The Science of Allergies: Causes, Symptoms, and Treatment Options

For many people, allergic reactions to environmental sources can cause serious discomfort and health complications. Allergies are the sixth leading cause of chronic illness in the United States and effect up to 30 percent of adults and 40 percent of children. Knowing the science behind allergies can help in understanding the cause, recognizing the symptoms, and exploring the various treatment options.

What are Allergies?

In order to understand allergies, it’s important to first understand the science behind them. Allergies can be described as an over-reactive immune system response to an allergen, or any type of environmental stimulus that the body views as a foreign invader. When the body identifies an allergen, it releases a chemical called histamine which causes uncomfortable symptoms like hives, sneezing, and itching. This immune system response is called an allergic reaction.

Common Allergens

Allergens come in many forms ranging from food and pollen to pet dander and dust mites. Here are some of the most common allergens that cause reactions:

• Pollen: This may be the most common because it tends to be small enough to be inhaled. Pollen exist in flowers and trees, and the type of plant matters. For example, trees cause more reactions in the spring, while grasses cause reactions in the summer.

• Animal Dander: This is composed of tiny skin cells that are shed from cats and dogs. These cells carry pet allergens that cause reactions once they’re inhaled.

• Dust Mites: This allergen is found in house dust, which can cause reactions if it’s inhaled.

• Mold: Mold loves warm and damp environments, which means it’s often found in bathrooms and basements. Eating or inhaling mold spores can cause an allergic reaction.

• Food: Reactions can be caused by certain foods, particularly shellfish, nuts, and dairy.

Symptoms of Allergies

When an allergen has been inhaled, ingested, or touched, the body will have an allergic reaction and the person may experience a variety of different symptoms. Common symptoms for environmental allergies include:

• Sneezing and nasal congestion

• Itchy nose, eyes, throat, and mouth

• Wheezing and difficulty breathing

• Watery, itchy, and red eyes

• Rashes, hives, and itching

• Swelling or tingling feeling in the mouth or throat

• Abdominal cramping, nausea, and vomiting

• Headache or dizziness

Types of Allergy Treatment

The different types of treatment for allergies depend largely on the cause of the reaction and the severity of the symptoms. The two main treatments for allergic reactions are medication and immunotherapy, which are designed to treat the symptoms of the allergy and to lessen the severity of the allergic reaction.


The most common type of allergy therapy involves medications. Over-the-counter antihistamines can help reduce the symptoms of an allergic reaction, such as itching and sneezing. Corticosteroids are often prescribed for more severe cases, as they reduce inflammation and other allergic symptoms caused by the release of histamine.


Also known as desensitization, immunotherapy entails exposing the body slowly to a tiny amount of the allergen over a period of time. Over time, the body may become less reactive to the allergen and have fewer or milder reactions. Immunotherapy is most often used to treat pollen and dust mite allergies.

Allergies are a common condition that affects millions of people each year. The science behind allergies can help in understanding what causes them, recognizing the symptoms, and exploring the various treatment options available. Depending on the cause, allergies can be treated with either medication or immunotherapy. By understanding the causes and symptoms of allergies, and seeking appropriate treatment options, people can mitigate the effects of their allergies and live healthier lives.