Pollen Allergies

Pollen allergies are some of the most common chronic diseases in the United States, affecting an estimated 35 million people, according to the National Institute of Allergy and Infectious Diseases (NIAID). And of all the things that cause an allergy, pollen is one of the most widespread.

When someone has an allergy, they're sensitive to substances that don't affect most people, in this case, pollen. (Read about "Allergies") The most telling sign of pollen allergy is that it is seasonal; people only have symptoms when the pollen they are allergic to is in the air. This type of allergy is termed "seasonal allergic rhinitis." Rhinitis is the term for an inflammation in the nose. When a person is allergic to several pollens and/or molds or dust (Read about "Mold Allergies" "Dust Allergies"), and thus has symptoms year round, it's called "perennial allergic rhinitis." (Read about "Sinusitis & Rhinitis")

Symptoms of pollen allergies often involve the respiratory tract. (Read about "Respiratory System") The eyes and skin can be affected too. (Read about "The Eye" "Skin") Symptoms can include:

• sneezing
• runny and/or stuffy nose
• watery eyes
• coughing
• itchy eyes, nose or throat
• dark circles under the eyes
• hives (Read about "Hives")
• conjunctivitis/pink eye (Read about "Conjunctivitis")

An allergic reaction to pollen involves two features of the human immune response. (Read about "The Immune System") One is the production of immunoglobulin E (IgE), a type of protein called an antibody that circulates through the blood. The other is the mast cell, a specific cell that occurs in all body tissues but is especially common in areas of the body that are typical sites of allergic reactions, including the nose and throat. In someone with a pollen allergy, pollen causes certain cells to produce specific IgE in large amounts. The IgE is then released and attaches to the surface of mast cells. The next time the person comes in contact with that trigger, it interacts with specific IgE on the surface of the mast cells and tells the cells to release chemicals such as histamine. When this happens in the nose or throat, classic allergy symptoms result.

If your symptoms are caused by pollen, they will tend to recur at the same time each year. That's because most plants have generally the same pollinating season each year. Trees often pollinate in the spring, grasses in the summer and many weeds in the fall. We often talk about "hay fever" or "rose fever," but NIAID says it isn't hay or roses that cause the problem. The pollen that causes most pollen allergies tend to come from plain-looking plants (trees, grasses and weeds) rather than those with showy flowers. Ragweed, for example, is a common cause of pollen allergy. Depending on what you are allergic to and where you live, you can usually count on your symptoms starting around the same time each year.

The Food and Drug Administration (FDA) says generally, people with pollen allergies come from families in which allergies are common. Those allergies can be to just about anything, not only pollen, including food, animal dander, mold, dust or other substances that can cause reactions. (Read about "Food Allergies" "Animal Dander" "Mold Allergies" "Dust Allergies") Someone with two allergic parents is more likely to develop allergies than someone with one allergic parent.

Though pollen is one of the most widespread allergens, there are things you can do to avoid it. It can be helpful to pay attention to pollen counts given in local weather reports. A pollen count is a measure of how much pollen is in the air at a given time. Counts tend to be higher in the morning and on dry, windy days. It's a good idea to stay indoors when pollen counts are high.

Some other tips include:

• showering after being outside
• keeping doors and windows closed
• wearing a mask when working outdoors
• using the air conditioner in your home and car
• taking a vacation during the height of your allergy season

A more extreme solution could be to move to an area where the allergen doesn't grow. However, people who are sensitive to one substance can often develop allergies to another. So, it's possible you could become allergic to something in your new neighborhood. You may want to consult your doctor or allergist before planning such a drastic move.

The next step in allergy control is medications. (Read about "Medicine Safety") There are several types:

• Antihistamines counter the effects of histamine, which is released by the mast cells in the body's tissues and contributes to allergy symptoms. Because of how they work, antihistamines help to relieve the sneezing and itching symptoms. Many antihistamines can produce drowsiness. There are also less sedating antihistamines, but NIAID says some of these can have serious side effects, particularly if they are taken with certain other drugs, so always discuss this with your doctor. Antihistamines come in pill, liquid and other forms.
• Topical nasal steroids are anti-inflammatory drugs that stop the allergic reaction. They can reduce the number of mast cells in the nose and reduce mucus secretion and nasal swelling. Ask your doctor about side effects.
• Corticosteroid eye drops can help to relive itchy and watery eyes. They should not be used if you have certain eye conditions such as glaucoma, so talk with your doctor. (Read about "Glaucoma") There are also antihistamine eye drops.
• Nasal decongestants may be used also, though not for more than a few days, since longer use can lead to even more congestion and swelling of the nasal passages. Again, talk this over with your doctor. Oral decongestants may raise blood pressure. (Read about "Hypertension: High Blood Pressure") Check with your doctor if you are taking heart medication.
• Leukotriene modifiers block the effects of certain inflammatory chemicals released by your immune system during an allergic reaction.
• Mast cell stabilizers prevent the release of histamine. They come in different forms.

In some cases, immunotherapy or allergy shots may be needed. In immunotherapy, extracts of the offending allergen are injected in the individual in gradually increasing doses. This can help the patient build up immunity to the allergen. The decision to use immunotherapy is based on a number of factors, including how long you've had the allergy and how well you can control it with medication and/or avoidance. Immunotherapy can require a long-term commitment, and costs depend on factors such as where you live and what type of insurance you have. As always, the way someone will react to treatment can vary, so make sure to discuss all options with your physician.

Related Information:

    Immune System Glossary