Types of Allergies

All allergens are not the same, and a person’s reaction may vary in degree of seriousness. When consulting an allergist you will be tested for different allergens, and the best treatment plan will be determined by the allergist.  

The most common allergens responsible for allergic reactions are:

Seasonal Allergy

If you find yourself sneezing or coughing during certain times of the year, you may suffer from seasonal allergies. Across the United States, trees bloom during the spring. Tree pollen season lasts from the end of February until early June, followed by grass season in the summer. In the fall, many people suffer with ragweed and weed allergies.

Drugs and Medications

Reactions to medications are relatively common. However, there are varying degrees to these reactions. One person may develop a rash and/or swelling while another may develop difficulty breathing. Typically, 5-10 percent of drug reactions are due to an allergic reaction to the medication. The drugs that cause the most common reactions are: antibiotics (penicillin), aspirin/nonsteroidal anti-inflammatory medications, chemotherapy, monoclonal antibody therapy, and anticonvulsants. The risk of developing a drug allergy increases when you take the medication frequently, if the medication physically touches your skin, or is given through injection.  


Most food allergies develop in childhood, though food allergies can also develop as an adult. The foods responsible for most food allergies in adults are: fish, peanuts, shellfish, tree nuts. Food allergies are not the same as food intolerances. In food allergies, the immune system overreacts to a protein found in food. Allergic symptoms can appear immediately after ingesting the food. Allergic reactions to food can be life-threatening. People with food allergies must be extra careful to avoid the food to which they are allergic to.


Latex is less common than it was in the past. Latex can be found in rubber gloves, condoms, balloons, toys, and rubber bands. It is a substance produced by rubber trees and blended with chemicals during the manufacturing process that gives it elasticity.

Nearly 50 percent of people with latex allergy also suffer from another allergy. Some patients with a latex allergy also have allergies to fruits and vegetables like bananas, avocado, tomatoes, or chestnuts can cause reactions in people sensitive to latex. Latex allergy can range from mild to severe. Allergic reactions can worsen with continued exposure. Latex allergies can be diagnosed by an allergist.


There are hundreds of mold types, but not all of them cause allergy symptoms. Molds are the tiny fungi spores that can be found present in the air. Mold flourishes in damp environments and can be found in houses or other buildings and outside. Everyone comes in contact with the spores that float through the air. But not everyone has a reaction to mold. Allergic reactions to molds can cause coughing, itchy eyes, congestion, and other allergy symptoms that make you feel awful. Mold allergies have been linked to asthma worsening, and consistent exposures to them can restrict airways and cause difficulty in breathing. Alternaria, Aspergillus, Cladosporium, and Penicillium are the most common allergy-causing molds.

Pet Dander

Allergies to pet are common. Cat allergies are more common than dog. The source of the allergen from cats and dogs are their saliva, urine and dander, not their fur.

Pet dander is the tiny flakes of skin from pets that shed. Typically associated with cats and dogs, animal dander can come from any animal with fur. An allergic reaction to pet dander includes sneezing, runny nose, wheezing, difficulty breathing, and in worse cases this can trigger asthma symptoms. It’s best to avoid exposure to the animal that triggers your allergies as much as possible. People with a pet dander allergy who come in direct contact can develop a skin reaction called dermatitis.

Venom (Stinging Insect)

Most people develop swelling, redness, and itching when they’ve been stung by an insect. A person allergic to venom experiences more severe symptoms since their immune system over reacts to the venom. If you are stung by an insect, your body produces antibodies called immunoglobulin E (IgE). If you are stung again by the same kind of insect, the IgE reacts to the venom and triggers an allergic reaction. A very small number of people have a life-threatening reaction to venom. In severe cases, a person can develop anaphylaxis <Link to: Anaphylaxis page> which requires immediate attention. Anaphylaxis is a severe, life-threatening allergic reaction. If you develop anaphylaxis symptoms after an insect bite, seek immediate medical attention.