Wednesday August 23, 2017

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August 18

Guidelines for the Diagnosis and Management of Food Allergy

The Guidelines for the Diagnosis and Management of Food Allergy in the United States: Report of the NIAID-sponsored Expert Panel is a report developed by a 25-member expert panel to help healthcare professionals, including family practice physicians, medical specialists, and nurses, to better care for their patients with food allergy. The guidelines are based on the most up-to-date scientific and clinical information about food allergy and the consensus expert opinion of the panel members.


August 18

Dr. Bielory - Wall Street Journal - Allergies

Teri Augustyn developed a runny nose and itchy eyes when she went near grasses, trees and even the dog she'd had for years after she moved from Michigan to Washington when she was 38.

[HEALTHCOL]Getty Images

Pollen may irritate respiratory passages more as people age.

At age 25, Kiley Gwynn started having headaches and stomachaches and one day her regular soy chai latte gave her a 20-minute coughing fit. Her allergist traced the reaction to soy, which she'd eaten all of her life without problems.

Lauri Granoff was 53 when she opened a package of wet wipes and suddenly couldn't breathe. The fragrance set off an asthma-like reaction that made her throat close up and her chest tighten. Now, coming close to perfume, hairspray, hand lotion or other chemical fragrance will leave her gasping for breath. She enclosed an insert in her son's wedding invitations begging guests not to wear scented products of any kind.

Severe reactions like these to foods, drugs, pollen and other substances can develop, seemingly out of the blue, at any age.

The symptoms mimic allergy attacks, and the misery they cause can be just as severe.

But many times, they aren't true allergies, experts say. The reactions involve different biochemical pathways than those in allergies, and they often respond to different treatments.

A true allergic reaction occurs when a person's immune system misidentifies a harmless substance as an invader and develops IgE antibodies against it. The antibodies attach themselves to mast cells in the bloodstream, which release histamines and other inflammatory chemicals whenever that substance is near. The resulting inflammation may cause a runny nose, itchy eyes, swelling, hives or skin rashes.

But when seasonal allergy symptoms crop up for the first time in adulthood, they are more likely due to an irritation of the nasal membranes known as vasomotor or nonallergic rhinitis than to an IgE response, experts say.

As people age, their immune systems weaken and their mucous membranes lose elasticity, making them more sensitive to irritants. "Even cold air becomes more problematic as we get older," says Rohit Katial, director of adult allergy and immunology services at National Jewish Health, a Denver hospital. "Suddenly your nose starts running all the time."

Because the IgE reaction isn't involved in vasomotor rhinitis, antihistamines and other over-the-counter allergy medications aren't very effective, nor are allergy shots. But nasal steroid sprays such as Flonase and Nasonex can reduce the inflammation and make nasal passages less sensitive. "Half the people who come to me who think they have allergies don't, and they're frustrated because their over-the-counter allergy medications don't work," says Michael Blaiss, an allergist at the University of Tennessee in Memphis and past president of the American College of Allergy, Asthma and Immunology.

Reactions to perfume and other scents also are more likely to be irritations than allergies and can range from headaches to life-threatening asthma-like attacks. Cigarette smoke, soot and other airborne particles also can be irritating to people who are sensitive, and there, too, antihistamines generally aren't effective.

Many sufferers, though, find relief using inhalers with fast-acting anticholinergic agents, which block the nerve impulses that play a role in the reactions. Ms. Granoff also uses a carbon-filter mask to screen out scents and particulates and carries a portable nebulizer and an epinephrine pen for emergencies. Many patients at National Jewish Health learn breathing exercises to help keep their airways open during an attack.

About 1% of people—and 10% of those with asthma—develop a sudden sensitivity to aspirin, ibuprofen and other nonsteroidal anti-inflammatory drugs (NSAIDs). Experts say these reactions—which may include swelling of the lips, tongue, hands and feet, as well as hives and other rashes—may happen because the NSAID doesn't fully block the body's inflammation-causing chemicals, and some overproduce instead. Researchers aren't sure why this suddenly occurs in people who have taken NSAIDs without problems for years, although stress and genetics may play roles.

Some food allergies actually do develop mainly in adults. A prime example is shellfish. But in many other cases, reactions that are widely assumed to be food allergies prove negative in medically supervised food challenges.

Often, it is simply mistaken identity. "Somebody might develop hives one afternoon, and it's natural to think, 'It must have been the eggs I had at lunch'," says Dr. Katial. "A lot of times we don't know what the cause is, but we know it's not the food allergy."

Skin-prick and blood tests can help confirm or rule out allergies by revealing the presence of IgE antibodies to specific substances. But a positive skin test alone doesn't necessarily mean a person will have a bad reaction from eating the food. That's why experts say children and adults shouldn't eliminate foods from their diets based on suspicion or a positive skin test alone.

The incidence of actual allergies is rising in adults and children around the world, for reasons that aren't totally understood. A popular theory is that modern hygiene has reduced the number of germs children are exposed to, so that their immune systems don't develop fully and attack harmless substances. Allergies may develop late in life, or seem to do so, in adults who had mild seasonal allergies that went unnoticed when they were children; the allergies may have become more severe as pollen counts have worsened.

Some environmental triggers are getting worse. In northern U. S. and Canada, pollen season in 2009 lasted 27 days longer than in 1995, a recent study found. Ragweed season in the New York-New Jersey area started last week, 10 days earlier than usual, says Leonard Bielory, an allergy specialist at Rutgers University and co-author of the study in the Proceedings of the National Academy of Science. "My prediction is that next week, it will just explode."

A new environmental irritant, a previously mild allergy and the aging process can add up to new misery. Pregnancy, hormonal changes and many illnesses can alter a person's immune system. "As we get older, things change," Dr. Bielory says.

Does it matter which mechanism creates a bad reaction? Not to suffering patients—although some worry that an "irritation" isn't taken as seriously as an "allergy." But a true diagnosis is critical to getting the right treatment. "I tell primary-care doctors that if you think the patient has allergies and they get better on over-the-counter antihistamines, I don't need to see them," says Dr. Blaiss. "But if they are still having problems or getting worse, we should investigate further."

 
Allergies and Beyond

Are a runny nose, itchy eyes, swelling or hives signs of an adult-onset allergy—or something else?

Vasomotor rhinitis

Pollen, dander, smoke, perfume—even cold air—can irritate respiratory passages; aging makes people more susceptible

Treatment: Allergy shots and antihistamines don't help, but nasal steroid sprays, anticholinergic inhalers, masks and breathing exercises may provide relief.

Severity: Mild sniffles to life-threatening airway blockage

Prevalence: 20% of U.S. adults report seasonal symptoms, 4% fragrance sensitivity

Aspirin sensitivity

[HEALTHCOLjp2]Getty Images

Aspirin

Nonsteroidal anti-inflammatory drugs like aspirin and ibuprofen can trigger swelling, hives and breathing problems

Treatment: IV antihistamines; epinephrine; avoidance; desensitization

Severity: Mild swelling to life-threatening anaphylaxis

Prevalence: 1% of population; 10% of asthmatics

Seasonal allergies

Getty Images
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HEALTHCOLjp3

Rising pollen counts, ozone and other pollutants are making some mild allergies far more severe

Treatment: Antihistamines; nasal sprays, steroids, allergy shots

Severity: Mild sneezing to congestion that interferes with work, sleep, daily life

Prevalence: 20% to 40% of U.S. adults report some form 
of allergy

Source: WSJ reporting

http://online.wsj.com/article/SB10001424053111903480904576510302458640840.html?mod=WSJ_hpp_MIDDLE_Video_Top#articleTabs%3Darticle

August 17

Omega and Dry Eye Syndrome

Omega-3 acids may help alleviate some of your dry-eye patients’ symptoms. 
Still, the quantity of omega-3 acids that patients need for lasting benefits are under investigation. Omega-3 acids are found in walnuts and oily, cold, dark fish such as tuna and salmon. Omega-6 acids are found in meat, canola and corn oil, and margarine. Although both kinds of fats are needed to function, omega-3 acids are healthier than the omega-6 acids. Although humans evolved on a diet with an omega-6 to omega-3 acid of one, omega-6 consumption in the typical Western diet can outweigh omega-3 acids by 16 times, according to a study from the October 2002 issue of Biomedicine and Pharmacotherapy. Omega-3 acids may benefit dry eye by reducing inflammatory activity in the body and by possibly altering the lipid profiles of the meibomian glands. Some components of the omega-3 acids are thought to stimulate aqueous tear secretion.


August 16

Food Allergy

Introduction to food allergies

 

Either food allergy or food intolerance affects nearly everyone at some point. When people have an unpleasant reaction to something they ate, they often think that they have an allergy to the food. Actually, however, only about 1% of adults and 3% of children have clinically proven true allergic reactions to food.

This difference between the prevalence of clinically proven food allergy and the public's perception of the problem is due primarily to misinterpreting food intolerance or other adverse reactions to food as food allergy. Food allergy is an abnormal response to food that is triggered by a specific reaction in the immune system and expressed by certain, often characteristic, symptoms. Other kinds of reactions to foods that are not food allergies include food intolerances (such as lactose or milk intolerance), food poisoning, and toxic reactions. Food intolerance also is an abnormal response to food, and its symptoms can resemble those of food allergy. Food intolerance, however, is far more prevalent, occurs in a variety of diseases, and is triggered by several different mechanisms that are distinct from the immunological reaction responsible for food allergy.

People who have food allergies must identify and prevent them because, although usually mild and not severe, these reactions can cause devastating illness and, in rare instances, can be fatal.

 

How do allergic reactions to food occur?

 

The allergens in food are those components that are responsible for inciting an allergic reaction. They are proteins that usually resist the heat of cooking, the acid in the stomach, and the intestinal digestive enzymes. As a result, the allergens survive to cross the gastrointestinal lining, enter the bloodstream, and go to target organs, causing allergic reactions throughout the body. The mechanism of food allergy involves the immune system and heredity.

Immune system: An allergic reaction to food involves two components of the immune system. One component is a type of protein, an antibody called immunoglobulin E (IgE), which circulates through the blood. The other is the mast cell, a specialized cell that is found in all tissues of the body. The mast cell is especially common, however, in areas of the body that are typical sites of allergic reactions, including the nose and throat, lungs, skin, and gastrointestinal tract.

Heredity: The tendency of an individual to produce IgE against something seemingly as innocuous as food appears to be inherited. Generally, people with allergies come from families in which allergies are common -- not necessarily to food but perhaps allergies to pollen, fur, feathers, or drugs. Thus, a person with two allergic parents is more likely to develop food allergies than someone with one allergic parent.

Mechanism: Food allergy is a hypersensitivity reaction, meaning that before an allergic reaction to an allergen in food can occur, a person needs to have been exposed previously, that is, sensitized, to the food. At the initial exposure, the allergen stimulates lymphocytes (specialized white blood cells) to produce the IgE antibody that is specific for the allergen. This IgE then is released and attaches to the surface of the mast cells in different tissues of the body. The next time the person eats that food, its allergen hones in on the specific IgE antibody on the surface of the mast cells and prompts the cells to release chemicals such as histamine. Depending upon the tissue in which they are released, these chemicals cause the various symptoms of food allergy.


What are the symptoms and signs of food allergy?


The complex process of digestion affects the timing, location, and particular symptoms of an allergic reaction to food. All of the symptoms of food allergy occur within a few minutes to an hour of eating. A food allergy can initially be experienced as an itching in the mouth and difficulty swallowing and breathing. Then, during digestion of the food in the stomach and intestines, symptoms such as nausea, vomitingdiarrhea, and abdominal pain can start. Incidentally, the gastrointestinal symptoms of food allergy are those that are most often confused with the symptoms of different types of food intolerance.

As mentioned previously, the allergens are absorbed and enter the bloodstream. When they reach the skin, allergens can induce hives or eczema, and when they reach the airways, they can cause asthma. As the allergens travel through the blood vessels, they can cause lightheadedness, weakness, and anaphylaxis, which is a sudden drop in blood pressure. Anaphylactic reactions are severe even when they start off with mild symptoms, such as a tingling in the mouth and throat or discomfort in the abdomen. They can be fatal if not treated quickly.


August 16

Air Cleaners and Secondhand Smoke

...Secondhand smoke exposure is a daily health risk encountered by too many children in the United States, with more than 30% of all children exposed to secondhand smoke in their homes. The prevalence of this problem increases to 40% or more among children living in poverty. Smoking increases airborne levels of particulate matter (PM) by 25 to 45 µg/m3 vs increases of only 3 to 6 µg/m3with activities such as indoor sweeping or cooking. It is this nonnicotine PM that particularly increases the risk for asthma symptoms among children with asthma. Although air cleaners provided reductions in mean fine and coarse PM (PM2.5 and PM2.5-10) concentrations in both air cleaner groups vs the control group (PM2.5 concentrations, P = .003; and PM2.5-10concentrations, P = .02 for differences between both air cleaner groups and control). However, the presence of secondhand smoke, as measured by air nicotine and urine cotinine concentrations, was equal between those groups that had air cleaners and those that did not.

Arch Pediatr Adolesc Med. 2011;165:741-748.


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Location: Springfield, NJ
Today's Date: August 23, 2017
Station Director: Leonard Bielory, M.D
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