggests, it is usually due to allergic reaction to pollens and grasses, hence it commonly occurs during spring and late summer. This subtype typically lasts for several months

Perennial allergic conjunctivitis have the following features:

it is a mild, chronic conjunctivitis usually due to all-year round allergens such as dust mites, mould, animals especially pets

like the name suggests, it has no fixed period in the year in which it occurs. The Anatomy and Physiology of Allergy.

Page 1 2 3