Allergy symptoms can range from mild to severe, even life-threatening. Most allergies can't be cured, but treatments can help.
Allergies occur when your immune system reacts to a foreign substance — such as pollen, bee venom or pet dander — or a food that doesn't cause a reaction in most people.
Your immune system produces substances known as antibodies. When you have allergies, your immune system makes antibodies that identify a particular allergen as harmful, even though it isn't. When you come into contact with the allergen, your immune system's reaction can inflame your skin, sinuses, airways or digestive system.
The severity of allergies varies from person to person and can range from minor irritation to anaphylaxis — a potentially life-threatening emergency. While most allergies can't be cured, treatments can help relieve your allergy symptoms.
Allergy symptoms, which depend on the substance involved, can affect your airways, sinuses and nasal passages, skin, and digestive system. Allergic reactions can range from mild to severe. In some severe cases, allergies can trigger a life-threatening reaction known as anaphylaxis.
Hay fever, also called allergic rhinitis, can cause:
A food allergy can cause:
An insect sting allergy can cause:
A drug allergy can cause:
Atopic dermatitis, an allergic skin condition also called eczema, can cause skin to:
Some types of allergies, including allergies to foods and insect stings, can trigger a severe reaction known as anaphylaxis. A life-threatening medical emergency, anaphylaxis can cause you to go into shock. Signs and symptoms of anaphylaxis include:
You might see your health care provider if you have symptoms you think are caused by an allergy, and nonprescription allergy medications don't provide enough relief. If you have symptoms after starting a new medication, call the provider who prescribed it right away.
For a severe allergic reaction (anaphylaxis), call 911 or your local emergency number or seek emergency medical help. If you carry an epinephrine auto-injector (Auvi-Q, EpiPen, others), give yourself a shot right away.
Even if your symptoms improve after an epinephrine injection, you should go to the emergency department to make sure symptoms don't return when the effects of the injection wear off.
If you've had a severe allergy attack or any signs and symptoms of anaphylaxis in the past, make an appointment to see your health care provider. Evaluation, diagnosis and long-term management of anaphylaxis are complicated, so you'll probably need to see a provider who specializes in allergies and immunology.
An allergy starts when your immune system mistakes a normally harmless substance for a dangerous invader. The immune system then produces antibodies that remain on the alert for that particular allergen. When you're exposed to the allergen again, these antibodies can release a number of immune system chemicals, such as histamine, that cause allergy symptoms.
Common allergy triggers include:
You might be more likely to develop an allergy if you:
Having an allergy increases your risk of certain other medical problems, including:
Preventing allergic reactions depends on the type of allergy you have. General measures include the following:
To evaluate whether you have an allergy, your health care provider will likely:
If you have a food allergy, your provider will likely:
Your provider might also recommend one or both of the following tests. However, be aware that these allergy tests can be falsely positive or falsely negative.
If your provider suspects your problems are caused by something other than an allergy, other tests might help identify — or rule out — other medical problems.
Allergy treatments include:
Immunotherapy. For severe allergies or allergies not completely relieved by other treatment, your provider might recommend allergen immunotherapy. This treatment involves a series of injections of purified allergen extracts, usually given over a period of a few years.
Another form of immunotherapy is a tablet that's placed under the tongue (sublingual) until it dissolves. Sublingual drugs are used to treat some pollen allergies.
Some allergy symptoms improve with home treatment.
Clinical practice guidelines suggest that some people with allergic rhinitis may benefit from acupuncture.
For symptoms that could be caused by an allergy, see your primary health care provider. You might be referred to a provider who specializes in treating allergies (allergist).
Ask if you should stop taking allergy medications before your appointment, and for how long. For example, antihistamines can affect the results of an allergy skin test.
Make a list of:
Some basic questions to ask include:
Don't hesitate to ask other questions.
Your provider is likely to ask you questions, including: