First, let’s look at ocular allergies and how they may be managed.
An allergy is an inappropriate inflammatory reaction to foreign substances by the body’s immune system. Whereas it’s appropriate for the immune system to react to fight off parasites, bacteria or viruses, an inappropriate reaction to usually harmless substances like pollen, moulds, dust mites, etc, manifests itself as an allergy.
The substances that trigger an allergy are called allergens.
Immunoglobulin E (IgE) is an antibody that all of us have in small amounts. Allergic individuals, however, generally produce IgE in larger quantities. During a sensitisation period, an allergen causes the body to overproduce IgE, which coats cells such as mast cells and basophils; these contain various mediators, such as histamine. These coated cells are now primed, and ready to react to all subsequent exposures to the allergen, which leads cells to release the allergic mediators mentioned above (Type 1 reaction within minutes). These chemicals cause typical allergic symptoms, such as localised swelling, inflammation, itching, mucus production and even anaphylaxis (Figure 1).