Anyone can have or develop allergies, which are the sixth leading cause of chronic illness in the United States, per the American College of Allergy, Asthma, and Immunology (ACAAI).
As common as allergies are, diagnosing them isn’t always simple.
Diagnosis of allergies involves several factors such as identifying an individual’s symptoms and when they occur, reviewing family and medical history, undergoing a physical examination, and testing.
Allergies can cause a range of symptoms. Your signs and symptoms will depend on the type of allergy you have. You may also react differently to the same allergen at different times.
- Tingling or itching in the mouth
- Swelling of the lips, tongue, face, throat, or other body parts
- Hives, itching, or eczema
- Wheezing, nasal congestion, or trouble breathing
- Stomachache, diarrhea, nausea, or vomiting
- Dizziness, lightheadedness, or fainting
- Anaphylaxis, a severe, life-threatening allergic reaction that can affect breathing and cause shock
- Swelling (at the sting site and sometimes other parts of the body)
- Itchy skin
- Hives — small red spots especially on the chest, back, or abdomen — or other rashes
- Swelling, particularly in the face
- Breathing problems
- Itchy nose, mouth, eyes, throat, skin, or any body part
- Difficulty with smell
- Runny nose
- Watery eyes
Other symptoms may develop later, including:
- Stuffy nose
- Clogged ears and reduced ability to smell
- Sore throat
- Dark circles or puffiness under the eyes
- Sleep disturbances, leading to fatigue and irritability
If you suspect you have allergies, keep a record of your symptoms, including when they start and what seems to trigger them. Information about potential allergy triggers will help your doctor when taking your medical history.
The reason why people’s allergy symptoms are triggered by different things (allergens) has to do with certain antibodies produced by the body’s immune system.
They set off a cellular chain reaction resulting in an allergic reaction. Each type of IgE has a “radar” for a specific allergen, so the allergic reaction is a response to that particular trigger.
There are many things that can cause allergies. Some of the most common allergens include:
These allergies typically occur in early spring, summer, and fall, but can occur at different points in the year depending on weather conditions and where you live.
While some breeds may be more allergy-friendly than others, there is no such thing as a hypoallergenic dog or cat.
Mold spores (which are even smaller than pollen) are released into the air, where they spread via wind or humidity and can be inhaled.
Although there are many types of mold, only a few cause allergies. When found indoors (usually in bathrooms, kitchens, and basements), they can cause allergy symptoms year round.
Insect Bites and Stings
Most people recover from an insect bite or bee sting in a matter of hours or days with minor pain, itching, and swelling at the site.
Fortunately, most biting insects, such as mosquitoes or fleas, rarely cause extreme reactions.
In rare cases, latex can cause hives, difficulty breathing, or even anaphylaxis.
Less than 1 percent of Americans have a latex allergy. It’s more common among healthcare workers and others who regularly wear latex gloves. Individuals who have undergone multiple surgical procedures over their lifetime, especially children with spina bifada, are at increased risk as well. Synthetic latex found in paint does not cause allergies.
Medication can cause both allergic and nonallergic reactions. Allergic reactions can be mild (such as a skin rash or nasal symptoms) or life-threatening (anaphylaxis).
To diagnose allergies, your doctor will first review your medical and family history. A physical examination, which may include an X-ray or lung function test, can also help spot allergy signs or symptoms.
Your doctor may then recommend one or more of the following allergy tests:
They are not recommended for people who have had severe allergic reactions or take certain medications such as antihistamines, which can interfere with the results.
Skin prick tests (also known as puncture or scratch tests) involve applying drops of sterile allergen extract to the skin (usually the arm or the back), which are then pricked into the skin with a needle or lancet.
Approximately 50 allergens can be tested for at once. If the patient is allergic to one of the substances, a red, itchy bump (wheal) develops at the site.
In some cases, particularly when testing for allergies to penicillin or insect venom, the allergen may be injected into the skin on the arm (known as an intradermal test).
A patch test may be used when testing for allergens that cause skin irritation or rashes (also called contact allergy). Instead of pricking or injecting the skin, patches are worn for a period of time on the back to expose the skin to potential allergens.
A total IgE test measures the overall number of IgE antibodies in the blood, and an elevated result may indicate an allergic sensitivity. A specific IgE test measures the level of IgE antibodies in response to individual allergens, and it can help identify a specific allergy.
If you’re suspected of having a food allergy, your doctor may suggest keeping a diary of symptoms and triggers to identify the foods that are causing your reaction.
You may be asked to eliminate certain foods from your diet and then consume them again to determine whether they're problematic.
Known as an oral food challenge, this is done under strict medical supervision.
Additional reporting by Lynn Marks.