Treating Environmental Allergies

Reviewed by: HU Medical Review Board | Last Reviewed: September 2022

Allergies sometimes develop when the immune system overreacts to something in the environment. This could be when the body has a negative reaction to something indoors, such as dust, or something outdoors, like pollen.

This reaction is called sensitization. Indoor and outdoor allergens usually do not cause a reaction in most people. But in some people, mold, pollen, dust, dust mites, or cockroaches trigger a reaction. Reactions may include:1-3

  • Stuffy or runny nose
  • Itchy or watery eyes
  • Itchy mouth, nose, ears, or throat
  • Hives

The first line of managing environmental allergies is always avoidance. Avoiding what allergens you can helps reduce symptoms. It may also allow you to take less medicine or even no medicine. But when avoidance is not enough or possible, there are many types of drugs to help control your symptoms.1-4

Seasonal versus chronic allergy treatment

Some people have allergies year-round. Others only have allergies during certain seasons. It is also possible to have both kinds of allergies. For example, you might have symptoms year-round, but worse during pollen season.1,2

Seasonal allergies are caused by airborne allergens like mold spores or pollen from grasses, trees, or weeds. People with year-round allergies are typically allergic to things like dust mites, pet dander, cockroaches, and mold.1-3

Whether allergy drugs are taken seasonally or year-round, treatment goals include the ability to:1

  • Work or go to school
  • Sleep through the night
  • Enjoy normal activities of life

Avoidance is the treatment of choice

The primary treatment approach with all environmental allergies is to avoid the allergens triggering symptoms whenever possible. Making some lifestyle and behavioral changes can help you manage exposure. It is also free. Some ways to avoid allergens include:1,3

  • Keep windows closed to keep pollen out
  • Use air conditioning in your home and car instead of opening the windows
  • Wear sunglasses outdoors to protect your eyes from pollen
  • Cover mattress and pillows with dust mite covers
  • Use a dehumidifier to reduce mold, mildew, and dust mites
  • Wash hands often and bathe/shower daily to wash off allergens
  • Change your clothes as soon as you come indoors to prevent pollen from spreading in the home

Symptom-based treatment

You may still have allergy symptoms after taking steps to avoid or minimize exposure to the allergens that affect you. You may need to take medicines to treat your symptoms. The most common symptoms of respiratory allergies include:2,3

  • Runny nose
  • Stuffy nose due to blockage or congestion
  • Sneezing
  • Itchy eyes, nose, mouth, ears, or skin
  • Fatigue resulting from poor sleep
  • Postnasal drip
  • Cough

Allergy drugs

There are many drug choices available to help reduce the symptoms of environmental allergies. They may bring short-term or long-term relief. Allergy drugs come in many different forms, including:2,4

  • Pills, capsules, and tablets
  • Liquids
  • Nasal sprays
  • Eye drops
  • Shots

Some are available over-the-counter in your local drug store or supermarket. Others require a prescription. Treatment options include:3,4

  • Antihistamines
  • Decongestants
  • Steroid nasal sprays (corticosteroids)
  • Leukotriene receptor antagonists (LTRAs)
  • Mast cell stabilizers (cromolyn sodium)
  • Allergy shots or sublingual (under-the-tongue) immunotherapy
  • Epinephrine


Antihistamines are oral and nasal drugs that block the effects of histamines. Histamines are chemicals produced by the body during an allergic reaction. These drugs treat symptoms including:1-4

  • Runny nose
  • Itchy or watery eyes
  • Hives
  • Swelling

They are less effective for nasal congestion. Some antihistamines may cause drowsiness. The newer antihistamines are less sedating. They come in tablet or capsule form, as well as eye drops and nasal sprays.1-4


Decongestants are oral or nasal medicines used to reduce nasal congestion. They work by constricting blood vessels in the nasal passages. This reduces the swelling that makes your head, nose, and face feel stuffy.2,4

Side effects of oral decongestants include:2,4

  • Insomnia
  • Irritability
  • High blood pressure
  • Heart palpitations

Prolonged use of decongestant nasal sprays can cause rebound congestion. This is a condition that develops when you use decongestants more than 3 days in a row. It causes worse congestion.2,4

Steroid nasal sprays

Steroid nasal sprays (corticosteroids) treat some kinds of allergies by reducing swelling and inflammation. An oral form can be used for severe symptoms, but the nasal spray is most effective for a stuffy, itchy, runny nose and sinuses.1

Nosebleeds are a common side effect of nasal sprays.1

Leukotriene receptor antagonists

LTRAs are oral pills used to treat both allergy and asthma symptoms. They work by blocking the action of chemicals in the body called leukotrienes. These chemicals cause allergy symptoms like nasal congestion, runny nose, and sneezing. LTRAs make it easier for people with allergies and asthma to breathe.4

In some people, LTRAs can lead to mood or behavior changes.4

Mast cell stabilizers

Mast cell stabilizers (cromolyn sodium) are a type of drug that help prevent mast cells from responding to specific allergens. These drugs come as pills, eye drops, or nose sprays. The nose spray can be used before exposure to allergens or as a maintenance drug.2,4

Allergy shots and under-the-tongue pills

Allergy shots and sublingual (under-the-tongue) therapy are types of immunotherapy. Immunotherapy gradually exposes the body to small amounts of certain allergens to help reduce the body’s allergic response over time.1,4

This is a treatment recommended for those who do not respond well to other treatments, have undesired side effects from drugs, or wish to have more permanent relief from their allergies. This treatment uses shots or pills under the tongue and can last for a few years. It is the most expensive and time-consuming treatment option, but it can bring long-term relief.1,4


Epinephrine is an important drug used to treat the most severe type of allergic reaction, anaphylaxis. It comes in premeasured amounts in an auto-injector device, such as EpiPen®. However, it is rarely needed for environmental allergies.1,2

Things to know

These are not all the possible side effects of allergy drugs. Talk to your doctor about what to expect when taking any allergy medicine. You also should call your doctor if you have any changes that concern you when taking these drugs.

Some drugs or supplements may interfere with each other. This means both drugs may work less well, or you may have serious side effects. Some medicines should also be used with caution in certain health conditions.

Before starting any allergy drug, you should talk to your doctor about all your health conditions and any drugs you take, including prescription and over-the-counter drugs, vitamins, and supplements.

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