Allergic Conjunctivitis

Clinically known as periorbital puffiness, puffy or sore eyes is a common symptom with many possible causes, including ocular (eye) allergy. Puffy eyes mean a swelling in the tissues around the orbit of the eyes. Sore eyes are not the same as 'bags under the eyes'. The symptoms of allergic eye disease include:

• Sore eyes
• Puffiness
• Redness of the eyes
• Itching
• Discharge
• Watery eyes
• Sensitivity to light (photophobia)

Allergies are one of the most common causes of sore eyes. Exposure of the eyes to an allergen like pollen, pet dander or mould causes an over-reaction in the immune system. One major component of this reaction is the release of a chemical called histamine from mast cells, a type of immune cell. Histamine has various effects, one of which is to make tiny blood vessels around the eye swell and become leaky, thereby releasing fluid into the surrounding tissue and causing swelling.

Three of the main types of ocular allergy all have similar symptoms and all come under the heading of conjunctivitis, sometimes known as 'pink eye'. The conjunctiva is the outermost layers of tissue covering the eye itself and the inside of the eyelids. The allergic response described above also causes inflammation in the conjunctiva, as well as puffiness in the tissue around the eye. The three types of allergic (sometimes also known as atopic) conjunctivitis are:

• Seasonal allergic conjunctivitis: This is really a form of hay fever, in which ocular, rather than nasal, symptoms predominate. It is the most common form of allergic conjunctivitis, occurring mainly in spring and summer and caused by exposure to pollen. An allergy to mould may produce seasonal allergic conjunctivitis in the autumn months when there are more mould spores around. Both eyes are usually affected.
• Perennial allergic conjunctivitis: Less common than the seasonal condition, in the perennial form of allergic conjunctivitis, symptoms like puffy eyes occur all year round. The person often also suffers from eczema. The cause is an allergen that is present all the time such as; house dust mite, followed by animal (cat or dog) dander. Both eyes are usually affected.
• Acute allergic conjunctivitis: This condition normally affects just one eye. Symptoms come on very rapidly and are often caused by exposure to ragwort pollen. Symptoms can be quite dramatic, with a lot of swelling. Symptoms soon clear up once the trigger is removed.

There are non-allergic causes of sore eyes, these include:

• Lack of sleep
• Conditions causing fluid retention, such as pregnancy and excess salt in the diet
• Crying, when the salt in tears leads to fluid retention
• Dysfunction of the tear glands

Airborne allergens like pollen, mould or dust often cause eye problems. Pollen grains are readily deposited on the surface of the conjunctiva because of their size and shape. However, some people are allergic to other substances, such as the ingredients in eye makeup or contact lens solutions.