![]() Allergen-Mediated DiseaseKeeping Patients ActiveJohn W. O'Kane, MD; Ginger A. Woodford, PharmD THE PHYSICIAN AND SPORTSMEDICINE - VOL 27 - NO. 9 - SEPTEMBER 1999
Correction: In "Allergen-Mediated Disease: Keeping Patients Active" (September, page 49), two dosages were listed incorrectly and two drugs were mislabeled as sedating in table 1 (page 54) because of errors introduced in editing. The correct dosage for cetirizine hydrochloride is 5 or 10 mg orally once a day. The correct dosage for budesonide is 2 sprays twice a day or 4 sprays once a day. In addition, cetirizine and fexofenadine hydrochloride should be listed as causing little or no sedation. The corrected version of this table is available on this page.
In Brief: A nasal corticosteroid is the most effective treatment for allergic rhinitis, but delayed improvement can reduce compliance. Topical vasoconstrictors, cromolyn, and NSAIDs are recommended for allergic conjunctivitis. Some athletes who have exercise-induced or exercise-exacerbated asthma may have a refractory period, which, along with short- and long-term beta-2 agonists, inhaled corticosteroids, and leukotriene antagonists, may be used to manage symptoms. Topical steroids are the main treatment for atopic dermatitis. Drug restrictions by sports governing bodies can limit therapies for competitive athletes. Allergic disease is common among athletes and the general public, accounting for many healthcare visits annually. Allergic disorders can be particularly debilitating for athletes and exercisers because they may compromise upper airway and pulmonary function, skin integrity, and, consequently, performance. Four common allergen-mediated diseases are allergic rhinitis and conjunctivitis, atopic dermatitis, and asthma. Identifying their triggers and physiologic pathways can help physicians and athletes manage these disorders through nonpharmacologic and pharmacologic therapies. Physiologic MechanismsAllergic rhinitis, conjunctivitis, atopic dermatitis, and asthma can occur alone or together in allergic (atopic) individuals. Not surprisingly, the diseases share common pathophysiologic mechanisms. Typical allergens include plant pollens, animal dander, dust mites, and certain foods. Atopic individuals may or may not have elevated serum immunoglobulin E (IgE) specific for these or other allergens. When allergen exposure occurs, IgE associated with mast cells or basophils binds the allergen, and subsequent cell degranulation releases histamine, leukotrienes, and other inflammatory mediators. This immediate hypersensitivity has effects on target tissue, including increased vascular permeability and capillary leak, vasodilation, bronchoconstriction, and sensory stimulation, resulting in itching and sneezing. In the 4 to 8 hours following allergen exposure, cytokines, acting as chemoattractants, mediate the late-phase response, causing an influx of multiple inflammatory cells, including T-lymphocytes, macrophages, and additional eosinophils and basophils. The T-lymphocytes (TH2) and macrophages are primarily responsible for inflammatory changes resulting in allergen-mediated chronic tissue damage. Eosinophils and basophils are responsible for the priming response that makes the target tissue more susceptible to subsequent episodes of immediate hypersensitivity. An understanding of this pathophysiologic cascade can guide the planning of an optimal treatment regimen. In difficult cases, treatment should target as many steps in the cascade as possible. Measures include allergen avoidance if possible, desensitization to the allergen, and medications that block the immediate hypersensitivity and the chronic inflammatory response. Because of the priming effect, susceptible persons should be pretreated to minimize symptoms. Allergic RhinitisSymptoms and susceptibility. Allergic rhinitis affects 10% to 30% of adults (1). It is caused by allergen-induced inflammation of the nasal mucosa, resulting in rhinorrhea, sneezing, itching, and nasal congestion. Fatigue, headache, and malaise are also common. Allergic conjunctivitis may also accompany rhinitis. Seasonal allergic rhinitis ("hay fever") is caused by pollens or molds, and perennial allergic rhinitis is caused by animals, dust mites, occupational allergens, or molds and pollens that are present year-round. A positive family history of allergies, particularly in both parents, increases the risk of developing allergic rhinitis. The risk increases with age into early adulthood. Athletes in any sport may be affected, depending on the allergens involved. Those with pollen allergies are often most symptomatic during outdoor spring or fall sports. Athletes who play on natural turf may have significant symptoms after the grass has been mowed. College-age athletes attending school away from home may develop seasonal allergic rhinitis because of a new environmental exposure. Perennial allergies to mold or dust mites may also be exacerbated by poorly ventilated or infrequently cleaned dorm rooms. History. To help identify potential allergens, a history should include potential exposures during sports and other activities, exposures to animals, and the timing of symptoms. A family history and a history of favorable response to antihistamines are also important. Concomitant allergic disease such as atopic dermatitis, conjunctivitis, or asthma should also be investigated because successful treatment should address each manifestation of allergen-mediated disease (2). The history should also explore other causes of rhinorrhea and congestion, including viral upper respiratory tract infection (URTI), acute and chronic sinusitis, and the use of oral contraceptives, excessive topical nasal decongestants, and cocaine. Physical exam. The physical examination should include an examination of the nares, which can be aided by a nasal speculum. Pale, edematous, bluish-gray mucosa is common in allergic rhinitis, while erythema is more common in URTI. The turbinates should be inspected, since regional mucopurulent exudate may indicate sinusitis. Polyps and septal deviation, if present, may account for nasal obstruction. An examination of the tympanic membrane may reveal serous otitis media from chronic eustachian-tube dysfunction. Patients should also be evaluated for other manifestations of allergic disease discussed below. Diagnostic tests. Skin-prick testing for common allergens can help identify an offending allergen that patients can attempt to avoid or to which they can be desensitized. If nasal airway obstruction or anatomic variation is thought to be a contributing factor, fiber-optic nasal endoscopy can be useful. Limited computed tomography of the sinuses is a cost-effective, accurate way to evaluate for chronic sinusitis. Minimizing exposure. Avoiding allergens is one means of nonpharmacologic treatment that can be aided by skin-prick testing. To avoid seasonal allergens, an athlete can limit outdoor training during certain times of the year or wear a filter mask. Tree pollens usually cause problems throughout the spring, and grasses produce allergens during the summer. Weed pollens tend to be elevated in the fall and perennially in warmer climates. Pollen levels drop after a rainfall, offering an opportunity for outdoor training. Avoiding perennial allergens is more difficult. In general, molds favor damp outdoor environments but may be abundant in older homes and buildings and in damp indoor areas. Indoor allergens can be minimized by cleaning damp areas with disinfectants or bleach, increasing ventilation, limiting carpeting and old upholstered furniture, eliminating indoor standing water, and avoiding excessive humidity and humidifiers. Controlling humidity can also help control dust mites, since they favor humid environments. The effects of dust mites can also be reduced by washing bedding regularly in hot water, having a nonallergic person vacuum and make beds, and covering all pillows and mattresses with an allergen barrier (1). Medication. The selection of medication should be based on the pathophysiology of the disease. If feasible, prophylactic treatment should be used to prevent the onset of significant symptoms. Once an allergic response is primed, treatment becomes more difficult. Five types of pharmacologic agents are commonly prescribed for the treatment of allergic rhinitis: antihistamines, decongestants, anticholinergics, cromolyn, and corticosteroids (table 1). A nasal corticosteroid is the most effective treatment for congestion and rhinorrhea, but significant improvement in symptoms may take a number of days and requires good compliance. Oral antihistamines, used as first-line therapy, do not work as well for congestion but reduce itching, sneezing, and rhinorrhea (3). "First generation" antihistamines, though less expensive than newer antihistamines, are less desirable in active persons because of their sedative effects.
Decongestants decrease congestion through intranasal vasoconstriction but do not have any effect on other allergy symptoms. Sympathomimetic side effects are common with oral preparations, and the use of topical preparations is limited to less than 5 days because of rebound congestion. Intranasal cromolyn is useful as an additional treatment in highly allergic individuals, particularly as a prophylaxis before a predicted allergen exposure or during the allergy season. Intranasal anticholinergic spray (eg, ipratropium bromide, 0.03%) is a useful second-line treatment for rhinorrhea that is not controlled with oral antihistamines or nasal corticosteroids. The use of several classes of pharmacologic agents, which act on different phases of the inflammatory response, may control symptoms more effectively than a single agent (4). Desensitization is often useful in a patient who requires multidrug treatment or in whom side effects are unacceptable, particularly if he or she has significant sensitivity to few allergens. Allergic ConjunctivitisAllergic conjunctivitis, which often accompanies allergic rhinitis but may also occur alone, includes acute, seasonal, and perennial conjunctivitis. Acute conjunctivitis occurs with direct exposure of the eye to an antigen, resulting in rapid and significant swelling of the conjunctiva. Seasonal and perennial forms of conjunctivitis are caused by the same allergens as seasonal and perennial rhinitis and therefore follow similar temporal patterns (5). Signs and symptoms of allergic conjunctivitis include watery, itchy eyes and mild conjunctival erythema and edema. The physical exam requires eversion of the eyelid to observe the extent of conjunctival involvement, since the palpebral and bulbar conjunctiva, normally concealed by the lids, may be the only areas significantly affected. Patients who have perennial symptoms generally have positive skin-prick tests, most often for dust mites, and eosinophils are often present in a conjunctival smear (6). The symptoms of allergic conjunctivitis can be alleviated by some of the same classes of agents used for symptomatic treatment of allergic rhinitis, including antihistamines and mast-cell stabilizers such as cromolyn sodium (4) and by topical nonsteroidal anti-inflammatory agents and topical vasoconstrictors (table 2) (7). Ophthalmic glucocorticoid solutions may provide dramatic relief of immune-mediated forms of conjunctivitis, but long-term use is not recommended. Patients who use opthalmic glucocorticoids run the risk of cataract formation and increased intraocular pressure that may lead to glaucoma. Further, the immunosuppressive actions of these agents set the stage for the onset or acceleration of secondary ocular infections. Thus, an ophthalmology consultation is recommended if a topical glucocorticoid is considered for treating allergic conjunctivitis.
AsthmaAsthma is characterized by reversible airway obstruction signaled by a reversible decrease in forced expiratory volume in one second (FEV1) of more than 15% in response to a trigger such as an allergen, respiratory irritant, or exercise. While the airway obstruction is intermittent, the underlying inflammatory process in patients who have persistent symptoms is ongoing and may result in airway remodeling. Allergies and exercise. Asthma is included in the discussion of allergic disease because allergies are a significant trigger in 50% of asthmatic adults (2). Furthermore, exercise-induced asthma (EIA), which affects 10% to 20% of all athletes, may affect up to 40% of athletes who have allergies (8). Food eaten before exercise may also aggravate bronchospasm for several days following exposure (9). Many athletes who have EIA complain of symptoms only with exercise, while 50% to 80% of patients who have persistent asthma have exercise-induced bronchospasm (8). In most cases, airway obstruction induced only by exercise represents a mild form of asthma, while airway obstruction triggered by multiple factors with more persistent symptoms indicates more severe disease. The risk of chronic inflammatory changes increases with the severity and persistence of symptoms. The prevalence of asthma is increasing in the general population and in athletes. In fact, it increased from 11% to 20% in Olympic athletes between the 1984 and 1996 Summer Olympics (10). With appropriate treatment, however, asthmatic Olympic athletes were as likely to win medals as nonasthmatic athletes. Winter Olympians may be even more susceptible to bronchospasm than their summer counterparts, possibly because of the exacerbating effects of cold, dry air. One study of cross-country skiers in Sweden demonstrated a 70% prevalence of EIA (11). Signs and symptoms. Typical signs and symptoms include a minimally productive or nonproductive cough, wheezing, shortness of breath, chest pain or tightness, inability to take a full breath, or difficulty in exhaling fully. Asthma is more likely in those who have a family or personal history of allergic disease. EIA symptoms tend to occur about 5 to 8 minutes after the onset of intense exercise (80% of VO2 max), are the most intense over the next 7 to 10 minutes, and begin to improve over the next 20 minutes (9). Despite similar levels of exertion, certain activities seem more asthmogenic than others. Outdoor running is the most asthmogenic, followed by indoor running, cycling, swimming, and walking. Cold, dry air is also more asthmogenic, and, not surprisingly, airborne pollutants aggravate bronchoconstriction in susceptible individuals. Clinicians must try to distinguish athletes who have persistent asthma from those who have EIA only, because the former require chronic anti-inflammatory treatment. Lung auscultation in a patient who has persistent asthma and active bronchoconstriction is generally abnormal, while the office exam of a person who has EIA only is usually normal. Typical pulmonary findings in acute asthma include wheezing, rhonchi, a prolonged expiratory phase, hyperinflation, and decreased breath sounds. The absence of wheezing during an acute attack should not be reassuring; it may be a sign that the airflow has diminished so much that it no longer generates sound. Signs of upper or lower respiratory tract infection or physical signs of other allergic disease should be noted. Diagnosic tests. If a patient has normal baseline spirometry, the diagnosis can be made by demonstrating a 15% drop in FEV1 following inhalation of a bronchial irritant, such as methacholine, or following an exercise challenge in those suspected of having EIA. Asthma is also diagnosed by demonstrating a 15% increase over baseline in FEV1 after administration of an inhaled beta-adrenergic agonist. Normal baseline FEV1 may not accurately identify or exclude asthma. Highly trained athletes may have a normal resting FEV1 or forced vital capacity and attain a 15% supranormal effect after using a bronchodilator. In a patient who has a history of asthma following exercise, a diagnosis of EIA can be made if the patient's postexercise symptoms fail to occur after he or she has been treated with an inhaled beta-adrenergic agonist before an exercise challenge. Airway obstruction can also be quantified by peak flow testing, but because this is more effort-dependent than spirometry, it is a less reliable diagnostic tool. However, peak flow can be very useful for monitoring the response to therapy in patients who have chronic symptoms. Athletes who have suspected allergic triggers and recalcitrant asthma should undergo skin-prick testing. The findings can help these athletes to avoid specific allergens and can suggest whether desensitization should be tried. Treatment. The goals of asthma treatment are to prevent chronic asthma symptoms and exacerbations; maintain normal daily activities, including exercise and other physical activities; maintain normal or near-normal lung function; and minimize or eliminate the side effects of medication (12). Nonpharmacologic. Nonpharmacologic treatment includes avoiding allergens, respiratory irritants, and other triggers as much as possible. Patients who have EIA should try to breathe through the nose rather than the mouth and should avoid exertion in excessively cold, dry, or polluted air. In addition, many athletes with EIA have a refractory period, in which symptoms decrease by 50% or more following an initial bout of exercise-induced bronchospasm. By provoking symptoms through exertion and then recovering before competition, 50% of athletes who have EIA are refractory for 60 minutes, and some may be refractory for up to 3 hours (13). Medications. Asthma medications can control symptoms in the short and long term. Long-term-control medications are taken daily to achieve and maintain control of persistent asthma (12,14). The most effective medications reduce inflammation, and the most potent anti-inflammatory medications are inhaled corticosteroids. Patients who have persistent asthma, whether mild, moderate, or severe, require daily anti-inflammatory medication for long-term control. Quick-relief medications, on the other hand, promptly alleviate acute airflow obstruction and its accompanying symptoms of cough, chest tightness, shortness of breath, and wheezing. These medications include short-acting inhaled beta-2 agonists and, in some cases, anticholinergics (table 3) (4). All asthma and EIA patients must have such a medication to take as needed.
A new group of medications—the leukotriene antagonists—inhibit the bronchospastic and inflammatory effects of leukotrienes, which play a significant role in asthma induced by exercise, aspirin, or allergens (14-16). Though the specific indications for these drugs are still being established, patients who have aspirin- or exercise-induced asthma have benefited from their use (15). These medications are currently recommended as an add-on therapy for all asthmatics. For the use of these medications in patients who have EIA, see "Controlling Exercise-Induced Asthma," below. Atopic DermatitisAtopic dermatitis may be an IgE-mediated chronic inflammatory skin condition. It often occurs with other allergic syndromes and is frequently the first manifestation of allergic disease in children. Triggers include a variety of food and airborne allergens, skin infection, skin irritants, emotional stress, and environmental factors, including cold, dry air. Food sensitivity is common in children, while adults are generally more sensitive to airborne allergens or other irritants. In athletes, allergic dermatitis can be exacerbated by skin irritation from protective equipment, excessive sweating, or physical trauma. Outdoor winter sports enthusiasts are particularly susceptible because of skin dehydration from cold, dry air. Diagnosis. Patients generally complain of pruritus and a rash involving the antecubital and popliteal fossae as well as the face, hands, and feet. Physical examination may demonstrate acute pruritic lesions, with skin erythema, papules, and vesicles. Subacute lesions progress to scaling, with early evidence of excoriation, while chronic lesions appear as thickened plaques, lichenification, and prurigo nodularis (17). Patients are susceptible to bacterial and viral superinfection, which can result in acute erythema, tenderness, discharge, crusting, or vesiculation overlying chronic changes. A family and/or personal history of atopy is common. Patients often have elevated serum IgE, but the diagnosis is made clinically, and determining the serum level is not usually necessary or cost-effective. Positive skin-prick testing can document atopy. Identifying the offending agent, though, requires controlled elimination of suspected allergens, since the skin disease usually is the result of sensitivity to only a few of the allergens for which the patient tests positive. Correct identification of problematic foods is particularly important for athletes, since they should avoid an overly restricted diet (17). Treatment. Treatment involves a combination of preventive measures and an individualized therapeutic regimen. Patients should generally avoid the excessive use of soap while bathing and afterwards should use emollients, ideally petrolatum. They should also avoid irritants such as detergents, solvents, wool, and lanolin. Topical steroids of the lowest effective potency are the mainstay of therapy for atopic dermatitis (table 4) and may be used in conjunction with topical antibiotics such as mupirocin ointment and emollients (18,19). Topical coal tar may help some patients, though its messiness often results in poor compliance.
Oral antibiotics are used to treat secondary staphylococcal colonization or infection, and oral antihistamines may decrease pruritus. Systemic corticosteroids are extremely effective for severe, acute flairs of atopic dermatitis, but adverse effects limit prolonged use. Phototherapy that combines ultraviolet A and B rays of various frequencies may be used to treat atopic dermatitis that does not respond to topical therapy (19). Restricted MedicationsBecause some medications are banned by sports governing bodies, certain therapies may not be available for competitive athletes. Current listings of the National Collegiate Athletic Association's (NCAA's) banned substances can be found on the World Wide Web at http://www.ncaa.org/sports_sciences/drugtesting, and inquiries regarding the International Olympic Committee's (IOC) banned substances can be made by calling the Olympic Drug Reference Line (1-800-233-0393). None of the previously discussed treatments is included on the 1998-99 NCAA Banned-Drug Classes. However, several are either restricted or prohibited under current IOC regulations:
Management for PerformanceAllergen-mediated diseases affect millions of active persons and athletes. Fortunately, current treatments can relieve most symptoms sufficiently to permit active patients to continue exercising and athletes to compete at the highest levels. Physicians who care for these individuals must maintain a high index of suspicion for these conditions and manage them aggressively to maximize patients' quality of life and athletic performance. References
Controlling Exercise-Induced AsthmaPatients who have exercise-induced asthma (EIA) alone or who have chronic asthma that is exacerbated by exercise have the best chance of controlling symptoms during exercise through careful timing of and/or combining medications. For control of EIA, patients usually begin by using a short-acting beta-agonist, taking two to four puffs 5 to 60 minutes before exercise. The effects should last 2 to 3 hours. A long-acting medication is an alternative if prolonged exertion is anticipated and repeated dosing of a short-acting medication is impractical. The effects of a long-acting beta-2 agonist taken at least 30 minutes before exercise will last 10 to 12 hours; however, recent evidence suggests that these protective effects decrease when the medications are used regularly for as little as 14 days (1,2). Cromolyn or nedocromil may also be used before exertion; the effect lasts 1 to 2 hours. The combination of cromolyn and albuterol has been shown to be more potent than either alone (1). If exercise-induced symptoms persist in a patient who has lone EIA despite these treatments, regular treatment with inhaled corticosteroids and/or leukotriene antagonists often provides benefits (3). Athletes who require regular anti-inflammatory therapy to control EIA may, in fact, have chronic asthma and should be evaluated further. Chronic asthmatics who already receive regular anti-inflammatory medication may benefit from increased dosages or a combination of a leukotriene antagonist and an inhaled corticosteroid. Concomitant allergic rhinitis or sinusitis should always be addressed to optimize symptom control. References
Dr O'Kane is an assistant professor of orthopedics and family medicine and a team physician at the University of Washington in Seattle; he is a member of the American Medical Society for Sports Medicine. Dr Woodford is a pharmacy resident in family medicine at the University of Washington. Address correspondence to John W. O'Kane, MD, Dept of Orthopaedics, University of Washington, Box 354060, Seattle, WA 98195-4060; address e-mail to jokane@u.washington.edu.
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