Overview of Allergies
An allergy is an immune reaction to a foreign substance, called an allergen, that is not otherwise harmful. The reaction is quick and predictable. Common allergens are pollen, insect stings, and pet dander. Reactions include hives, sneezing, and asthma attacks.
Your body produces antibodies to protect you from illness and infection. When you make antibodies that incorrectly identify something as harmful, it causes inflammation of your skin, sinuses, airways, or digestive system.
The severity of allergic reactions varies from mild to anaphylaxis, a life-threatening emergency. Allergies can't be cured, but there are effective treatments that mitigate their symptoms.
- Atopic dermatitis, or eczema, causes itchy, red, flaking, or peeling skin.
- Contact dermatitis, such as from latex, or poison ivy, oak, or sumac, causes a rash, with redness, itching, swelling, and blisters. In severe cases, the rash may continue to break out in new areas for several days, so that it seems to be spreading, although this is probably due to the amount of exposure.
- Allergy to insect stings, most commonly from bees and wasps, can cause an area of swelling at the sting site, itching and hives over your entire body, coughing and respiratory distress, and anaphylaxis
- Allergic rhinitis, or hay fever, may result in sinus congestion and a runny nose, itchy eyes and nose, and swollen, watery eyes
- Food allergies may cause a tingling mouth, swelling of the lips, tongue, face, and throat, hives, and anaphylaxis
- Drug allergies have a wide variety of symptoms, like hives, itchy rash, facial swelling, respiratory distress, and anaphylaxis.
Anaphylaxis is an extremely severe, life-threatening, allergic reaction, characterized by:
- Swollen airways
- Severe shortness of breath
- Rapid, weak pulse
- Loss of consciousness
You should see your WellStar physician if you have allergic symptoms, especially if they seem to be in response to something new in your environment. If the symptoms occur after you start a new medication, call the prescriber immediately.
When your immune system detects a harmful organic invader, it custom-builds antibodies, called IgE, that will bind to the particular proteins in that invader. The IgE circulates through the bloodstream and binds to a receptor on the surface of other immune cells, called mast cells and basophils. These cells will react to future contact with the invader, releasing histamines and other inflammatory chemicals, which cause widening of blood vessels, production of mucus, nerve stimulation, and other effects.
When this reaction mistakenly takes place in reaction to a normally harmless substance, it is called an allergy. These allergic reactions can be very severe.
Common allergic triggers are:
- Latex, causing a topical (skin) reaction
- Urushiol, an oil (not a protein) found on poison ivy, oak, and sumac. Not itself a protein, urushiol alters proteins in the skin that make them foreign to the immune system, leading to swelling and a rash.
- Foods, especially peanuts. Peanut allergies may be particularly severe, triggered by minute traces of peanut proteins. Tree nuts, like pecans and walnuts, seeds, and their oils, also contain proteins that may cause allergic reactions. Egg allergies, usually to the white, not the yolk, affect about two percent of children, but are frequently outgrown. Wheat, soy, fish, shellfish, dairy products may also be allergens, although lactose intolerance is not an allergic reaction.
- Airborne protein carriers, like pollen, animal dander, dust mites, and mold
- Insect stings, like bee and wasp stings
- Medications, especially penicillin and related antibiotics
Some risk factors for developing an allergy are:
- Family history of allergies
- Being a child (IgE levels are at their highest among children)
- Have asthma or other allergies