An allergy is an adverse reaction that the body has to a particular food or substance in the environment. Most substances that cause allergies are not harmful and have no effect on people who are not allergic.
Symptoms
The severity of allergies varies from person to person and can range from minor irritation to anaphylaxis — a potentially life-threatening emergency.
- Red watering eyes
- Runny nose, sneezing, obstruction, itching
- Shortness of breath, wheezing
- Abdominal pain, bloating
- Skin rashes, hives, angioedema
- Vomiting, diarrhea
Causes
- An allergy develops when the body’s immune system reacts to an allergen as though it is a threat, like an infection. It produces antibodies to fight off the allergen, in a reaction called the "immune response".
The next time a person comes into contact with the allergen, the body "remembers" the previous exposure and produces more of the antibodies. This causes the release of chemicals in the body that lead to an allergic reaction.
- Pollen, dust
- Food: shellfish, peanut, strawberries
- Insect stings: bee, wasp
- Drugs: penicillin, antiepileptics
- Latex
Diagnosis
- Skin prick test, patch test
- Blood: serum IgE level, RAST
- Allergen challenge test
Preventions
- Avoid exposure to known allergens
- Avoid such foods
- Change of town for seasonal hay fever
- Regular dusting of carpet, use of light furniture
Risk Factors
- Family history
- Asthma
- Children are more prone
Complications
- Anaphylaxis
- Recurrent sinusitis, pneumonia, ear infections
- Asthma
Treatment
- Antiallergics: Over the counter drugs like cetirizine fexofenadine can be used
- Anaphylaxis: treated with epinephrine (epipens should be carried at all times)
- Immunotherapy
