eMedicine Specialties > Pediatrics: General Medicine > Allergy & Immunology

Allergic Rhinitis

Author: Jack M Becker, MD, Chief of Asthma, Allergy and Immunology, Department of Pediatrics, St Christopher's Hospital for Children
Contributor Information and Disclosures

Updated: Sep 26, 2007

Introduction

Background

Although allergic rhinitis (AR) is a common disease, the impact on daily life cannot be underestimated. Some patients find AR to be just as debilitating and intrusive as severe asthma. Employees with untreated allergies are reportedly 10% less productive than coworkers without allergies, whereas those using allergy medications to treat AR were only 3% less productive.¹ This suggests that effective medications may reduce the overall cost of decreased productivity. AR is caused by an immunoglobulin E (IgE)–mediated reaction to various allergens in the nasal mucosa. The most common allergens include dust mites, pet danders, cockroaches, molds, and pollens.

The allergen present in the outdoor environment varies with the time of year and location. Knowing what allergens are in the environment at a specific time of year helps in diagnosing and treating AR and helps in excluding allergy as a cause of the patient's symptoms. For example, a patient who presents with nasal congestion in November in Boston, Mass cannot have AR attributed to tree pollen allergy, which is prevalent in spring. Allergens bound to allergen-specific IgE antibodies that are bound to mast cells cause a release of a wide range of mediators, which leads to AR symptoms, including sneezing; nasal congestion; stuffiness; rhinorrhea; cough; itching of the nose, eyes, and throat; sinus pressure; headache; and epistaxis.

Allergen exposure likely causes both upper and lower airway inflammation. Many experts believe that a patient's airway needs to be evaluated as a total entity, not as individual parts. Studies have shown that most patients with asthma also have AR. Allergic reactions of the upper airway can trigger lower airway symptoms and vice versa. One study showed that patients with untreated AR and asthma have an almost 2-fold greater risk of having an emergency room visit and almost a 3-fold greater risk of being hospitalized for an asthma exacerbation, respectively.²

See Media files 3-5 for graphs that detail the significant impact of nasal allergies.

Pathophysiology

Understanding the function of the nose is important in order to understand AR. The purpose of the nose is to filter, humidify, and regulate the temperature of inspired air. This is accomplished on a large surface area spread over 3 turbinates in each nostril. A triad of physical elements (ie, a thin layer of mucus, cilia, and vibrissae [hairs] that trap particles in the air) accomplishes temperature regulation. The amount of blood flow to each nostril regulates the size of the turbinates and affects airflow resistance. The nature of the filtered particles can affect the nose. Irritants (eg, cigarette smoke, cold air) cause short-term rhinitis; however, allergens cause a cascade of events that can lead to more significant inflammatory reactions.

In short, rhinitis results from a local defense mechanism in the nasal airways that attempts to prevent irritants and allergens from entering the lungs.

Allergic reactions require exposure and then sensitization to allergens. To be sensitized, the atopic patient must be exposed to allergens for a period of time. Sensitization to highly allergenic indoor allergens can occur in children younger than 2 years. Sensitization to outdoor allergens usually occurs when a child is older than 3-5 years, and the average age at presentation is 9-10 years. The allergic reaction begins with the cross-linking of the allergen to 2 adjacent IgE molecules that are bound to high-affinity Fcε receptors on the surface of a mast cell. This cross-linking causes mast cells to degranulate, releasing various mediators. The best-known mediators are histamine, prostaglandin D₂, tryptase, heparin, and platelet-activating factor, as well as leukotrienes and other cytokines.

These substances produce 2 types of reactions: immediate and late-phase. The immediate reactions in the nasal mucosa induce acute allergy symptoms (eg, nasal itch, clear nasal discharge, sneezing, congestion). The late-phase reaction occurs hours later, secondary to the recruitment of inflammatory cells into the tissue by the action of mediators released by the mast cell. Recruited cells are predominated by eosinophils and basophils, which, in turn, release their inflammatory mediators, leading to continuation of the cascade. In very sensitive individuals, this allergen-induced nasal inflammation causes priming of the nasal mucosa. Primed nasal mucosa becomes hyperresponsive, at which point even nonspecific triggers or small amounts of the antigen can cause significant symptoms.

Frequency

United States

Prevalence in the United States is 10-20%.³ One survey demonstrated rates as high as 38.2% when patients were asked if they experienced fewer than 7 days of symptoms. When AR was defined as symptoms lasting more than 31 days, prevalence dropped to 17%.

International

In temperate areas of Europe and Asia, frequency is similar to that in the United States.

Mortality/Morbidity

Mortality is not associated with AR, but significant morbidity occurs. Morbidity is manifested in several ways.

• Annually, an estimated 824,000 school days are missed, and an estimated 4,230,000 days of reduced quality-of-life functions are reported.⁴
• Comorbidity of other atopic diseases (asthma, atopic dermatitis) or upper airway inflammation (sinusitis, otitis media) is significant in AR. Individuals with AR have a higher frequency of these conditions than individuals without AR.
• Quality-of-life surveys revealed that patients with significant AR found symptoms to be just as debilitating as symptoms in patients with moderate-to-severe asthma. Patients with AR felt they were equally impaired and unable to participate in the activities of normal living similar to those with the moderate-to-severe asthma. They felt that chronic congestion, sneezing, the need to wipe the nose, and a decrease in restful sleep compromised levels of their daily activity.
• The financial cost of AR is difficult to estimate. Self-treating patients are estimated to spend an average of 56 dollars per year. The direct cost of prescription medication exceeds 6 billion dollars per year worldwide, and lost productivity is estimated at 1.5 billion dollars per year.

Race

AR has no race predilection; however, individuals from non-Caucasian backgrounds seek out medical attention less often than Caucasians.

Sex

AR has no sex predilection.

Age

AR usually presents in early childhood. AR caused by sensitization to outdoor allergens can occur in children older than 2 years; however, sensitization in children aged 4-6 years is more common. Clinically significant sensitization to indoor allergens may occur in children younger than 2 years. This is typically associated with significant exposures to indoor allergens (eg, molds, furry animals, cockroaches, dust mites). Some children may be sensitized to outdoor allergens at this young age if they have significant exposure. Incidence continues to increase until the fourth decade of life, when symptoms begin to fade; however, individuals can develop symptoms at any age.

Clinical

History

The history of the patient with nasal symptoms may be straightforward or may include a complex set of symptoms. The diagnosis is easy to make in a patient with a new pet or with symptoms that have distinct seasonal variation. Alternatively, younger patients may present with varying signs or symptoms, the family may not appreciate the nasal stuffiness but may note the chronic congestion. In older children, symptoms may have been present for years and, therefore, appear to be less severe because the child has accommodated them.

Physicians should try to identify seasonal variations, provocative elements in the environment, and the timing of events that lead to symptoms. Few patients present soon after the onset of allergic rhinitis (AR) symptoms. Usually, AR symptoms have been present for years and have been slowly worsening during each allergy season. In fact, a patient who describes a sudden onset of nasal allergy symptoms, unless a new exposure to large amounts of allergens is reported (eg, pet, feather pillow), is not experiencing allergic symptoms. Sudden onset of nasal symptoms is often associated with acute sinusitis or acute bacterial sinusitis superimposed on chronic sinusitis. In children younger than 5 years, differentiating allergy symptoms from recurrent upper respiratory viral infection is even more difficult, especially in children who attend daycare and experience frequent rhinitis symptoms.

• Nature of symptoms
  • Symptoms of rhinitis consist of rhinorrhea, nasal congestion, postnasal drainage, repetitive sneezing, and itching of the palate, nose, or eyes. Snoring, frequent sore throats, constant clearing of the throat, cough, itchy eyes, and headaches are symptoms often associated with rhinitis.
  • When obtaining the history, ascertain the following:
    • Determine which symptoms are reported by the patient or parent.
    • Determine whether the patient has rhinorrhea, sniffling, nasal itching, sneezing, cough, congestion, or nasal discharge. Determine the color of the nasal discharge.
    • Determine whether any associated ocular or respiratory symptoms are present.
• Timing of symptoms
  • Identify whether symptoms are present or worsen during certain seasons, such as the spring or fall. In addition, try to identify whether symptoms are worse in specific places, such as home, work, or school, or when the patient is around animals.
  • Determine when symptoms occur and whether they occur primarily at night, in school, outdoors, or at a relative's or friend's home.
  • Determine whether symptoms occur only at a certain time of the year or throughout the year.
  • Determine whether symptoms ever improve and, if so, what actions help alleviate symptoms. Most patients have tried over-the-counter antihistamine medication. If these medications help, AR should be suspected; however, a negative response does not eliminate the possibility of AR.
  • Determine whether symptoms improve when the patient is taking antibiotics. Most patients receive antibiotics for various reasons unrelated to nasal symptoms. If symptoms respond to antibiotic therapy, the clinical diagnosis may be sinusitis, which may have been either primary sinusitis or secondary sinusitis caused by AR.
• Duration of symptoms
  • Determine whether symptoms last for weeks, months, or hours.
  • Most pollen seasons are at least 6 weeks long in more moderate climates. In the south and far north, the season can be longer or shorter, respectively. Symptoms that last less than 2 weeks rarely indicate AR unless concomitant exposure occurs.
  • In winter in the northern regions, virtually all pollens are absent; therefore, any AR-like symptoms are the result of indoor allergen exposure or are not caused by allergen exposure. Although patients are usually exposed to the same allergens throughout the year, AR symptoms triggered by indoor allergens can worsen in winter secondary to longer hours spent indoors during the cold months. This may also be associated with closed windows and doors in winter, resulting in increased recirculation of indoor allergens. An example of winter-only exposure is a person who is allergic to dust mites who uses a down comforter only during the winter (dust mites are highly infested in a down comforter.)
• Family history
  • Children with parents who have allergies or asthma are more likely to be affected.
  • If a child has one parent with allergies, chances are 30% that a child will have AR. This increases to 50-70% if both parents have allergies or asthma.
• Related medical history
  • Patients with a history of infantile eczema (atopic dermatitis) have a 70% chance of having AR, asthma, or both.
  • Patients with a history of asthma also have higher incidence of AR.
• Social and environmental history
  • The patient's environment is very important. Ask about the presence of a pet or feathers (eg, pillow, bedspread, comforter) in the home and the timing of initial exposure. Many times, exposure to feathers or pets coincides with the onset of symptoms, making diagnosis and treatment easier. However, patients could become sensitized to indoor allergens by exposure in places other than the home where they spend a fair numbers of hours (eg, schools, daycare center).
  • Questions must be raised regarding any environment in which the patient spends more than a few hours per week. This includes baby-sitters' and relatives' homes, daycare facilities, and schools (classroom pets).
  • For children younger than 3 years, ask about the child's bed. Cribs or toddler beds that use crib mattresses do not have dust mites because of the plastic covers, but standard bedding (bed mattress) can harbor dust mites.

Physical

A full examination should always be performed to detect other diseases, such as asthma, eczema, and cystic fibrosis, which occur in connection with AR. Evaluation involves the head, eyes, ears, nose, and throat. Upon inspection, the following signs can be noted:

• Head
  • Allergic shiners (dark, puffy, lower eyelids) may be present.
  • Morgan-Dennie lines (lines under the lower eyelid) may be observed.
  • Transverse crease at the lower third of the nose secondary to the allergic salute, which is the upward rubbing of the nose, is commonly seen in parents as well.
• Eyes
  • Marked erythema of palpebral conjunctivae and papillary hypertrophy of tarsal conjunctivae are observed. Chemosis of the conjunctivae may be present. Patients usually have a watery discharge.
  • Cataracts have occurred from severe rubbing secondary to itching.
• Ears
  • Tympanic membranes should be examined for the presence of chronic infection or middle ear effusion.
  • The role of AR in chronic otitis media is not clear, but decreased numbers of infections have been noted in children with AR once therapy was instituted.
• Nose
  • Nasal examination is often helpful in the diagnosis.
  • Turbinates are enlarged and have a pale-bluish mucosa due to edema.
  • Discharge is usually clear but can be white. The discharge is rarely yellow or green. If colored discharge is observed, a diagnosis of viral infection or sinusitis should be considered.
  • Dried blood is commonly observed secondary to trauma from rubbing the nose.
  • Polyps are rarely observed in children. If polyps are noted or suspected, perform rhinoscopy. If polyps are detected, a workup for cystic fibrosis is mandatory in children. Also consider the diagnosis of aspirin sensitivity in adults.
• Throat
  • Inspection of the dentition can be informative. Discoloration of frontal incisors and a high arched palate are associated with chronic mouth breathing. Malocclusion is commonly associated with chronic mouth breathing.
  • Cobblestoning in the posterior pharynx is also a sign of follicular hypertrophy of mucosal lymphoid tissue secondary to chronic nasal congestion and postnasal drainage.
  • Note the size of tonsillar tissue, which may provide a clue to the size of the adenoids; large adenoids can mimic the signs and symptoms of AR. Chronic nasal congestion due to adenoid hypertrophy is frequently seen in young children with recurrent otitis media and sinusitis.

Causes

• Perennial symptoms are usually caused by indoor allergens, including the following:
  • Dust mites
  • Cat dander
  • Dog dander
  • Indoor molds
  • Cockroaches
  • Feathers (In most occasions, feather pillows and comforters are highly allergenic, secondary to dust mite infestation.)
  • Other furry animals
• Seasonal symptoms are usually caused by airborne pollen and outdoor molds, including the following:
  • Tree pollen
  • Grass pollen
  • Outdoor mold spores
  • Weed pollen (Flowers do not cause AR because they do not use wind-borne pollination.)

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