Allergies
Basics
Allergies are a short-term inflammation of the mucous membranes that line the nasal passages. "Hay fever," as the condition is commonly called, is caused by airborne pollens from trees, grasses, flowers, and weeds. Allergy season typically kicks off in the spring and fall when certain trees or grasses pollinate. When pollen season starts and how long it lasts varies throughout the country. In southern states, trees can start pollinating as early as late February and grass can start by the end of April, while in midwestern states allergies may not flare up until May. Another round of allergies may begin in late summer or early fall when ragweed is the culprit. In western states, grass pollinates for a longer period of time and certain weeds exist that can keep allergies blooming into the fall.
Allergies caused by pollen and other allergens affect 40 million Americans and cost more than $1 billion in annual treatment costs. Although it's usually not a dangerous condition, it can be very uncomfortable and, for some people, can severely disrupt daily activities. The standard reactions include sneezing, itchy throat, headache, swollen sinuses, runny nose, and itchy, watery eyes, .
Causes
In allergies, airborne pollen from various seasonal plants—or, in some cases, spores from mold—enter the body through the eyes, nose, or throat, and trigger an allergic reaction. Normally, the immune system does not respond to mild substances like pollen and mold. But in sensitive individuals, the body's defense mechanism views these allergens as it would an infectious agent and mounts an attack. Once the immune system has detected the "invader," it unleashes a cascade of chemicals such as histamine and other compounds resulting in localized inflammation that leads to irritation and discomfort. The symptoms of allergic reaction begin 5 to 10 minutes after allergen exposure, subside within an hour, and may return two to four hours later.
Symptoms
Allergies produce an array of symptoms, including eye irritation, sneezing, and congestion. Hay fever is not caused by hay, nor does it result in fever.
Common Symptoms of Allergies
Itchy, watery eyes are often the first sign pollen season is underway. Or there may be an initial tickle on the roof of the mouth or in the back of the throat. Sneezing and a runny nose soon follow. Some allergy sufferers experience congestion, headaches, wheezing, and coughing. Symptoms may interfere with sleep and result in irritability. Allergic conjunctivitis, a condition in which the inner eyelids and whites of eyes become inflamed, may occur as well.
Risk Factors
Although allergies can develop later in life, they usually show up before age 20. The average age that allergies begin is 10 years. Sometimes, people first get allergies as young adults or, occasionally, in middle age or later years. Like other problems that involve an abnormal immune system response, allergies tend to run in families. More than half of hay fever sufferers have a close relative with a history of allergies. Hay fever does not seem to discriminate between men and women or ethnic background.
Diagnosis
Allergies are a short-term inflammation of the mucous membranes that line the nasal passages. "Hay fever," as the condition is commonly called, is caused by airborne pollens from trees, grasses, flowers, and weeds. Allergy season typically kicks off in the spring and fall when certain trees or grasses pollinate. When pollen season starts and how long it lasts varies throughout the country. In southern states, trees can start pollinating as early as late February and grass can start by the end of April, while in midwestern states allergies may not flare up until May. Another round of allergies may begin in late summer or early fall when ragweed is the culprit. In western states, grass pollinates for a longer period of time and certain weeds exist that can keep allergies blooming into the fall.
Allergies caused by pollen and other allergens affect 40 million Americans and cost more than $1 billion in annual treatment costs. Although it's usually not a dangerous condition, it can be very uncomfortable and, for some people, can severely disrupt daily activities. The standard reactions include sneezing, itchy throat, headache, swollen sinuses, runny nose, and itchy, watery eyes, .
In allergies, airborne pollen from various seasonal plants—or, in some cases, spores from mold—enter the body through the eyes, nose, or throat, and trigger an allergic reaction. Normally, the immune system does not respond to mild substances like pollen and mold. But in sensitive individuals, the body's defense mechanism views these allergens as it would an infectious agent and mounts an attack. Once the immune system has detected the "invader," it unleashes a cascade of chemicals such as histamine and other compounds resulting in localized inflammation that leads to irritation and discomfort. The symptoms of allergic reaction begin 5 to 10 minutes after allergen exposure, subside within an hour, and may return two to four hours later.
Allergies produce an array of symptoms, including eye irritation, sneezing, and congestion. Hay fever is not caused by hay, nor does it result in fever.
Common Symptoms of Allergies
Itchy, watery eyes are often the first sign pollen season is underway. Or there may be an initial tickle on the roof of the mouth or in the back of the throat. Sneezing and a runny nose soon follow. Some allergy sufferers experience congestion, headaches, wheezing, and coughing. Symptoms may interfere with sleep and result in irritability. Allergic conjunctivitis, a condition in which the inner eyelids and whites of eyes become inflamed, may occur as well.
Although allergies can develop later in life, they usually show up before age 20. The average age that allergies begin is 10 years. Sometimes, people first get allergies as young adults or, occasionally, in middle age or later years. Like other problems that involve an abnormal immune system response, allergies tend to run in families. More than half of hay fever sufferers have a close relative with a history of allergies. Hay fever does not seem to discriminate between men and women or ethnic background.
To determine what is causing your symptoms, your doctor will start with a medical history. Allergic symptoms that show up during pollen season are the biggest indication that you are suffering from allergies. In other words, if April showers bring May flowers plus sneezes and a runny nose, allergies are probably to blame.
Allergies can be triggered by many things, including exposure to house dust and animal dander. Your doctor will want to know if you have pets, if anyone in the house smokes, or if you are taking any medications in order to decipher the cause of your symptoms. Your doctor also will want to know how old you were when you started getting allergy symptoms and if anyone in your family suffers from allergies.
A physical examination can help your doctor rule out mechanical or physical abnormalities that may be causing your symptoms. Your doctor may use a strong light and a nasal speculum to examine your nasal passages for evidence of mechanical obstruction. Clear nasal discharge and a characteristic appearance of the back of the throught suggest that allergic rhinitis is causing your upper respiratory symptoms. Polyps, tumors, and a deviated or perforated septum can cause symptoms that mimic allergies.
Allergy skin tests can help determine which allergens are responsible for your symptoms. For an allergy skin test, your doctor will prick or scratch your skin with a series of needles that contain a minuscule amount of allergens. If one of these areas becomes red or itchy or a raised welt appears, that allergen is the offender. Sometimes your doctor will order a blood test to see if you have a high number of eosinophils, the type of white blood cell that responds to allergies.
When pollen counts are high, seek refuge in a climate-controlled environment if possible. The pollen count peaks between 5 a.m. and 10 a.m. each day. Try to stay indoors during those hours. If you are commuting to work when pollen is at its worst, keep your car windows rolled up and use the air-conditioning. If you think it is too cool for air conditioning, remember that you can adjust the temperature on your dashboard. The air can be "conditioned" and be warm at the same time. Wearing sunglasses may also help to keep pollen out of your eyes. Listen to the radio or watch television news to find out the day's pollen count. If it is high, delay outdoor activities or at least bring allergy medications with you. Some people get monthly allergy shots. You can ask your doctor if those would help lessen your symptoms.
Prevention and Screening
When pollen counts are high, seek refuge in a climate-controlled environment if possible. The pollen count peaks between 5 a.m. and 10 a.m. each day. Try to stay indoors during those hours. If you are commuting to work when pollen is at its worst, keep your car windows rolled up and use the air-conditioning. If you think it is too cool for air conditioning, remember that you can adjust the temperature on your dashboard. The air can be "conditioned" and be warm at the same time. Wearing sunglasses may also help to keep pollen out of your eyes. Listen to the radio or watch television news to find out the day's pollen count. If it is high, delay outdoor activities or at least bring allergy medications with you. Some people get monthly allergy shots. You can ask your doctor if those would help lessen your symptoms.
Treatment
Allergies themselves are not serious. However, infections—such as a sinus infection characterized by fever, pain, and green or yellow nasal discharge—can mimic allergies.
Over-the-counter (OTC) allergy medications may ease your discomfort. Antihistamines can stop the itching and sneezing caused by the release of histamine that the body produces in response to allergens. Antihistamines block the action of histamine. There are many over-the-counter varieties, including diphenhydramine (Benadryl) and clemastine (Tavist).
Although OTC antihistamines are effective in minimizing hay fever symptoms, they can cause extreme drowsiness. In fact, some people use antihistamines as a sleeping aid. Dry mouth is another common side effect. Less common are confusion and blurred vision. Over-the-counter antihistamines all have warning labels urging users not to operate heavy machinery or drive while taking the medication. Pilots are prohibited from using an OTC antihistamine. Some people are able to will themselves to stay awake and remain semi-functional, but do not be fooled by a false sense of well-being. Even if you think you are alert, your coordination and reaction skills are still impaired while on OTC allergy medication.
A nasal decongestant such as pseudoephedrine may help relieve a stuffy nose due to allergies.
This medication constricts the blood vessels and reduces blood flow to the nasal passages, which reduces swelling. Insomnia, restlessness, and difficulty urinating are among the possible side effects. For some people, however, a simple nasal decongestant is not effective because it will not stop sneezing and a runny nose. The pollen will relentlessly trigger the release of histamines, and a nasal decongestant, depending on the severity of the allergies, may not be able to combat the force of the body's reaction.
A commonly used nasal decongestant, phenylpropanolamine (PPA), was pulled off the shelves after the FDA issued a warning on its possible side effects.
Research has linked PPA (a common ingredient in both cold medicines and appetite suppressants) to a slight increase in stroke risk in women. Occasional reports of hemorrhagic stroke (a type of stroke that causes bleeding in the brain) in people using PPA-containing products prompted a careful look at the drug. The studies found that people taking PPA were more likely to have strokes than those not taking PPA. Although the risk of stroke was very low, the FDA recommends that you not use any products that contain PPA because of the seriousness of a stroke and the inability to predict who will be affected. The risk was found primarily in women, though the FDA notes that men may be affected as well.
Your doctor is the best source of information on the drug treatment choices available to you.
Consider allergy shots if you suffer from allergies for many months of the year, cannot tolerate allergy medications, or develop asthma during pollen season. A series of injections can make you less sensitive to the effects of pollen by helping your immune system become increasingly resistant to it. "Immunotherapy" involves injecting small amounts of the specific allergen you are allergic to and gradually increasing the dose so that you develop a tolerance to it. To be effective, injections must be given a regular basis (determined by your allergist) over the course of three to five years.
Some alternative remedies may be helpful in minimizing allergy symptoms. However none of these remedies have been shown to be effective in carefully controlled studies. The herb ephedra (ma-huang) contains ephedrine, a naturally occurring compound that has been employed by pharmaceutical companies in numerous allergy medications. The FDA has banned sales of the herb because it can be dangerous and has been associated with heart attacks and strokes. Do not take ephedra with allergy medications that contain ephedrine as doubling the dose may cause dangerous side effects.
Nettle is a folk remedy for the sneezing, itching, and swelling associated with allergies. The plant contains quercetin, a substance that has been shown to inhibit the release of histamine. In one study of allergy sufferers, more than half of those who took nettle reported that the herb was at least moderately effective in reducing allergy symptoms compared with a placebo. Nettle is considered to be very safe.
Pregnant and breastfeeding women should speak with their doctors before using allergy medications. Some drugs are not safe to use during pregnancy; others can be passed through breast milk and should be avoided by nursing mothers. Dosages are different for adults than they are for children. Follow your doctor's instructions.
Do not use an antihistamine that causes drowsiness before doing activities that require alertness, such as driving, operating machinery, or piloting a plane. OTC and older prescription antihistamines can delay reaction time and interfere with concentration.
Allergies may be controlled with OTC medications. Should these fail to bring you relief, see your doctor about switching medications or beginning allergen immunotherapy.