Environmental allergies are becoming more prevalent and are not likely to recede any time soon. Treatment options, though, are expanding and improving, giving internists and allergists a wide range of therapy options.
According to the American College of Allergy, Asthma, and Immunology, allergies are the sixth leading cause of chronic illness in the U.S., with an annual cost of around $18 billion. One in 5 Americans have some kind of allergy, many of which are environmental in nature.
The Centers for Disease Control and Prevention estimates that the rate of asthma in the United States grew 28% from 2001 to 2011. Allergy sufferers are more likely to develop asthma, and allergic asthma is the most common form of the condition, accounting for more than half of cases. The most common allergic asthma triggers are environmental and include seasonal pollen, dust mites, pet dander, and cockroaches.
“The prevalence seems to be increasing,” said Rohit K. Katial, MD, FACP, a professor of medicine, co-director of The Cohen Family Asthma Institute, and director of the allergy and clinical immunology fellowship at the National Jewish Health medical center in Denver. “There are all sorts of theories for this.”
Although there is no clear cause, a sprawling blend of societal changes may be driving up pollen counts and human sensitivity.
Perhaps the most prominent theory, allergists said, is the so-called hygiene hypothesis, which posits that over-sanitization reduces everyday bacterial exposures and makes one more likely to develop allergies early in life. Modern home weatherproofing exacerbates the situation by sealing occupants against the outdoors and increasing exposure to indoor allergens.
On the other end of the hypothetical spectrum, pollen may be more widespread because of climate change. Warmer temperatures lead to increased pollen counts and longer allergy seasons.
“No one really knows why this is happening,” said Maria C. Castells, MD, PhD, an allergist/immunologist with Harvard Medical School and Brigham and Women's Hospital in Boston. “We have a cleaner society, and we have more allergies, and that is true for all allergies ... Because of climate change, pollen stays in the air for a longer period of time in the summer and fall. That increases exposure.”
The symptoms most frequently associated with hay fever or allergic rhinitis—sneezing, runny nose, nasal congestion, itchy or watery eyes—are familiar. But they are not the only ones.
According to John Kelso, MD, an allergist/immunologist with the Scripps Clinic in San Diego and a clinical professor of pediatrics and internal medicine at University of California, San Diego, School of Medicine, managing allergies begins with the patient history.
“Ask if [a symptom] appears to be seasonal or if there are any particular triggers,” Dr. Kelso said. “If either of those are true, it's more likely to be allergic rhinitis.”
He also noted that allergic shiners, or dark circles under the eyes, while not always caused by allergies, may be a tipoff, as can itching in the palette or ears.
Some patients with allergies present with rash, pruritus, or wheezing, according to De-Yun Wang, MD, PhD, director of research and a professor in the department of otolaryngology at Yong Loo Lin School of Medicine at the National University of Singapore.
Oral allergy syndrome, characterized by itching or swelling in the mouth or throat after patients eat certain fresh fruits or vegetables, can also be a giveaway. This syndrome represents cross-reactivity of proteins in some raw fruits and vegetables and those of specific pollens. The food-related symptoms can tip physicians off to an associated pollen allergy.
“When people have a reaction when they eat fresh fruits like apples or melons, it's a virtual certainty they'll have allergic rhinitis,” Dr. Kelso said.
Basic best practices
Just as environmental allergies arise from various factors, so, too, is there a wealth of treatment combinations. Some therapeutic options are tried and true. Others are more novel.
The cornerstone of treatment remains the simplest, almost to the point of tautology: Fighting environmental allergies begins with the environment.
“Avoidance of allergen exposure,” Dr. Wang said, “is always the first thing to do.”
Environmental control strategies vary by allergen. A pet dander allergy, for example, means bathing pets regularly, keeping them out of bedrooms, and using filters in vacuum cleaners and heating and air conditioning systems that meet the high-efficiency particulate arrestance (HEPA) standard. Dust mite allergies mean using hot water to wash bedding and allergen-proof cases for pillows and mattresses.
A more fluid part of the treatment equation is the spectrum of available medication.
Over-the-counter corticosteroid nasal sprays and antihistamines remain popular. Nasal corticosteroids help with congestion and inflammation; antihistamines address runny nose, sneezing, and itching.
“A relatively new entry into the field are topical antihistamine nasal sprays,” Dr. Kelso said. “You can take these if you don't get enough relief from the nasal corticosteroid spray alone.”
Some manufacturers combine corticosteroid and antihistamine into 1 nasal spray. This can deliver relief and convenience, but is usually more costly than purchasing each medication separately and combining them at home with a physician's guidance, Dr. Kelso noted.
Because many allergy medications (both over-the-counter and prescription) have the same or similar formulations, Dr. Kelso recommends those that are least expensive, depending on patient insurance status.
“I go with whatever has the least out-of-pocket costs,” he said. “It could be that they have a lower copay for a prescription, and if not, sometimes they can order it through Amazon.”
One of the most effective treatment options is allergen immunotherapy. Almost anyone, including children and adults, is eligible to receive the injections, and efficacy is high. (The American Academy of Allergy, Asthma, and Immunology does not typically recommend allergy shots for children younger than 5, and older adults may require closer oversight because of various potential conditions, including heart disease.)
Another, newer immunotherapy iteration is also emerging. In 2014, the U.S. Food and Drug Administration approved sublingual immunotherapy (SLIT) allergy tablets, which administer allergy medications under the tongue, rather than via injections.
So far, the FDA has approved SLIT treatments for grass and ragweed pollens. The first dose must be taken at a clinician's office, where the patient remains for at least 30 minutes in case of potential adverse reactions. Early studies indicate a reduction in symptoms, although SLIT may not always be as effective as immunotherapy injections. Additional studies are ongoing.
One of the downsides to immunotherapy injections is the time commitment involved. Because of a small but real risk of anaphylactic shock, patients wait 30 minutes in the physician's office after the injection. Patients typically receive 2 injections a week for 3 to 6 months, then monthly maintenance doses for about 5 years.
“Shots are exceedingly effective,” Dr. Kelso said. “For people with typical hay fever, the overwhelming majority have complete or near complete relief with those. People can still continue with [oral] medicines in addition to the shots, but the shots work so well they often don't need to take any more medicine.”
Experts caution, however, that patients should not discontinue the adaptations they've made in their homes or workplaces.
“Without the environmental control measures,” Dr. Kelso said, “the shots can be overwhelmed.”
Primary care vs. allergist?
Internists are well equipped to manage the symptoms of common environmental allergies. But while allergists/immunotherapists are appropriate for special cases or treatments (including immunotherapy injections), they also are receptive to handling milder or more general cases.
“With a careful history and some limited tests, [internists] can make a diagnosis of allergic rhinitis and do environmental controls and medicines that will provide adequate relief,” Dr. Kelso said. “If for some reason it doesn't work, or if the patient or provider prefers or is considering allergy shots, you can make a referral.”
An allergist or specially trained primary care physician must supervise allergen immunotherapy. Outside of that, there are no hard-and-fast rules for when to refer. To become a full-fledged allergist, physicians complete an accredited 2-year fellowship in addition to training as an internist, pediatrician, or both.
According to a 2011 practice parameter published by the American Academy of Allergy, Asthma, and Immunology, “the physician's office should have the expertise, personnel, and procedures in place for the safe and effective administration of immunotherapy ... A physician or qualified physician extender (nurse practitioner or physician's assistant) should be present and immediately available and be prepared to treat anaphylaxis when immunotherapy injections are administered. Regular practice drills with the office staff for handling systemic reactions to immunotherapy reactions should be considered.”
“It all boils down to quality of life,” Dr. Castells said. “If [a primary care physician] can manage symptoms with a steroid and over-the-counter medication, you may not need an allergist. If a patient is waking up in the middle of the night or can't go to the park and play with their kids or do sports despite medication, they may need to be seen by an allergist.”