Tingling or itching in the mouthSwelling of the lips, tongue, face, throat, or other body partsHives, itching, or eczemaWheezing, nasal congestion, or trouble breathingStomachache, diarrhea, nausea, or vomitingDizziness, lightheadedness, or faintingAnaphylaxis, a severe, life-threatening allergic reaction that can affect breathing and cause shock

PainRednessSwelling (at the sting site and sometimes other parts of the body)FlushingHivesItchingAnaphylaxis

Itchy skinHives — small red spots especially on the chest, back, or abdomen — or other rashesSwelling, particularly in the faceBreathing problemsAnaphylaxis

Itchy nose, mouth, eyes, throat, skin, or any body partDifficulty with smellRunny noseSneezingWatery eyes

Other symptoms may develop later, including:

Stuffy noseCoughingClogged ears and reduced ability to smellSore throatDark circles or puffiness under the eyesSleep disturbances, leading to fatigue and irritabilityHeadache

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. There are many things that can cause allergies. Some of the most common allergens include:

Pollen

Pets

Food

Mold

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.

Cockroaches

Dust Mites

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.

Latex

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

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). Your doctor may then recommend one or more of the following allergy tests:

Skin Tests

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.

Blood Test

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. You may be asked to eliminate certain foods from your diet and then consume them again to determine whether they’re problematic. Additional reporting by Lynn Marks.