There are many different types of allergies. Allergies occur when the immune system identifies a normally harmless substance as dangerous. This sets off a chemical reaction in the body. This reaction can cause uncomfortable and even dangerous symptoms.1
Allergic reactions may happen only when you are exposed to a substance, such as with a food, latex, or pet dander allergy. Sometimes, they can occur seasonally, such as with allergies to pollen. Or, an allergy to something like mold or dust mites can be year-round depending on where a person lives.1
The most common types of allergies are those to:1
- Food
- Latex
- Medicines
- Mold
- Pollen and plants
- Animals and insects
Food allergies
In the United States, food allergies affect about 4 to 6 out of every 100 children and 4 out of every 100 adults. Eight types of food account for 90 percent of food allergies. They include:2
- Milk
- Eggs
- Wheat
- Soy
- Peanuts
- Tree nuts
- Fish
- Shellfish
Allergic reactions to food may affect the skin, throat, stomach, intestines, heart, and breathing. Symptoms may include:2,3
- Vomiting or stomach cramps
- Hives
- Wheezing and difficulty breathing
- Throat tightening
- Trouble swallowing
- Swelling of the tongue
- Anaphylaxis, which is a severe, life-threatening allergic reaction
Animal and insect allergies
People can be allergic to a variety of animals and insects. Generally, people are allergic to what furry animals shed, which is called dander (skin flakes). The most common animals to cause allergic reactions are:4
- Cats
- Dogs
- Horses
- Hamsters, gerbils, and rats
- Rabbits
Many insects cause allergic reactions. The most common stinging or biting insects that people react to include:1
- Bees
- Wasps
- Hornets
- Yellow jackets
- Fire ants
People can also react to non-stinging insects. Two household pests, cockroaches and dust mites, are the most common cause of year-round allergy and asthma symptoms.1
Allergic reactions to animals and insects may include:1-4
- Vomiting or stomach cramps
- Hives
- Wheezing and problems breathing
- Throat tightening
- Trouble swallowing
- Swelling of the tongue
- Anaphylaxis
With insect stings, some people only get swelling at the site.1-4
Plant allergies
There are many plants that cause people with allergies to react. They may be allergic to the plant’s pollen or some chemical found in the plant itself.1-5
Pollen is one of the most common triggers of seasonal allergies. Seasonal allergies may be called hay fever or allergic rhinitis. Common causes include grasses, ragweed, pigweed, sagebrush, and trees like cedar and oak.5
Pollen allergies can cause:5
- Runny or itchy nose, eyes, and ears
- Sneezing
- Stuffy nose
- Red or watery eyes
- Swelling around the eyes
Coming into contact with certain plants can also cause an allergic reaction. Poison oak, poison ivy, and poison sumac are all plants that have urushiol, an oily sap. Your skin coming into contact with urushiol can cause an itchy rash. It can also be inhaled if the plant is burned.6
Latex allergies
Latex is a protein found in the sap of the Brazilian rubber tree. It is used in many everyday products, like bandages, gloves, balloons, toys, condoms, and rubber bands.8,9
If a person with a latex allergy touches one of these products or breathes in latex fibers, they may have symptoms like:8,9
- Itchy rash
- Sneezing
- Runny nose
- Wheezing
- Difficulty breathing
Some people with a latex allergy can develop an allergic reaction from breathing in latex fibers in the air.8,9
Drug allergies
Being allergic to a drug is different from having a reaction to a drug. Many people may have side effects while taking a drug. These side effects are caused by the chemical properties of the medicine and do not involve the immune system. Common side effects include stomach upset, headache, or weight gain.9
A drug allergy occurs when the immune system is over-sensitive to an ingredient of the medicine. The antibiotics penicillin, sulfa, and mycin are some examples of drugs people may be allergic to, but an allergy can develop to any drug. True drug allergies are rare. But when they happen, symptoms include:9
- Hives and other skin reactions
- Anaphylaxis