Allergies occur when a person’s immune system reacts to environmental irritants that are typically safe for most people. These irritants, called allergens, can be found in substances such as dust, mold, pollen, animals, food, insects, and certain drugs.
Allergic reactions
When an allergic individual is exposed to an allergen, their body creates antibodies called IgE that “attack” the allergen. This can lead to symptoms such as sneezing, coughing, watery or itchy eyes, and skin irritation.
Types of allergies
There are four main categories of allergens:
- Inhaled allergens are breathed in and can include things like pollen and pet dander.
- Contact allergens cause irritation when they come into direct contacts with the skin, such as certain fabrics or poison ivy.
- Ingestant allergens are consumed and can include foods like peanuts and shellfish.
- Injectable allergens can be insect bites or venom, as well as certain medications.
Allergy symptoms
Allergies can range from mild to severe, with symptoms ranging from a runny nose to anaphylaxis, a potentially life-threatening emergency that requires immediate medical attention.
Allergy Diagnosis
To diagnose allergies, a doctor may ask about a patient’s medical history, perform a physical examination, and conduct a skin test, patch test, or blood test to determine which allergens the patient is sensitive to.