An allergy is caused when the immune system reacts to something that is usually harmless. When the patient comes into contact with the trigger that they inhale, swallow or touch, their body releases a protein called IgE to attack the allergen and along with that get released histamine and other chemicals. These chemicals and proteins released in the blood by the patient's body, although acting as a defence mechanism, cause the symptoms of allergies.
- Respiratory: Pollen is the most common reason for allergic rhinitis or hay fever. Dust, animal dander from house pets, strong odours such as perfumes, mould or atmospheric pollution can cause respiratory allergies.
- Skin allergies: Insect stings, mosquito bites are ticks bite allergies are all very common. Hives or sun exposure is another form of skin allergy. Leather belts, detergent, jewellery (made from nickel), certain medications and cosmetics can also react with the skin and can lead to allergies as a side-effect.
- Food allergies: Peanuts, eggs, shell fish, soy, wheat, milk are some of the common food allergens. Preservatives present in food items may also lead to allergies.