CHAPTER 79 Allergic Rhinitis
ETIOLOGY
Rhinitis describes diseases that involve inflammation of the nasal epithelium and is characterized by sneezing, itching, rhinorrhea, and congestion. There are many different causes of rhinitis in children, but approximately half of all cases of rhinitis are caused by allergies.
Allergic rhinitis, commonly known as hay fever, is caused by a type I, IgE-mediated allergic response. During the early allergic phase, mast cells degranulate and release preformed chemical mediators, such as histamine and tryptase, and newly generated mediators, such as leukotrienes, prostaglandins, and platelet-activating factor. After a quiescent phase in which other cells are recruited, a late phase occurs approximately 4 to 8 hours later. Eosinophils, basophils, CD4 T cells, monocytes, and neutrophils release their chemical mediators, which leads to the development of chronic nasal inflammation.
Allergic rhinitis can be seasonal, perennial, or episodic depending on the particular allergen and the exposure. Some children experience perennial symptoms with seasonal exacerbations. Seasonal allergic rhinitis is caused by airborne pollens, which have seasonal patterns. Insect-pollinated plants (flowers, flowering trees) are not a cause of allergic rhinitis. Typically, trees pollinate in the spring, grasses in late spring to summer, and weeds in the summer and fall. The pollen, microscopic in size, can travel airborne hundreds of miles and be inhaled easily into the respiratory tract. Perennial allergic rhinitis is primarily caused by indoor allergens, such as house dust mites, animal dander, mold, and cockroaches. Episodic rhinitis occurs with intermittent exposure to allergens, such as visiting a friend’s home where a pet dwells.
Genetic predisposition and repeated exposure to allergens contribute to the development of allergic rhinitis. It often takes weeks, months, or years to sensitize the immune system to produce sufficient allergen-specific IgE. When an atopic child inhales airborne allergens, these proteins penetrate the nasal mucosal epithelium and interact with allergen-specific IgE on tissue mast cells. Allergic rhinitis is relatively rare in children younger than 6 months of age. If present in infancy, it is caused by foods or household inhalants rather than seasonal pollens. Typically, seasonal allergic rhinitis presents in children older than 3 years of age.
EPIDEMIOLOGY
Chronic rhinitis is one of the most common disorders encountered in infants and children. Overall, allergic rhinitis is observed in 10% to 25% of the population, with children and adolescents more commonly affected than adults. The prevalence of physician-diagnosed allergic rhinitis may be 40%.
CLINICAL MANIFESTATIONS
The hallmarks of allergic rhinitis are clear, thin rhinorrhea; nasal congestion; paroxysms of sneezing; and pruritus of the eyes, nose, ears, and palate. Postnasal drip may result in frequent attempts to clear the throat, nocturnal cough, and hoarseness. It is important to correlate the onset, duration, and severity of symptoms with seasonal or perennial exposures, changes in the home or school environment, and exposure to nonspecific irritants, such as tobacco smoke.
The physical examination includes a thorough nasal examination and an evaluation of the eyes, ears, throat, chest, and skin. Physical findings may be subtle. Classic physical findings include pale pink or bluish gray, swollen, boggy nasal turbinates with clear, watery secretions. Frequent nasal itching and rubbing of the nose with the palm of the hand, the allergic salute, can lead to a transverse nasal crease found across the lower bridge of the nose. Children may produce clucking sounds by rubbing the soft palate with their tongue. Oropharyngeal examination may reveal lymphoid hyperplasia of the soft palate and posterior pharynx or visible mucus or both. Orthodontic abnormalities may be seen in children with chronic mouth breathing. Allergic shiners, dark periorbital swollen areas caused by venous congestion, are often present in children along with swollen eyelids or conjunctival injection. Retracted tympanic membranes from eustachian tube dysfunction or serous otitis media also may be present. Other atopic diseases, such as asthma or eczema, may be present, which helps lead the clinician to the correct diagnosis.
LABORATORY AND IMAGING STUDIES
Allergy testing can be performed by in vivo skin tests or by in vitro serum tests (radioallergosorbent test [RAST]) to pertinent allergens found in the patient’s environment (see Table 77-4). Skin tests (prick/puncture) provide immediate and accurate results. Positive tests correlate strongly with nasal and bronchial allergen provocative challenges. In vitro serum tests are useful for patients with abnormal skin conditions, a tendency for anaphylaxis, or those taking medications that interfere with skin testing. Disadvantages of serum tests include increased cost, inability to obtain immediate results, and reduced sensitivity compared with skin tests. Widespread screening with serum testing without regard to symptoms is not recommended. Measurement of total serum IgE or blood eosinophils generally is not helpful. The presence of eosinophils on the nasal smear suggests a diagnosis of allergy, but eosinophils also can be found in patients with nonallergic rhinitis with eosinophilia. Nasal smear eosinophilia is often predictive of a good clinical response to nasal corticosteroid sprays.
DIFFERENTIAL DIAGNOSIS
Rhinitis can be divided into allergic and nonallergic rhinitis (Table 79-1). Nonallergic rhinitis describes a group of nasal diseases in which there is no evidence of allergic etiology. It can be divided further into nonanatomic and anatomic etiologies. The most common form of nonallergic rhinitis in children is infectious rhinitis, which may be acute or chronic. Acute infectious rhinitis (the common cold) is caused by viruses, including rhinoviruses and coronaviruses, and typically resolves within 7 to 10 days (see Chapter 102). An average child has three to six common colds per year, with younger children and children attending day care the most affected. Infection is suggested by the presence of sore throat, fever, and poor appetite, especially with a history of exposure to others with colds. Chronic infectious rhinosinusitis, or sinusitis, should be suspected if there is mucopurulent nasal discharge with symptoms that persist beyond 10 days (see Chapter 104). Classic signs of acute sinusitis in older children include facial tenderness, tooth pain, headache, and fever. Classic signs are usually not present in young children who may present with postnasal drainage with cough, throat clearing, halitosis, and rhinorrhea. The character of the nasal secretions with infectious rhinitis varies from purulent to minimal or absent. Coexistence of middle ear disease, such as otitis media or eustachian tube dysfunction, may be additional clues of infection.
TABLE 79-1 Classification of the Etiology of Rhinitis in Children
| Allergic | Nonallergic | |
|---|---|---|
| Nonanatomic | Anatomic | |
| Seasonal | Nonallergic, noninfectious (vasomotor) rhinitis | Adenoidal hypertrophy |
| Perennial | Infectious rhinosinusitis | CSF rhinorrhea |
| Episodic | Nonallergic rhinitis with eosinophilia | Choanal atresia |
| Physical rhinitis | Congenital anomalies | |
| Rhinitis medicamentosa | Foreign body | |
| Nasal polyps | ||
| Septal deviation | ||
| Tumors | ||
| Turbinate hypertrophy | ||
CSF, cerebrospinal fluid.
Nonallergic, noninfectious rhinitis (formerly known as vasomotor rhinitis) can manifest as rhinorrhea and sneezing in children with profuse clear nasal discharge. Exposure to irritants, such as cigarette smoke and dust, and strong fumes and odors, such as perfumes and chlorine in swimming pools, can trigger these nasal symptoms. Nonallergic rhinitis with eosinophilia syndrome is associated with clear nasal discharge and eosinophils on nasal smear and is seen infrequently in children. Cold air (skier’s nose), hot/spicy food ingestion (gustatory rhinitis), and exposure to bright light (reflex rhinitis) are examples of physical rhinitis. Treatment with topical ipratropium before exposure may be helpful.
Rhinitis medicamentosa, which is due primarily to overuse of topical nasal decongestants such as oxymetazoline, phenylephrine, or cocaine, is not a common condition in younger children. Adolescents or young adults may become dependent on these over-the-counter medications. Treatment requires discontinuation of the offending decongestant spray, topical corticosteroids, and, frequently, a short course of oral corticosteroids.
The most common anatomic problem seen in young children is obstruction secondary to adenoidal hypertrophy, which can be suspected from symptoms such as mouth breathing, snoring, hyponasal speech, and persistent rhinitis with or without chronic otitis media. Infection of the nasopharynx may be secondary to infected hypertrophied adenoid tissue.
Choanal atresia is the most common congenital anomaly of the nose and consists of a bony or membranous septum between the nose and pharynx, either unilateral or bilateral. Bilateral choanal atresia classically presents in neonates as cyclic cyanosis because neonates are preferential nose breathers. Airway obstruction and cyanosis are relieved when the mouth is opened to cry and recurs when the calming infant reattempts to breathe through the nose. Some newborns show respiratory difficulty only while feeding. Nearly half of infants with choanal atresia have other congenital anomalies as a part of the CHARGE association (coloboma, congenital heart disease, choanal atresia, retardation, genitourinary defects, ear anomalies). Unilateral choanal atresia may go undiagnosed until later in life and presents with symptoms of unilateral nasal obstruction and discharge.
Nasal polyps typically appear as bilateral, gray, glistening sacs originating from the ethmoid sinuses and may be associated with clear or purulent nasal discharge. Nasal polyps are rare in children younger than 10 years of age but if present warrant evaluation for an underlying disease process, such as cystic fibrosis or primary ciliary dyskinesia. Triad asthma is asthma, aspirin sensitivity, and nasal polyps with chronic or recurrent sinusitis.
Foreign bodies are seen more commonly in young children who hide food, small toys, stones, or erasers in their nose. The index of suspicion should be raised by a history of unilateral, purulent nasal discharge, or foul odor. The foreign body can often be seen on examination with a nasal speculum.
Nasal septal deviation in infants can be congenital or the result of birth trauma. In older children, facial trauma from contact sports, automobile or bicycle accidents, or play activities can result in septal deformity. Hypertrophy of the turbinates causing nasal symptoms also can be seen in children. Severe anatomic abnormalities of the septum or turbinates may benefit from surgical intervention.
A rare cause of rhinitis is cerebrospinal fluid rhinorrhea. This condition should be suspected in the presence of unilateral, clear nasal discharge and may occur even in the absence of trauma or recent surgery.
Tumors are extremely rare causes of anatomic obstruction in children and include hemangioma, rhabdomyosarcoma, lymphoma, and olfactory neuroblastoma. Other unusual congenital nasal lesions include dermoid cysts, teratomas, gliomas, and encephaloceles that present as insidious nasal obstruction in children. In adolescent boys, nasal obstruction and severe, recurring nosebleeds may be a sign of angiofibroma, a benign tumor.
TREATMENT
Management of allergic rhinitis is based on disease severity, impact of the disease on the patient, and the ability of the patient to comply with recommendations. Treatment modalities include allergen avoidance, pharmacologic therapy, and immunotherapy. Environmental control and steps to minimize allergen exposure, similar to preventive steps for asthma, should be implemented whenever possible (see Table 78-3).
Pharmacotherapy
Intranasal corticosteroids are the most potent pharmacologic therapy for treatment of allergic and nonallergic rhinitis. These include beclomethasone, budesonide, ciclesonide, flunisolide, fluticasone, mometasone, and triamcinolone. These topical agents work to reduce inflammation, edema, and mucus production. They are effective for symptoms of nasal congestion, rhinorrhea, itching, and sneezing but less helpful for ocular symptoms. Nasal corticosteroid sprays have been used safely in long-term therapy. Deleterious effects on adrenal function or nasal membranes have not been reported when these agents are used appropriately. The most common adverse effects include local irritation, burning, and, sneezing, which occur in 10% of patients. Nasal bleeding from improper technique (spraying the nasal septum) can occur. Rare cases of nasal septal perforation have been reported.
Antihistamines are the medications used most frequently to treat allergic rhinitis. They are useful in treating rhinorrhea, sneezing, nasal itching, and ocular itching but are less helpful in treating nasal congestion. First-generation antihistamines, such as diphenhydramine and hydroxyzine, easily cross the blood-brain barrier, with sedation as the most common reported adverse effect. Use of first-generation antihistamines in children has an adverse effect on cognitive and academic function. In very young children, a paradoxical stimulatory central nervous system effect, resulting in irritability and restlessness, has been noted. Other adverse effects of first-generation antihistamines include anticholinergic effects, such as blurred vision, urinary retention, dry mouth, tachycardia, and constipation. Second-generation antihistamines, such as cetirizine, loratadine, desloratadine, fexofenadine and levocetirizine, are less likely to cross the blood-brain barrier, resulting in less sedation. Cetirizine and loratadine are now over-the-counter medications. Azelastine and olopatadine, topical nasal antihistamine sprays, are approved for children older than 5 years and older than 6 years, respectively.
Decongestants, taken orally or intranasally, may be used to relieve nasal congestion. Oral medications, such as pseudoephedrine and phenylephrine, are available either alone or in combination with antihistamines. Adverse effects of oral decongestants include insomnia, nervousness, irritability, tachycardia, tremors, and palpitations. For older children participating in sports, oral decongestant use may be restricted. Topical nasal decongestant sprays are effective for immediate relief of nasal obstruction but should be used for less than 5 to 7 days to prevent rebound nasal congestion (rhinitis medicamentosa).
Topical ipratropium bromide, an anticholinergic nasal spray, is used primarily for nonallergic rhinitis and rhinitis associated with viral upper respiratory infection. Leukotriene modifiers have been studied in the treatment of allergic rhinitis. Montelukast is approved for use in seasonal allergic rhinitis.
Immunotherapy
If environmental control measures and medication intervention are only partially effective or produce unacceptable adverse effects, immunotherapy may be recommended. The mechanism of action for allergen immunotherapy is complex but includes increased production of an IgG-blocking antibody, decreased production of specific IgE, and alteration of cytokine expression produced in response to an allergen challenge. Immunotherapy is effective for desensitization to pollens, dust mites, and cat and dog proteins. Use in young children may be limited by the need for frequent injections. Immunotherapy must be administered in a physician’s office with 20 to 30 minutes of observation after the allergen injection. Anaphylaxis may occur, and the physician must be experienced in the treatment of these severe adverse allergic reactions.
COMPLICATIONS
Approximately 60% of children with allergic rhinitis have symptoms of reactive airways disease/asthma (see Chapter 78). Chronic allergic inflammation leads to chronic cough from postnasal drip; eustachian tube dysfunction and otitis media; sinusitis; and tonsillar and adenoid hypertrophy, which may lead to obstructive sleep apnea. Children with allergic rhinitis may experience sleep disturbances, limitations of activity, irritability, and mood and cognitive disorders that adversely affect their performance at school and their sense of well-being.
PROGNOSIS AND PREVENTION
Seasonal allergic rhinitis is a common and prominent condition that may not improve as children grow older. Patients become more adept at self-management. Perennial allergic rhinitis improves with allergen control of indoor allergens.
Removal or avoidance of the offending allergen is advised. The only effective measure for minimizing animal allergens from pets is removal of the pet from the home. Avoidance of pollen and outdoor molds can be accomplished by staying indoors in a controlled environment. Air conditioning and keeping windows and doors closed lower exposure to pollen. High-efficiency particle air (HEPA) filters reduce exposure to allergens (e.g., pet dander, mold spores, or pollen granules). Sealing the mattress, pillow, and covers in allergen-proof encasings is the most effective strategy for reduction of mite allergen. Bed linens and blankets should be washed in hot water (>130 °F) every week.