Allergic rhinitis (hay fever) is an especially common chronic nasal problem in adolescents and young adults. Allergies to inhalants like pollen, dust, and animal dander begin to cause sinus and nasal symptoms in early childhood. Infants and young children are especially susceptible to allergic sensitivity to foods and indoor allergens.
Allergic rhinitis typically results from two conditions: family history/genetic predisposition to allergic disease and exposure to allergens. Allergens are substances that produce an allergic response.Children are not born with allergies but develop symptoms upon repeated exposure to environmental allergens. The earliest exposure is through food—and infants may develop eczema, nasal congestion, nasal discharge, and wheezing caused by one or more allergens (milk protein is the most common). Allergies can also contribute to repeated ear infections in children. In early childhood, indoor exposure to dust mites, animal dander, and mold spores may cause an allergic reaction, often lasting throughout the year. Outdoor allergens including pollen from trees, grasses, and weeds primarily cause seasonal symptoms.
The number of patients with allergic rhinitis has increased in the past decade, especially in urban areas. Before adolescence, twice as many boys as girls are affected; however, after adolescence, females are slightly more affected than males. Researchers have found that children born to a large family with several older siblings and day care attendance seem to have less likelihood of developing allergic disease later in life.
Symptoms can vary with the season and type of allergen and include sneezing, runny nose, nasal congestion, and itchy eyes and nose. A year-long exposure usually produces nasal congestion (chronic stuffy nose).
In children, allergen exposure and subsequent inflammation in the upper respiratory system cause nasal obstruction. This obstruction becomes worse with the gradual enlargement of the adenoid tissue and the tonsils inherent with age. Consequently, the young patient may have mouth-breathing, snoring, and sleep-disordered breathing such as obstructive sleep apnea. Sleep problems such as insomnia, bed-wetting, and sleepwalking may accompany these symptoms along with behavioral changes including short attention span, irritability, poor school performance, and excessive daytime sleepiness.
In these patients, upper respiratory infections such as colds and ear infections are more frequent and last longer. A child’s symptoms after exposure to pollutants such as tobacco smoke are usually amplified in the presence of ongoing allergic inflammation.
Recent studies by otolaryngologist–head and neck surgeons have better defined the association between rhinitis and sinusitis. They have concluded that sinusitis is often preceded by rhinitis and rarely occurs without concurrent rhinitis. The symptoms, nasal obstruction/discharge and loss of smell, occur in both disorders. Most importantly, computed tomography (CT scan) findings have established that the mucosal linings of the nose and sinuses are simultaneously involved in the common cold (previously, thought to affect only the nasal passages). Otolaryngologists, acknowledging the inter-relationship between the nasal and sinus passages, now refer to sinusitis as rhino-sinusitis.
The catalyst relating the two disorders is thought to involve nasal sinus overflow obstruction, followed by bacterial colonization and infection leading to acute, recurrent, or chronic sinusitis. Likewise, chronic inflammation due to allergies can lead to obstruction and subsequent sinusitis.
People who have allergies are often quick to seek help for symptoms like sneezing, sniffling, and nasal congestion. But allergies can affect the eyes as well as the nose, causing red, itchy, burning, and watery eyes and swollen eyelids. The good news is that the same treatments and self-help strategies that ease nasal allergy symptoms work against eye allergies, too.
Like all allergies, eye allergies are caused by a glitch in the body’s immune system. The trouble starts when the conjunctiva (the mucous membrane that lines the eyelids and covers the whites of the eyes) comes into contact with something that, while actually harmless, is seen as a threat. In a mistaken attempt to fight off the threat, the immune system makes antibodies that cause your eyes to release histamine and other substances. That, in turn, makes eyes red, itchy, and watery. Eye allergy symptoms can happen alone or along with nasal allergy symptoms.
Work related sneezing, nasal discharge and obstruction should alert one to possible occupational disease. The onset of symptoms may be similar to occupational lung disease occurring after prolonged and repeated exposure to the offending allergen. Quite often Occupational Rhinitis may precede occupational asthma, thus early diagnosis of occupational rhinitis may enable the employee to avoid further exposure and prevent the development of asthma. Non-allergic Irritant Occupational Rhinitis may occur after exposure to coal dust, talc, chlorine and cold air.
All of us eat to survive, and most of us enjoy eating. However, recent studies have found that almost 1 in 20 young children under the age of 5 years and almost 1 in 25 adults are allergic to at least one food. Other studies indicate that food allergy, especially allergy to peanut, is on the rise. As a result, more and more people are becoming aware of food allergy, making it a subject of increasing public concern.
When one person in a family has a food allergy, the whole family is affected. There may be day-to-day anxiety that a loved one may accidentally eat a food that could lead to anaphylaxis, a dangerous allergic reaction.
This information will help you understand allergic reactions to foods and their possible causes, and it explains how a healthcare professional diagnoses and treats food allergy.
If you suspect you or a member of your family have a food allergy, consult your healthcare professional for medical advice.
Food allergy is an abnormal response to a food triggered by the body’s immune system. There are several types of immune responses to food. This information focuses on one type of adverse reaction to food—that in which the body produces a specific type of antibody called immunoglobulin E (IgE).
The binding of IgE to specific molecules present in a food triggers the immune response. The response may be mild or in rare cases it can be associated with the severe and life-threatening reaction called anaphylaxis, which is described later in this section. Therefore, if you have a food allergy, it is extremely important for you to work with your healthcare professional to learn what foods cause your allergic reaction.
Sometimes, a reaction to food is not an allergy at all but another type of reaction called food intolerance. A description of food intolerance appears later in this booklet.
A food allergy occurs when the immune system responds to a harmless food as if it were a threat. The first time a person with food allergy is exposed to the food, no symptoms occur; but the first exposure primes the body to respond the next time. When the person eats the food again, an allergic response can occur.
An allergic reaction to food is a two-step process.
Step 1:
The first time you are exposed to a food allergen, your immune system reacts as if the food were harmful and makes specific IgE antibodies to that allergen. The antibodies circulate through your blood and attach to mast cells and basophils. Mast cells are found in all body tissues, especially in areas of your body that are typical sites of allergic reactions. Those sites include your nose, throat, lungs, skin, and gastrointestinal (GI) tract. Basophils are found in your blood and also in tissues that have become inflamed due to an allergic reaction.
Step 2:
The next time you are exposed to the same food allergen, it binds to the IgE antibodies that are attached to the mast cells and basophils. The binding signals the cells to release massive amounts of chemicals such as histamine. Depending on the tissue in which they are released, these chemicals will cause you to have various symptoms of food allergy. The symptoms can range from mild to severe. A severe allergic reaction can include a potentially life-threatening reaction called anaphylaxis.
Generally, you are at greater risk for developing a food allergy if you come from a family in which allergies are common. These allergies are not necessarily food allergies but perhaps other allergic diseases, such as asthma or eczema (atopic dermatitis). If you have two parents who have allergies, you are more likely to develop food allergy than someone with one parent who has allergies.
An allergic reaction to food usually takes place within a few minutes to several hours after exposure to the allergen. The process of eating and digesting food and the location of mast cells both affect the timing and location of the reaction.
If you are allergic to a particular food, you may experience all or some of the following symptoms:
Eosinophilic esophagitis (EoE) is a newly recognized chronic disease that can be associated with food allergies. It is increasingly being diagnosed in children and adults.
Symptoms of EoE include nausea, vomiting, and abdominal pain after eating. A person may also have symptoms that resemble acid reflux from the stomach. In older children and adults, it can cause more severe symptoms, such as difficulty swallowing solid food or solid food sticking in the esophagus for more than a few minutes. In infants, this disease may be associated with failure to thrive.
If you are diagnosed with EoE, you will probably be tested for allergies. In some situations, avoiding certain food allergens will be an effective treatment for EoE.
If you have a life-threatening reaction to a certain food, your healthcare professional will show you how to avoid similar foods that may trigger this reaction. For example, if you have a history of allergy to shrimp, allergy testing will usually show that you are also allergic to other shellfish, such as crab, lobster, and crayfish. This is called cross-reactivity.
If you have a food allergy, there is a chance that you may experience a severe form of allergic reaction known as anaphylaxis. Anaphylaxis may begin suddenly and may lead to death if not immediately treated. Anaphylaxis includes a wide range of symptoms that can occur in many combinations. Some symptoms are not life-threatening, but the most severe restrict breathing and blood circulation.
Many different parts of your body can be affected.
Symptoms may begin within several minutes to several hours after exposure to the food. Sometimes the symptoms go away, only to return 2 to 4 hours later or even as many as 8 hours later. When you begin to experience symptoms, you must seek immediate medical attention because anaphylaxis can be life-threatening.
Anaphylaxis caused by an allergic reaction to a certain food is highly unpredictable. The severity of a given attack does not predict the severity of subsequent attacks. The response will vary depending on several factors, such as
Any anaphylactic reaction may become dangerous and must be evaluated by a healthcare professional.
Food allergy is the leading cause of anaphylaxis. However, medications, insect stings, and latex can also cause an allergic reaction that leads to anaphylaxis.
In infants and children, the most common foods that cause allergic reactions are
In adults, the most common foods that cause allergic reactions are
Food allergies generally develop early in life but can develop at any age. For example, milk allergy tends to develop early in life, whereas shrimp allergy generally develops later in life.
Children usually outgrow their egg, milk, and soy allergies, but people who develop allergies as adults usually have their allergies for life. Children generally do not outgrow their allergy to peanut.
Finally, foods that are eaten routinely increase the likelihood that a person will develop allergies to that food. In Japan, for example, rice allergy is more frequent than in the United States, and in Scandinavia, codfish allergy is more common than in the United States.
Food allergy is sometimes confused with food intolerance. To find out the difference between food allergy and food intolerance, your healthcare professional will go through a list of possible causes for your symptoms.
Lactose is a sugar found in milk and most milk products. Lactase is an enzyme in the lining of the gut that breaks down or digests lactose. Lactose intolerance occurs when lactase is missing. Instead of the enzyme breaking down the sugar, bacteria in the gut break it down, which forms gas, which in turn causes symptoms of bloating, abdominal pain, and sometimes diarrhea.
Lactose intolerance is uncommon in babies and young children under the age of 5 years. Because lactase levels decline as people get older, lactose intolerance becomes more common with age. Lactose intolerance also varies widely based on racial and ethnic background.
Your healthcare professional can use laboratory tests to find out whether your body can digest lactose.
Another type of food intolerance is a reaction to certain products that are added to food to enhance taste, add color, or protect against the growth of microbes. Several compounds such as MSG (monosodium glutamate) and sulfites are tied to reactions that can be confused with food allergy.
MSG is a flavor enhancer. When taken in large amounts, it can cause some of the following:
These passing reactions occur rapidly after eating large amounts of food to which MSG has been added.
Sulfites:
Sulfites can cause breathing problems in people with asthma.The Food and Drug Administration (FDA) has banned sulfites as spray-on preservatives for fresh fruits and vegetables. When sulfites are present in foods, they are listed on ingredient labels.
Gluten is a part of wheat, barley, and rye. Gluten intolerance is associated with celiac disease, also called gluten-sensitive enteropathy. This disease develops when the immune system responds abnormally to gluten. This abnormal response does not involve IgE antibody and is not considered a food allergy.
Some of the symptoms of food allergy, such as abdominal cramping, are common to food poisoning. However, food poisoning is caused by microbes, such as bacteria, and bacterial products, such as toxins, that can contaminate meats and dairy products.
Fish, such as tuna and mackerel that are not refrigerated properly and become contaminated by bacteria, may contain very high levels of histamine. A person who eats such fish may show symptoms that are similar to food allergy. However, this reaction is not a true allergic reaction. Instead, the reaction is called histamine toxicity or scombroid food poisoning.
Several other conditions, such as ulcers and cancers of the GI tract, cause some of the same symptoms as food allergy. These symptoms, which include vomiting, diarrhea, and cramping abdominal pain, become worse when you eat.
