Allergy

An allergy is a reaction by your immune system to something that does not bother most other people. People who have allergies often are sensitive to more than one thing. Substances that often cause reactions are

  • Pollen
  • Dust mites
  • Mold spores
  • Pet dander
  • Food
  • Insect stings
  • Medicines

Normally, your immune system fights germs. It is your body's defense system. In most allergic reactions, however, it is responding to a false alarm. Genes and the environment probably both play a role.

Allergies can cause a variety of symptoms such as a runny nose, sneezing, itching, rashes, swelling, or asthma. Allergies can range from minor to severe. Anaphylaxis is a severe reaction that can be life- threatening. Doctors use skin and blood tests to diagnose allergies. Treatments include medicines, allergy shots, and avoiding the substances that cause the reactions.

Causes of allergies

An allergy develops when the body’s immune system reacts to an allergen as though it is harmful, like it would an infection.

It produces a type of antibody (protein that fights off viruses and infections) called immunoglobulin E (IgE), to fight off the allergen.

When the body comes into contact with the allergen again, IgE antibodies are released, causing chemicals to be produced. Together, these cause the symptoms of an allergic reaction.

Treating allergies

The best treatment for an allergy depends on which allergen is causing the reaction. In some cases, avoiding the substance is the most effective way of managing an allergy. Read more about preventing allergic reactions.

The main medical treatment for an allergy involves using medication to control the symptoms. If you experience severe allergic reactions (anaphylaxis) you may be prescribed an adrenaline injector. For severe cases of rhinitis, immunotherapy may be recommended.

Medication

Most treatments are available over the counter, but always ask your pharmacist or GP for advice before starting any new medication.