An allergy is a type I hypersensitivity disorder of the immune system in which the body reacts to a normally harmless substances called an ‘allergen’ by triggering an immune response releasing antibodies of the IgE (immunoglobulin E) class, most notably histamine. When this happens, it is called an ‘allergic reaction’.
Some examples of type I hypersensitivity disorder allergies include hay fever, asthma, eczema, food allergy, and anaphylaxis.
What are the symptoms of an allergic reaction?
Allergic reactions range wildly in severity. On one side of the scale, an allergic reaction may cause itchy and watery eyes, a runny nose, skin rash, stomach pain, coughing and wheezing, and sneezing; these symptoms may be present in hay fever, for example.
On the other side of the scale is anaphylaxis, or anaphylactic shock; it is the most serious form of allergic reaction and is treated as a medical emergency. Swelling of the face, lips, eyelids, tongue and throat, hives, vomiting, difficulty breathing, drop in blood pressure, and unconsciousness are all symptoms of anaphylaxis and if it goes untreated, it can prove fatal.
What are some common allergens?
Different people’s allergies are triggered by different allergens but all allergens have something in common; they all contain protein or bind with protein once in the body. When immune cells encounter the allergic protein, antibodies are produced; this reaction is similar to when the body detects foreign pathogens.
An allergen can be in food, mould, plants, chemicals, animal fur, dust mites, insect venom, medicines, and chemicals found in every day products.
Some common allergens include:
• Foods: Peanuts (groundnuts), tree nuts (pecans, walnuts, chews etc.), soya and sesame products, shellfish (shrimp, mussels, crabs), wheat, milk, fish, and eggs.
• Plants: Pollen from grass and plants.
• Insects: Venom from bees, ants, wasps, and ticks.
• Medicines: Penicillin and other antibiotics, barbiturates, insulin, anticonvulsants, and sulfa pdrugs.
• Animals: Fur and skin flakes from domestic pets like cats and dogs.
• Mould: Spores from alternaria, cladosporium, aspergillus, and penicillium moulds.
• Chemicals: Cleaners, colognes, shampoo, hair dye, and moisturisers.
What are the treatments available?
The treatment for allergies will depend on the severity. For things like hay fever and seasonal allergies, a few antihistamines should do the trick; they can be purchased over the counter from supermarkets and pharmacies.
For allergic (extrinsic) asthma, there is at this time no cure; the symptoms of asthma are managed. Treatments include inhalers, both relievers and preventers, which relax the muscles around the airways and reduce inflammation of the airways.
Although asthma has the potential to be a serious, life-threatening condition, anaphylaxis is the most serious allergy falling within type I hypersensitivity disorders. When someone goes into anaphylactic shock, they are usually treated by the administration of epinephrine (adrenaline) through an EpiPen. Epinephrine stops anaphylaxis by constricting blood vessels which, in turn, stops blood pressure from dropping, allows airways to relax, reduces swelling, and stops itching.
What causes someone to be susceptible allergic reactions?
It’s thought that genetics play a large role in determining whether or not someone develops allergies. When one parent has allergies, the offspring have a 33 percent chance of developing them. When both parents have allergies, there is a 70 percent chance.
Allergies begin with exposure. A person who has allergic tendencies may have inhaled an allergen many times before but at some point, for no particular reason, the body identifies it as a harmful intruder, readying itself for the next exposure by developing antibodies to attack next time it is detected.
How to avoid allergens or ‘triggers’
Because people can be allergic to many things that are quite abundant and unavoidable like pollen, prevention is the key when it comes to allergies. If you’re allergic to something like dog hair, for example, then don’t be around dogs. If you love your furry companion too much, then take antihistamines. If dust triggers asthma, then make sure your house or wherever you spend the majority of your time is as dust free as possible.
It’s also important that you are aware of your triggers. When you know what triggers your reaction, you can better equip yourself with the appropriate means to treat it or avoid it altogether. For instance, a common trigger for anaphylaxis is peanuts, so the best way to avoid going into anaphylactic shock would be to avoid peanuts and foods containing traces of peanuts.